Where Does Green Hydrogen Fit?

Image credit: Google Gemini

If you know my writing even a little, you’ll know where I stand on this issue.  It’s as simple as my meme, but my many articles (especially this one) explain why, in detail.  Those articles come with analysis and references and the comments of many experts in the field as an informal peer review too.

https://www.linkedin.com/pulse/distilled-thoughts-hydrogen-paul-martin

So…where does green hydrogen fit?  The simple answer is that it fits a) where it can be made truly green b) for applications where we need the special properties of hydrogen as a molecule, for things which are durable in a decarbonized future.

Where can we make hydrogen that is truly green? Since it is an economic myth that we can make affordable hydrogen only from electricity that would otherwise be curtailed, and because the obvious highest value use for green electricity is to replace BLACK electricity (electricity made from fossils without carbon capture), it stands to reason that we can only make green hydrogen where and when the local grid is already as green as we can manage to make it in practical terms. Sadly, at present, that means only in places where the potential to make new green electricity greatly exceeds the ability of people within reach of an HVDC cable (i.e. within a few thousand kilometres by land or sea) to make use of that electricity. Everywhere else, that electricity’s highest value use for decarbonization isn’t to make hydrogen- it’s to use it to displace dirty electricity from the grid.

If we do make some green hydrogen that we think we can afford, it similarly isn’t really “green” unless we use that hydrogen for uses that require hydrogen, and which will survive in a decarbonized economy. Those applications are largely things we use dirty, fossil-derived, high CO2e emission hydrogen for today.  And that’s substantially all the hydrogen in the world today- 99%+ of it is made to the tune of over 120 million tonnes/yr, not to waste as a fuel, but we make it from fuels, with CO2 and methane and toxic combustion emissions going to the atmosphere as a result.  And by my estimation, the making of this fossil-derived hydrogen- and there’s nothing “gray” about it, it’s blacker than black in terms of emissions- has CO2 emissions greater than those of aviation and almost greater than those of both aviation and shipping combined.

Existing Uses of Hydrogen

The three major categories of hydrogen demand are ammonia, petroleum refining, and everything else.  Each of these consumes about 1/3 of world hydrogen production.  The figures for hydrogen production and consumption by sector, both pure and in syngas (mixtures with carbon monoxide or CO) are from the IEA via IRENA and are referenced here:

IRENA IEA H2 use vs time 2018

Ammonia

Ammonia is the toxic gas that is keeping half the humans and their food animals on earth, alive by feeding them.  A deeply ironic state of affairs, with huge emissions that we must reduce.

https://www.linkedin.com/pulse/ammonia-pneumonia-paul-martin

 We use about 40 million tonnes/yr of hydrogen, substantially all of it blacker than black, to make ammonia, which is the source of all our nitrogen fertilizers and also the base of the entire nitrogen chemicals industry on earth.  We make so much ammonia that we humans are fully half the nitrogen cycle on earth.  (Note that while we are, with scientific certainty, wrecking the stability of the climate by burning fossils and emitting fossil CO2 to the atmosphere, it is the cumulative effect of doing that over decades which is the problem- despite the fact that we humans and all our activities represent a small fraction of the annual carbon cycle on earth.) 

The emissions from ammonia production are not just from the CO2e-emissive process of making the hydrogen that we then react with nitrogen to make ammonia itself, but also from the N2O emissions (a very powerful and persistent GHG) which inevitably result when we apply ammonia, and nitrates and urea made from ammonia, to agricultural soils.  We need to improve agricultural practices to reduce those N2O emissions.  But we also can and must reduce how much CO2e is generated to make ammonia in the 1st place.  And we can do that if we’re smart, by using truly green hydrogen in place of black hydrogen.

So- why aren’t we doing that?  Why do we hear almost nothing about projects to make green ammonia to replace black ammonia for use in fertilizers?  Yes, there are a handful of such projects in the works, but most green ammonia projects (or dreams of future projects, which are much more common than real projects) are centred around bad ideas like burning ammonia in power plants, or as a ship’s fuel, or cracking ammonia with added heat at destination to make it back into H2 and N2 again.  Why is that?

One word, one reason:  subsidy.  Perverse and ill considered subsidies generate perverse incentives, and tempting people to use a poison gas as a ship’s fuel is in my view, pretty much the definition of a perverse outcome.

No farmer will voluntarily pay more for green ammonia when their competitors can produce the same crops to sell in the same the same markets with cheaper black ammonia.  And no, a future where green ammonia is cheaper than black ammonia, even with heavy carbon taxes in place but without subsidy involved, is not something that we can expect in the foreseeable future in my view.  While there is hope for something close to cost-competitive to come out of green ammonia projects in the very best locations in the world, the delivered cost will still be a multiple of the cost of black ammonia.  Carbon taxes and emission bans are key, and are much preferable to subsidy.

Petroleum Refining

Petroleum refining is at once the source and the consumer of about 1/3 of the world’s hydrogen.  And both will shrink to about 15-25% of current levels when we stop burning fossils on purpose as fuels.

Hydrogen is used in refineries to remove toxic sulphur and nitrogen species from petroleum cuts that we will later burn- a process known as “hydrotreating”.  The hydrogen ends up as H2S, which is subsequently reacted with oxygen and then broken down into sulphur and water.  Hydrogen is also used in “hydrocrackers”, which not only hydrotreat a petroleum feedstock, but also break large molecules into smaller ones.  When this kind of chain breakage happens, a carbon-carbon double bond is formed in one of the pieces, which is usually undesirable to the final product’s storage stability and usefulness as a fuel.  Hydrogen eases the breakage and also adds hydrogen across that C=C double bond, eliminating the stability problem.

Hydrogen is made in refining or petrochemicals operations such as “plat-forming”, a process by which straight chain hydrocarbons are cyclized and dehydrogenated to make aromatic rings like benzene, toluene etc.  Cracking of lighter molecules such as naphtha or ethane and propane  to make olefins (compounds like ethylene, propylene and butadiene with C=C double bonds, useful for making polymers) also produces hydrogen as a byproduct.

Yes, in a decarbonized future we will still refine petroleum- just 15-25% of what we currently do.  And no, there’s no need to make gasoline and diesel or anything else to burn, in that process.  Whether or not we’ll choose to afford to do what’s required, is another story.

https://www.linkedin.com/pulse/refinery-future-thought-experiment-paul-martin-4pfoc

In summary, petroleum refining will greatly shrink in hydrogen demand, and may end up being nearly self-sustaining in hydrogen in the end (or might consume a small amount of green hydrogen).  Replacing black hydrogen used in petroleum refining today is therefore not a high priority use for any green hydrogen we think we can afford.  We should instead keep the focus on eliminating the burning of petroleum and gas products as fuels.

Everything Else

The other 1/3 of current hydrogen uses is divided among many smaller use cases

Methanol

Methanol today is nearly exclusively made from synthesis gas (mixtures of CO and H2) made from natural gas or from gasifying coal.  In a decarbonized future, any methanol we think we may need to burn- as a decarbonized shipping fuel for instance- we can make either using biomass or using biogenic CO2, the former being much cheaper than the latter.  Both will need green hydrogen- the former because biomass is deficient in hydrogen, the latter because CO2 basically needs to have one of the two oxygens on it “burned off” by reacting it with H2 to produce water.  Green methanol production is a good use of green hydrogen- but we should not reach right away for e-methanol (ie. ultimately made from water, CO2 and electricity) as it will likely be considerably more expensive than bio-methanol with added green hydrogen.

Methanol is also currently used to make many other important chemicals and materials, which are rarely burned- such as formaldehyde, formic acid, acetic acid, certain important polymers, and many others.  Methanol is also used as a solvent and antifreeze agent.

 Direct Reduction of Iron (DRI)

A small percentage of current world iron production is made from iron ore not in a coal coke-fired blast furnace or basic oxygen furnace, but in a process by which syngas (made from natural gas) is reacted directly with iron ore to form iron metal, CO2 and water.  The process, known as direct reduction of iron (DRI) has been demonstrated to be possible using only a very small amount of CO, with almost all of the CO replaced with hydrogen.

It is extremely important to note that iron in DRI is used as a chemical reducing agent (a source of electrons), not as a fuel.  It is also important to note that “steelmaking” is already largely an electric process in the developed world.  For instance, 70% of steel in the USA is made using electric arc furnaces that are fed largely scrap steel plus some fresh iron.  That fresh iron could, in part or maybe even in total, be made by pure hydrogen DRI.

 Since the reaction between iron oxides and hydrogen is slightly endothermic, electric heating is also required (unlike when syngas is used).  The process of DRI using pure hydrogen has been demonstrated at scale by Hybrit and others, and represents the highest technology readiness level (TRL) way we currently have to nearly eliminate CO2 emissions from iron production.  Other options are under development, including molten iron oxide electrolysis and some aqueous electrochemical methods, but all are at a much lower TRL and are at least a decade from at-scale market relevance- if they ever make it to market.

DRI with pure hydrogen is a high value use of green hydrogen, and a potential growth area for hydrogen consumption in a decarbonized future – but only if we do it in locations where both ore and the potential to build new high capacity factor wind plus solar hybrid power sources (or, rarely, excess hydroelectricity) exist close to one another, and nobody nearby needs the electricity that could be sold instead.  Western Australia is a perfect example, but there may be many other such locations- perhaps including Labrador in Canada, and Sweden where H2 Green Steel is building a plant to do just this (using hydroelectricity).

I also see substitutions of iron for aluminum, magnesium, wood and other materials which are easier to decarbonize (i.e. at a lower cost per unit strength) than iron may be.

Other Hydrogen Uses as a Chemical

Hydrogen is used in many other chemical reactions, and as a reagent to prevent others from happening.  It is used to protect metals from oxidation inside furnaces for operations like sintering or bright annealing.  It is used to hydrogenate vegetable and animal oils.   It is used as a coolant in turbines and certain electrical equipment. And it is used in a host of reactions such as making halo-acids (HF, HCl, HBr), hydroformylations and many others.

What We Should NOT use Green Hydrogen For 

Hydrogen’s current use as a fuel is limited to a very small number of specialty uses such as the upper stages of rockets, vitreous quartz “glassblowing” etc.  Notional future uses such as fuelcell vehicle fueling or industrial heating, amount to a trivial fraction of current world hydrogen consumption.

Virtually all the hydrogen currently burned is burned for its energy content and as a waste disposal practice, because it is hydrogen mixed with other gases that are simply not worth the bother and expense of separating from one another.  Despite the recent “hydrogen economy” hyperbole, hydrogen is in fact one of the cheapest commodity chemicals on earth, relatively easily made from methane- a molecule which itself has basically no uses other than for the production of heat energy or syngas.  Hydrogen is really not worth that much- certainly not enough to make it worth sifting hydrogen from a complex gas mixture when there’s a nearby furnace hungry for fuel.  That may change in the future, but it’s unlikely to change much.

Green hydrogen’s role in heating, transport and energy storage is usually a response to the wrong question.  When you ask, “what else can I burn, aside from fossils”, hydrogen is a frequently offered, simpleminded answer. 

But when you ask the better question:  “We can’t burn fossils any more- how can we meet our needs for energy services, without generating fossil GHG emissions?”, the answer is almost never hydrogen.

Making hydrogen from electricity is a step backward in exergy terms- and no, that’s not a typo.  That step backwards has a huge cost associated with it.  One that, I’m sorry, for energy applications, you are very unlikely to ever fix.  You may cope with it out of desperation, breaking your wallet in the process, but that is not at all the same thing.

https://www.linkedin.com/pulse/breakthrough-electrolyzer-efficiency-paul-martin

Green hydrogen’s intrinsic exergy destruction is a feature of its foolish use as a fuel, not a bug.  It’s a systematic inefficiency that acts as a multiplier of all the upstream emissions associated with every unit of useful energy services you generate from hydrogen as a fuel- moving a car by a kilometre, or heating your home, or storing a unit of electrical energy, or what have you.  There are usually better ways- and usually, those ways use electricity more directly, without the exergy destruction resulting from needlessly involving a molecular middleman and its covalent chemical bond formation and breakage.

https://www.linkedin.com/pulse/how-green-hydrogen-lifecycle-basis-paul-martin-pbhyc

But we’re not done yet- hydrogen has the twin problem of being energy and especially exergy inefficient, but also being ineffective as a fuel.  It is difficult to move and store.  That kills hydrogen as a practical replacement for some applications which are also not suited to electrification, such as transoceanic shipping and aviation.  Those applications will need liquid fuels, and those liquid fuels will be much cheaper to provide as biofuels.  Green hydrogen’s role there will be limited to yield improvement, as we’ve already discussed in relation to methanol.

Finally, those few applications for high temperature industrial heating that truly need fire rather than just heat, are rarely a good fit for hydrogen due to its lack of an emissive flame.  Biofuels are a better solution for those applications too.

Evidence

Michael Liebreich has provided a very useful graphic which shows that the highest value uses of green electricity are via the “electrification pathway” in every case where hydrogen is considered as an alternative. And where electricity needs to be made greener, it is far more sensible and economic to do THAT, than it is to try to use that same electricity to produce green hydrogen- even to replace black hydrogen in uses durable post decarbonization. Hence, the famous Drake meme well and properly deserved modification. This point should go without saying, but needs to be said- loudly and often.

Conclusions

It really is as simple as the meme.  Green hydrogen should be reserved for applications requiring its special properties as a molecule, where its resulting emissions are absolutely without regret.  It should not be wasted as a fuel.  And anybody selling you the idea of using hydrogen as a fuel, is selling you a bill of goods- sometimes out of ignorance or poor analysis, but often as a result, at least in part, of the fact that they have an invoice waiting for you in their back pocket- and some of that invoice’s proceeds are headed to their own bank account.  That’s not always true, to be clear- there are some true believers in hydrogen as a fuel who literally have no money riding on it.   But it was true frequently enough that myself and a number of co-founders saw fit to build the Hydrogen Science Coalition, to provide insights about hydrogen’s true role in decarbonization, from a position of scientific and engineering knowledge, free of any significant financial interest one way or another.

Disclaimer:  this article was written by a human, and humans are known to make mistakes from time to time.  Let me know, with good references, where I’ve gone wrong, and I will correct my work with gratitude.

If however what you don’t like is that I’ve taken a dump on your pet idea, then please feel free to contact my employer Spitfire Research Inc., who will be most happy to tell you to piss off and write your own article.

Yes, Virginia, Solar Really is THAT Cheap!

TL&DR Summary:  yes, it really is that cheap.  It’s not bullshit.  It’s real.  And it’s going to power the world.   Well, not the whole world- but a very significant part of the world.

Those of you who read my articles will know that I have a small farm east of Toronto.  We’ve built a couple small cabins there, and repaired a dilapidated building to become my workshop.  There’s no well, no septic system, and no grid electrical supply.   No, we don’t live there full time- but it does serve as a useful test bed for an off-grid system regardless.

Our power solution is pretty simple:  we have solar, and in the few winter weeks where solar is interrupted by snow cover on the panels, we have a gasoline generator.  That generator runs more often just to make sure that it works when we need it, than it ever does to make power.

Each cabin has a single panel, a small charge controller, a 300 W inverter (good enough for lights, a fan in summer, and cellphone charging), and a battery- generally an 80 Ah marine lead-acid battery, because they are best suited to sitting full most of the time.  The breakdown of the cost of these systems is as follows:

(all costs in this article are in $CDN, not including taxes.  As of publishing, the $CDN is about $0.75 USD)

12V 100W panel:  $100 (Amazon) – you can get a more powerful 30V panel but then you need a better charge controller

PWM charge controller:  $10 (AliExpress) Want a MPPT unit that can handle a higher voltage panel?  Then you’re looking at $100

300 W 120 V inverter:  $30 (AliExpress)

Wire and connectors:  $50

80 Ah lead-acid marine battery:  $200 (Canadian Tire)

Why bother with these little systems at all?  Because the cabins are a long way from one another, and stringing wire through the woods is a pain in the butt, and ruins the aesthetic.  Trenching is even more of a pain, and would sever the roots of numerous trees if we did.  And a single panel and battery produces all the power we really need, with no ongoing operating costs other than some distilled water every once in a while to water the batteries.

You’ll note that the biggest cost in each of these systems is the battery.  While “lead is dead” for real solar applications that cycle frequently or deeply, lead-acid’s one strong point is applications needing to sit at 100% state of charge for long periods of time, where discharge is at a low drain rate (low currents, draining the battery over a period of 20 hours or more).   The capacity of lead acid batteries at high drain rates is very low due to the Peukert effect.  Lead-acid batteries love to sit full, and need to occasionally be agitated to prevent sulphation- that’s why they last so well as vehicle starter batteries. In stationary applications, agitation is normally done by means of a “balance” or “equalization” charge cycle, where overvoltage is applied and the cell electrolyte is agitated with the resulting hydrogen. 

If we ever need more power- to run power tools at one of the cabins for instance- we have a brick of four LFP prismatic cells with a 3000 W inverter mounted on top of it.  This is our “silent generator”, and I use it for all my mobile construction projects.  We recharge it using a DC/DC converter ($6, AliExpress) from the main pack in the workshop.

The workshop system is more complex, and more fully functional as a source of electricity.  It consists as follows:

Four nominal 300 watt panels:  I recently bought two 320 W Jinko panels for $135 each.  These are brand new, just the older model.  $0.42 CDN per watt of capacity…that’s insanely cheap.  Total $540 for 1.2 kW of nameplate capacity.

Mounting structure:  made of 2x4s sawn from fallen trees in our own forest. Previously, the other two panels were mounted on two ~ 4” diameter black locust trees that I had to fell because they were in the wrong place, which I just limbed, notched, and leaned up against the south side of the building (back during COVID when 2x4x8s were $10 each).  It looked ugly and worked just fine, but now I have a nicer support system which allows me to tilt the panels to different angles in summer and winter.   The structure cost me perhaps $10 worth of hardware and $10 worth of sawmill and chainsaw gasoline and tractor diesel and sawblade wear and tear combined, but if you bought the wood at Home Depot it might have cost $125 or so.  The exercise I received is not charged for, but saves a gym membership.

Charge controller:  EPEVER 40 A maximum power point tracking unit with buck stage, $200, Amazon.  These things are pretty brainless and still don’t have proper factory lithium ion settings, but you can make them work especially with a BMS. 

Batteries:  eight 280 Ah LFP prismatic cells:  $860 including delivery from China.  These cells are guaranteed for 6000 cycles, and are about 90% efficient, i.e. they return 9 out of every 10 kWh you feed them.  They come with the cell connectors to build a series pack.  I built a box for them out of leftover plywood.  The eight cells are arranged in series with a total nominal capacity of about 7 kWh.

Battery Management System:  depending on what you’re doing, these can cost between $20 and $200 for a suitable unit.  The 100 A 24V unit I am using at the farm cost $60 (AliExpress).  The BMS monitors individual cell voltages.  If any cell goes above 3.65 V, it shuts down charging.  If any cell goes below 2.5 V, it shuts down the inverter output.   The BMS also provides a shunt charging balance function to top-balance the cells, but with LFP such continual balancing is basically unnecessary.

Battery Status Gauge (“smart shunt”)- $60, Amazon  (not strictly required, but helpful to know your state of charge, which with LFP cells you simply cannot tell via voltage readings except below 10% and over 90%).  This device measures and displays currents into and out of the cells and keeps track of the battery state of charge.

Inverter:  3000 W peak (1500 W continuous) true sine wave unit, 24V nominal input $108 (AliExpress)

Miscellaneous:  wire, connectors, disconnects, terminals etc.:  perhaps $200 all in

Ignoring my labour (and why shouldn’t I- this was all good fun!)  that’s about $2000 for the whole shebang.  That’s not just solar, but also includes storage.  More than enough storage for our needs- but we’ll soon have even more, as I augment the existing pack with batteries taken out of my electric car conversion projects after 10 years of service.  At the lower C rate of a solar application, these LFP cells will likely last ANOTHER ten years.

Some of you will say, “Oh, isn’t it nice to be an engineer, to know how to do all this stuff?!”  Well, I’ve got one word for you:  YouTube.  Visit one of the numerous sites such as Off Grid Garage, and you’ll soon know what’s involved.  It ain’t rocket science, or brain surgery, much less rocket surgery!  As long as you stick with either lead-acid or LFP with a BMS, and stay at 48V or less, you’re going to be just fine.  And yes, you can pay more for simpler solutions- LFP batteries packaged with their own internal BMS for instance so you don’t have to trouble yourself over them any more than you would with a lead-acid battery.  You can always push the “easy button”- it just costs you a bit more.  Of course you could push the “more money than brains” button and buy a Tesla Powerwall, but I definitely wouldn’t recommend that!  That product is massively over-priced.  Think of it as the “Apple” of battery storage systems.

How much electricity can my workshop system produce in a year?  Well, the panels will generate about 1,300 kWh per year per kW of installed capacity, so about 1,560 kWh per year.  And yes, they generate a surprisingly large number of kWh in winter, despite the snow- tilted at the correct angle, they tend to shed snow surprisingly well.  But of course I won’t use all of those kWh, so it’s hard to make a proper cost comparison.  In summer, most of the kWh go to keeping a fridge and freezer cold while we’re not there- but it’s nice to have cold drinks and to not have to go into town every time you need something.  In winter, the system more or less does nothing when we’re not there. 

The important thing is this:  the system is sized for our winter needs.  In summer, we make excess kWh but they cost us nothing.  When the batteries are full, the charge controller or the BMS simply disconnects the panels.  The cost of curtailment is zero.

But when we’re there, that system does everything we might expect to do with a power line connected to the grid.  If we lived there full time, we’d likely go up to 10 kW of panels (because they are VERY cheap) and quadruple our battery storage too, going with higher output hybrid inverters etc. etc., but that would be more about convenience, reliability, and recharging our electric car, than about anything else.  That system would definitely be up to the job of running a heat pump for cooling and shoulder-season heating.  We’d still heat the place primarily with wood, because with 28 acres of woodlot, we could never burn all the deadfall.

Costs per kWh and Other Metrics 

You could perhaps add up 16.5 years worth of the panels’ production (daily cycling of the batteries to achieve the guaranteed 6000 cycles takes 16.5 years- the panels etc. should all last much longer than that) and do a ratio, i.e. $2000/(1,560 x 16.5) kWh = $0.08/kWh, but that would assume that I use every kWh I make.  

Remember, that includes storage.  That’s for fully functional solar power.

But a better comparison is this:  what else can you buy for $2000?

You can buy the installation of one (1) power pole.  And I’d need fourteen (14) poles installed to bring power to my site from the nearest utility pole.  That doesn’t include wire, or labour to install it.

You can buy 4.5 years worth of monthly account charges to have an account with the local electrical utility, whether you use any kWh or not…

Are you agreeing with me yet?

Solar power is just that cheap.  Solar plus batteries are of course even cheaper in Australia where capacity factor is such that each kW of panels generates 2.7 times as many kWh per year, and where snow cover on the panels is never a worry. 

And panel and battery prices are still falling- as are the prices of all the various bits of kit needed to build an off-grid or “behind the meter” system.  Sodium ion is just coming on stream now, and has the twin advantages of low materials cost (nothing in those batteries is anything other than earth abundant), and the ability to be shipped fully discharged, i.e. no hazardous goods shipping charges, which are a significant fraction of the cost of buying LFP cells today.

I can clearly see where this is going.  I’ve seen it for years now.  Can you?

Yes, I know that my own little system isn’t a pin for pin replacement for the grid connection you have to your house, condo, flat, or castle.  I know you “can’t” and really wouldn’t build a whole grid like this.  I know there are reliability needs that literally mean life or death, that must be satisfied.  I know every human in a developed country is now conditioned to think that power can be supplied in any quantity with no more thought than it takes to flip a switch.  I know that building a fully decarbonized energy system is going to take decades, and cost trillions, and require major changes to how consume energy and hence how they live.  But if you don’t see that solar is going to play a major role in energy supply in a decarbonized future, I’m sorry- you either haven’t thought about it carefully enough or you’re delusional.  Energy this cheap is just too good an opportunity to pass up.

Disclaimer:  this article was written by a human, about his own little experiments with solar power.  If I’ve made a mistake, as humans are wont to do from time to time, correct me and I’ll be grateful.

If however you don’t like what you’ve read because I’ve threatened your own pet idea, then you can contact Spitfire Research Inc. who will be more than happy to tell you to piss off and write your own article.

How Green is Green Hydrogen on a Lifecycle Basis?

Image source: Google Gemini. Gemini won’t draw people, i.e. sketchy looking men in business suits, so I asked it to draw “a robot similar to Bender from Futurama”, and that did the trick. Worried about copyright? Suggest you talk to Google.

TL&DR summary:    a recent paper published by Dutch researchers in the journal  Nature  Energy (K. de Kleijne et al, May 28 2024,  https://doi.org/10.1038/s41560-024-01563-1, evaluated lifecycle emissions from around 1000 projects in the IEA Hydrogen Projects Database.  Making best efforts to estimate the real GHG emissions associated with renewable electricity generation, battery storage (if required to obtain high enough capacity factors), electrolyzer manufacture and (negligible) water treatment, the median green hydrogen project of the optimal configuration (“islanded”, but with excess renewable electricity being fed to the grid) of 2.9 kg CO2e/kg H2 (range of 0.9 to 4.6 kg CO2e/kg H2).  Adding 1000 km of pipeline transport- the cleanest option- added another 1.5 to 1.8 kg CO2e/kg H2.  Whether or not that should be considered adequately “clean” hydrogen, depends greatly on the use case for that hydrogen- a topic the authors of the Nature paper simply did not consider.

A recent paper in Nature Energy (reference above) made a valuable attempt to answer the question:  how green is green hydrogen, really?

Most green hydrogen project assessment tools assume that the GHG emissions associated with renewable electricity generation are zero.  And that, clearly, is a bad assumption.  All electricity generation processes including wind and solar, have GHG emissions associated with both the production of the initial generation equipment, and with ongoing maintenance.

The authors looked at over 1000 projects in the IEA Hydrogen Projects Database.  Most of these were green hydrogen projects, meaning projects putatively using renewable energy (wind, solar or hydro generally) to make hydrogen from water via electrolysis.  Projects using nuclear electricity as well as projects making hydrogen from methane, i.e. the good old-fashioned, high emission way which really should be called “black hydrogen” but which the industry euphemises as “gray”, with and without carbon capture and storage (CCS), are also used for reference.  Methane emissions varying from 0.5% to 8% for the natural gas source are considered, but the likely comparator basis is the 100 year time horizon for methane (i.e. global warming potential for methane of 33x that of CO2).

The authors grouped green hydrogen projects into four basic production scenarios:

  1.  Off grid (i.e. “islanded”) production, with new (additive) wind and/or solar built out at 2x the electrolyzer’s capacity, with a Li ion battery storing about 25% of the electricity where necessary to achieve an electrolyzer capacity factor of between 0.4 and 0.6.  These projects had median emissions of between a little over 1 kg CO2e/kg H2 for offshore wind, to about 7.5 kg CO2e/kg H2 for a pure solar project.  In each case, the majority of emissions was from electricity production, with excess electricity being curtailed.  In each case the emissions associated with battery and electrolyzer production were small, on the order of ~0.5 kg CO2e/kg H2 at most.  The rest was electricity related emissions.  And with hydrogen taking on the order of 50 kWh per kg to produce via electrolysis, you can see that even very small emissions from electricity, add up rapidly per kg of H2. 
  2. Grid connected with power export:  this assumes that the local grid absorbs excess renewable electricity when it is beyond the electrolyzer’s capacity to use it, exporting it to the grid where it decreases local grid CO2e intensity by the difference between the average grid CO2e intensity in that country or region, and the intensity of wind/solar per kWh in that region.  This of course assumes that other, non hydrogen-related grid connected renewables projects haven’t already saturated the grid’s ability to absorb and use their peak production.  The credit for the exported electricity reduces CO2e intensity to about 0.8 for offshore wind to a little over 4 kg CO2e/kg H2 for solar
  3. Grid connected, with grid power import:  this one is a real stinker, with GHG emissions associated with imported grid electricity totally swamping the benefit of renewable energy use.  Emissions here ranged from over 6 to over 16 kg CO2e/kg H2.  Note that this is despite the renewable electricity being used, being “additive” (new to the grid).  This is the shell-game that most green hydrogen projects in the US and Canada are trying to pull off, using “power purchase agreements” with other renewables suppliers to make up their own local shortfall in production, despite the fact that the power will be delivered to them via the grid- and that the grid has a certain carbon intensity.  It seems, to me at least, that the all important factor of “temporal matching” between renewables generation and electrolyzer operation, never had a better piece of evidence in favour of it than this work!
  4. Configuration-independent applications, including using nuclear electricity (results are low GHG green hydrogen below 2 kg CO2e/kg, but utterly unaffordable in any electricity market on earth.  Another considered was an electrolyzer running at 5% capacity factor (again, utterly unaffordable), but using only renewable electricity that would otherwise be curtailed which is then given an intensity of 0 kg CO2e/kWh.  The result is very clean but very unaffordable hydrogen.  Hydroelectric hydrogen has a CO2e of just over 2 kg CO2e/kg, while grid electricity used to run electrolyzers has an eye-watering intensity of over 21 kg CO2e/kg, making even black (gray) hydrogen without CCS look favourable in comparison

The work is interesting, and carefully done, with good references.  It’s a shame they didn’t give ranges for the CO2e/kWh for wind and solar that they used, but they gave formulae from a reference LCA paper which relates these figures to wind speeds and solar irradiances, which vary greatly by location including for a variety of types of PV panels etc.

All of this of course gets worse when you add hydrogen distribution.  Pipeline distribution is most efficient, with CO2e additions of about 1.2 to 1.5 kg CO2e/kg H2 for a pipeline of 1000 km.  Liquid hydrogen and ammonia, even without ammonia cracking back to hydrogen at destination, are much worse than that due to largely energy losses in interconversion and transport.

Major Conclusions

It appears that although many of the projects, even on a proper full LCA basis per the authors’ work, even assuming uses for the product hydrogen immediately on-site, give CO2e/kg figures sufficient to meet the minimum requirements for subsidy under US IRA, EU and UK rules, most projects don’t make what the Hydrogen Science Coalition would consider to be “clean” hydrogen of 1 kg CO2e/kg H2.  The HSC clean hydrogen standard is based on the CO2e intensity for hydrogen production required for the world to meet the stated 2050 emission reduction goals (i.e. “net zero” by 2050). 

The reason for the high carbon intensities isn’t that green hydrogen projects are burdened with heavy embodied emissions for either the electrolyzers or for batteries (the use of which is questionable in this study).  Both add a little- but the big killer is electricity production and its associated emissions.  

Grid electricity to raise capacity factors is obviously a bad deal.  While economically imperative (because electrolyzers are too expensive to operate at low capacity factors), grid electricity simply blows out the resulting hydrogen’s CO2e intensity to an absurd degree on most grids in the world.

While export of excess green energy to the grid has been shown in this work to reduce the effective CO2e of the product hydrogen, the ability of the local grid to usefully absorb this electricity- which would be made in excess by any grid connected project without an electrolyzer during the exact same periods of time- is just taken as a given.  This will not be true in most places, especially as renewables are rolled out to a greater and greater extent.

Another surprising result is that local hydrogen production is nearly always lower in GHG emission than green hydrogen made in locations with better access to wind and solar- if those locations require hydrogen transport by anything other than pipeline, or even by pipeline of longer than about 1000 km. 

What the Authors Missed

In the paper, use cases for the product hydrogen are absolutely ignored.  The preamble talks about the necessity of and plans for green hydrogen to expand in production and to become a trade commodity etc.- the usual #hopium laced hydrogen economy hyperbole.  What is not discussed is the CO2e per kWh of useful energy services delivered to destination, relative to other options.

When green hydrogen is following my Drake meme, and being used to replace existing uses of black (gray) hydrogen which require hydrogen’s unique chemical properties and which are durable post decarbonization, it can be said that such green hydrogen is “no regret”. 

The only appropriate metric for such hydrogen is against the hydrogen it replaces- black (gray) hydrogen, made for instance from natural gas with methane leakage accounted for. Such hydrogen ranges from 12 to 18 kg CO2e/kg H2, depending on methane leakage rates and whether you use the 20 or 100 yr GWP of methane relative to CO2.  Even reducing the 14 kg CO2e/kg hydrogen generated, optimistically, from natural gas in Alberta, for instance, to about 12 kg CO2e, as the blue (bruise coloured) Shell Quest project does by doing partial CCS, is arguably OK- though the cost per tonne of CO2e emissions averted is ridiculously high-if the hydrogen is used for things like ammonia or methanol production, direct iron reduction, food oil hydrogenation etc. etc.- things that we’ll still need to do post decarbonization.  Not so for Quest- it’s used to desulphurize and hydrocrack fossil tarsands bitumen, which we will simply stop doing post decarbonization, preferring to make chemicals and materials out of lighter, sweeter crudes better suited for the task.

The Refinery of the Future

But when green hydrogen is to be wasted as a fuel, whether for transport or heating, the appropriate metric is what we could do instead to deliver those energy services.

For transport, the appropriate metric isn’t against fossil fuel use, but against the use of the same electricity to charge battery EVs.  And we all know, or should know, that on that basis, BEVs are simply going to blow hydrogen to smithereens in terms of kg CO2e/100 km driven.  But since you a) are smart, and don’t believe what people tell you just because they sound credible and have a bunch of unkempt gray hair (i.e. people like me!), you want some numbers:  so here are some numbers.

Going back to my paper comparing the Toyota Mirai Mk 1 against the Tesla Model 3 long range version,

https://www.linkedin.com/pulse/mirai-fcev-vs-model-3-bev-paul-martin

EPA range for the Tesla was 334 miles and for the Mirai was 312 miles.  To go 312 miles, the Mirai uses about 5 kg of H2.  Assuming the median H2 emissions from this study of 2.9 kg CO2e/kg H2, that’s about 2.83 kg CO2e/100 km if green hydrogen were used, ignoring distribution losses for the moment for both the H2 and electric car.  The Tesla, on the other hand, uses 260 Wh/mile or 86.8 kWh (from the wall, including charger and battery polarization/ohmic losses- 75 kWh from the battery pack).  That’s about 15.9 kWh/100 km.  To equal the GHG emissions of the Mirai, the local grid intensity would need to be  2.83 kg CO2e/15.9 kWh, or 178 g CO2e/kWh.  There’s no way renewable electricity has anything close to that high a carbon intensity- local GRID CO2e here in Ontario is about 40 g CO2e/kWh.  So unless you are comparing a GRID recharged EV to median renewable only green hydrogen production, you can see clearly that the BEV is the clear winner.  Its greater energy efficiency necessarily reduces GHG emissions from operation of the vehicle, and it is also clear that operational emissions over a norma vehicle’s live, positively dwarf the embodied emissions from making the vehicle- even one with a large 75 kWh battery pack. (note: fuelcells and 700 bar composite hydrogen tanks are not low in embodied emissions, either)

Looking this time at heat:  1 kg of H2 with a CO2e of 2.9 kg, has a higher heating value of 39.4 kWh.  Feed that to a 95% AFUE boiler or furnace and you’d get about 37.4 kWh of heat into a home, again ignoring hydrogen distribution losses and emissions.  We could instead feed 12.5 kWh of electricity to a heatpump with a coefficient of performance of 3, to do the same job.  2.9 kg CO2e/12.5 kWh would be even higher- 232 g CO2e/kWh- way too high to be of renewable origin.

Electric heat pump vs hydrogen boiler heating for the UK, an energy chain comparison (source David Cebon, Hydrogen Science Coalition)

When we consider feeding the very same electricity to these end use cases that would have been sent to the green electrolyzer- you get the picture.  There’s no comparison.  Direct electrification wins, hands down.  And no, the storage feature that hydrogen proponents want to hang their hats on, simply isn’t worth those extra use case emissions when hydrogen is wasted as a fuel or deployed as a long distance energy carrier, either directly or in the form of a so-called e-fuel.

Disclaimer:  this article was written by a human, and humans are prone to making mistakes.  Where I’ve made a mistake, please provide good references and correct me, and I will correct the text with gratitude.  I care more about getting the issues right than about being right myself.

If however I’ve upset you by pissing on your pet idea, then please contact my employer, Spitfire Research Inc., who will be more than happy to tell you to piss off and write your own article.

The Refinery of the Future

photo credit: Google Gemini

TL&DR: we will continue to refine petroleum to make the chemicals and materials we need in a decarbonized future. We’ll just do it without the burning. It will be complex, expensive, and will take a new kind of refinery which looks quite different than today’s refinery.

You’ve no doubt heard the nirvana fallacy argument common among fossil fuel lovers, climate change minimalists and climate doomers alike: that when we give up burning fossils as fuels, we need to be prepared to give up the tens of thousands of materials and chemicals we make from fossil petroleum, gas and coal, because producing them is impossible without making fuels.

Those people are either talking out of an orifice best reserved for something other than talking, or they’re really saying they don’t know how we’d keep using petroleum to make chemicals and materials without making fuels. You shouldn’t listen to them. They’re wrong.

I’ve spent decades helping people develop and test alternative ways of making chemicals and materials from both petroleum and biomass, so I know a thing or two about this topic. However, this is a huge area of chemical process technology and no one living human knows it all. I’ve got a pretty good overview though, so I thought I’d take a stab at imagining what a future petroleum refinery would look like.

No, We Won’t Use Biomass Instead

There are some who see no path forward other than transitioning the entire carbon economy to start with biomass. As someone intensely familiar with making chemicals and fuels and materials from biomass, I can say that this will be a fairly small fraction of the future refinery.

Biomass, every sort of which was recently CO2 in the atmosphere, is “carbon neutral” insofar as we don’t make any fossil GHG emissions along the value chain. Today’s agriculture is very fossil based, with nitrogen fertilizer and farm fuels, grain drying and transport all more or less 100% fossil based. We’ll need to transition substantially all of that away from fossil fuels use and that’s a huge separate task. Agriculture also generates new, un-natural emissions of methane and N2O, both potent GHGs. We’ll need to cut that out as well, by more strategic fertilizer use, genetic engineering of soil organisms, and much, much better nutrient management.

There are a handful of materials of the chemical variety that make sense to make from biomass. Some of them we make already. Others are virtuous substitutes for fossil derived chemicals. But a mass shift from fossil petroleum to biomass sources for chemicals and materials is extremely unlikely in my view.

Why is that? Simple. Biomass has an average general chemical formula of C6 H10 O5. There are exceptions- food oils being one example- but the greatest mass of biomass is cellulose and lignin, not vegetable oil. It is hydrogen deficient, and worse still, there’s nearly one oxygen atom for every carbon atom. To make most useful chemicals, those oxygens need to be removed by reacting them with hydrogen to produce water, or burned off to produce CO2. Both represent a huge loss of energy and mass.

What will we do with biomass? We’ll make shipping and aviation fuels. We may need some green hydrogen, made from water and renewable electricity, to satisfy our hydrogenolysis needs. But all the CO2 that goes back into the atmosphere from these applications, which need liquid fuels, will have been in the atmosphere in the recent past. Making fuels from biomass is far easier than making anything else of value.

We Won’t Use Direct Air Capture (DAC)

DAC is thermodynamically and economically FUBAR. IT isn’t a real technology, it’s a predatory delay strategy, intended to keep us burning fossils for longer, guilt free. No, we won’t be snatching CO2 out of the atmosphere and reducing it chemically using green hydrogen to make chemicals or materials. There are far better sources of CO2 for the handful of chemicals it makes sense to make from CO2, like formic acid, formaldehyde and perhaps methanol. Just get “chemical carbon recycling” out of your head- it’s not going to be a thing.

The Refinery of the Present

The original oil refineries were simple batch retorts where oil was put into a container and heated, the vapours taken off the top and condensed, heating continued until no more vapours came off, and then the pot was cooled and the remaining tar or char was dug out with picks and shovels. And the original high value product was kerosene for lighting. The lighter fractions were thrown away, often into local rivers and streams.

Gradually, the heavier oil fractions became useful as a replacement for coal in steam engines. Tar had uses in roofing and waterproofing. But over time, as engines developed, the lighter fractions found use too, in gasoline and diesel engines. The lightest fractions were still burned as fuel gas to run the distillations.

Eventually the lighter fractions came to dominate demand as the internal combustion engine took over transport from the horse and the steam engine. And large sources of heavier oil were found. Crackers were soon invented, and cokers too, to break big molecules into more valuable smaller ones.

Soon a host of refinery operations were invented. New fluid catalytic crackers which efficiently made olefins (molecules with C=C double bonds) useful for plastics and to make larger molecules of the right type and size, but which also converted heavy oils to lighter fractions . Alkylators to put branches on chemicals. Plat-formers to turn straight chains into rings and hydrogen. Hydrotreaters and hydrocrackers to remove sulphur and nitrogen, using hydrogen generally made from natural gas. Cokers and extinction hydrocrackers to convert the very bottom of the barrel- the tarry junk called residuum or “resid” which doesn’t boil at 300 C and 1/760th of an atmosphere pressure- into petroleum coke and a little more of the good stuff. And every fraction along the way gets split off to another unit, reacted, converted, or sold off to someone else for further processing. Small molecules get bigger, and big ones get smaller all over the place. The refinery can change its suite of products by adjusting both feedstock blends and turning various knobs in the process.

Refineries are highly integrated, with major petrochemical producers having their plants nearby. Many are specialized around certain feedstocks- some take light oils, some specialize in heavy oils. Byproducts are recycled or burned as fuel gas. Heat energy is recovered from one step to use in another, or made into steam to run turbines to run pumps, compressors or to make electricity. The scale is giant, and most of the time, margins are quite thin. Big refineries therefore find it easier to consistently make money than little ones, because they have lower capital intensity due to greater economy of scale.

How Much Do We NOT Burn?

It varies a lot, but only between 15% and 25% of a petroleum refinery’s output is used to produce things that are not fuels. 75-85% ends up being burned at some point. When you take into account the fact that petroleum discovery, production, refining and distribution is about 81-83% efficient, meaning that 17-19% of each barrel is used between the well and your gasoline tank, the fraction used for truly high value uses seems even smaller still.

The Refinery of the Decarbonized Future

As mentioned already, petroleum refineries are incredible machines which make small molecules bigger, make big molecules smaller, and change the shape of molecules in profound ways as a routine part of making the suite of products we need today. And petroleum refineries have evolved to make a differing suite of products over time, as market demand and oil supply sources have both changed profoundly.

How on earth could we cope with making only 15-25% of the current products, and not making the rest? To some that seems just ridiculous and impossible, hence the nirvana fallacy argument mentioned at the start of this piece. But not to me. Not to anybody who understands the unit operations and chemistry.

All that would change is two things:

1) Energy sources: whereas current refineries burn byproducts and natural gas to make the heat necessary to run the various processes, the refinery of the future will do this with electricity.

2) Garbage disposal: fire (boilers and fireboxes on various units) and certain low value fuels, are both the current catch-all for mixtures of molecules that the refinery doesn’t need and which don’t fit the product specification of higher value products. That will need to end.

Wow, those are NOT small things that need to change! But they’re a far cry from impossible.

Getting Rid of Fire for Heating

Electric heating is by and large a no brainer. The only reason we use fire today is that we’ve been making all the heat we need via fire for the past 800,000 years- and in past we also made most of our electricity from fire. But electricity is pure thermodynamic work- it can easily be used to either pump heat or to make heat at any temperature or conditions desired. All we need is to stop treating the atmosphere as if it were a free and limitless public sewer, and all of a sudden there’s a value proposition for smarter ways to make and use heat.

Many unit operations such as distillation are a prime example of how we can be smart about this. In a refinery, the waste heat from one step is often used to provide heat for another, either directly by heat exchange or indirectly via steam generation and use- we’ll keep doing that in the future too, but we have another knob to turn. In a distillation unit, nearly every joule that goes into the reboiler, comes back out of the condenser, just at a lower temperature. By compressing the vapour to raise its condensation temperature, the reboiler heat exchanger can become the condenser. The coefficient of performance of this type of heat pumping, called mechanical vapour recompression, can be very high indeed. We just don’t do it often today because fuels and cooling water are both really cheap.

But where heat pumping schemes aren’t possible, electric heating of various sorts, from resistance heaters to inductive, microwaves and plasma arcs, can substitute for fire. And they are easier to control than fire, and usually generate no flue gas which needs heat recovery before discharge.

I designed and built dozens of pilot and demonstration scale plants for a dizzying array of refinery, chemicals and materials processes. Only one of those units ever deliberately used fire to make heat. All the rest was done electrically, because at small scale, fire is dangerous, difficult to control, and not worth the energy cost savings. As time goes on, scaling up electric heating will require some brainpower, but it’s not rocket science, or brain surgery, much less rocket surgery!

The Alternatives to Fire for Waste Disposal

An old movie quote from whoknowswhere rings in my head: someone asks “how will we sort the guilty from the innocent?”, to which the madman, soldier or action hero replies, “Kill ’em all and let God sort ’em out!” That’s more or less what we do with complex light hydrocarbon mixtures in the refinery, with God replaced by fire. Everybody, the valuable and the valueless alike, are reduced to their fuel value.

Numerous unit operations generate continuous streams of light gas molecules. Others generate such streams intermittently, from cleaning, de-coking or catalyst regeneration steps. Often, these gas mixtures contain water vapour, nitrogen, carbon monoxide, CO2, hydrogen, and a mess of light hydrocarbons with low economic value. The logical solution is to just burn the mixture to satisfy the enormous energy thirst of the refinery.

That too must end in the refinery of the future.

And it must end in society in general. We have to stop burning fossils, and that doesn’t just mean petroleum, natural gas and coal- it means everything made from them. Europe, for instance, will need to stop burning municipal solid waste because of its waste plastic content. Waste plastics will need to be recycled or landfilled instead.

Why? Because the product fossil CO2 from burning has only two possible destinations: carbon capture and storage, or “un-burning” (reversing combustion) using hydrogen, green or byproduct of the various refinery operations, to produce water and reduced hydrocarbons like CO or methanol- and then only for uses which are themselves not burned at end of life. Both are unpleasant and expensive.

Some CO2 generation in the refinery will be inevitable, so some “un-burning” or CCS will be inevitable. But making it worse by burning stuff instead of sorting the molecules would be a decidedly bad idea.

So: we’ll need to get into the molecule sorting business, big time.

Some companies are already doing this. They’re like urban racoons, sifting through the garbage disposal called the fuel gas system, hunting for valuable molecules like hydrogen or ethylene, burning the rest. Membranes, absorbents and other technologies can be used to do this, though it takes energy and money.

And we’ll also need to feed those light molecule mixtures to reformers, and then use, ***gasp- I never thought I’d say this!***, a total pile of steaming sh*t of a process called Fischer Tropsch, or F-T for short. F-T can also be understood as standing for “f*cking terrible”. It’s a process by which CO is hydrogenated to make hydrocarbon molecules and water:

CO + 2H2 ==> -(CH2)- + H2O

The CO and H2 are made from fossils by reforming:

nCH4 + mH2O + heat (i.e. more CO2 emissions) ===> xCO + yCO2 + zH2

F-T has been around for a long, long time. It was made popular by the Nazis when their oil supplies were short, as a way to make gasoline and diesel from coal, the coal being gasified to produce CO and H2 and CO2. And then another bunch of people who found themselves embargoed by most of the world for their unsavoury treatment of their own population on the basis of the colour of their skin, did the same thing in South Africa. You’ll note the theme here: ain’t nobody does F-T unless they’re f*cked otherwise, i.e. they have no other choice. Fascism, racism, genocide etc. are fortunately optional.

Why is F-T so terrible? Lots of reasons. But the biggies are its very poor energy efficiency, super-high carbon (GHG) intensity, lack of selectivity to molecules of the size you want, and ridiculously high capital intensity- which gets worse and worse the smaller you make the plant.

As an aside: anybody thinking they’re going to run F-T on syngas made from either CO2 and green hydrogen, or from biomass and green hydrogen, is just an idiot. Don’t listen to them and make sure you keep your wallet securely away from their hands’ reach.

Other than the Nazis and the South Africans, F-T has been deployed a few times successfully-ish. The key plant is Shell Pearl, a mammoth $24 billion (over a decade ago) project in Qatar. This plant eats basically free natural gas for power and feedstock, that the Qataris have in giant quantity with no other use for. It spits out high quality waxes and base oils for lubricants, plus the usual range of fossil fuels (LPG, gasoline and diesel fractions) that a refinery puts out- just nice clean ones with no sulphur or nitrogen or metals in them. Those either aren’t found in the natural gas feedstock or are removed in the syngas production process. That said, despite free feed and energy, mammoth vertical scale, and a giant atmosphere to dump the waste CO2 into for free, if petroleum isn’t selling above $40/barrel, Pearl reportedly cannot make money. That’s probably $60 in today’s dollars too, and will climb as carbon taxes climb.

F-T fundamentally makes a range of molecular weight products. If you don’t want waxes (because their market is small, and you don’t want to pay to hydrocrack waxes back to molecules of a size you really want), you end up making syngas (which you made from methane usually), back into methane and light molecules of the LPG range. The process basically reverses the process used to make its feedstock- and that simply cannot be stopped. (as an aside- the Sabatier reaction is basically the result of totally breaking a F-T catalyst so it makes nothing but methane). Those light molecules, if derived from fossil CO or CO2, are nearly useless in a decarbonized future, so you’ll need to recycle them to the reformer for another go-round, wasting energy and capital. And if you don’t want methane and LPG, you’re out of luck- you’re always going to make some, even if you turn the molecular weight knob up to 11 and force it to make as much wax as possible.

Yes, people claim to have fancy F-T processes and catalysts which make a narrower molecular weight distribution, and it’s true. But they all come with extra capital cost or other problems- and none of them avoid both LPG and waxes.

So- why would we reach for this fundamentally broken piece of tech? One reason and one reason only: it sucks less than burning plus CCS, especially if you can make hydrogen cheaply enough. It allows you to make molecules that you can recycle back into the refinery and convert to products.

You would probably put a methanol plant on there too. Methanol is the one process which can take CO2 (plus H2) as a feed and not just become economically craptastic as a result. The reason is that the methanol synthesis catalyst is a water-gas shift catalyst, catalyzing the reactions that interconvert CO and CO2 with H2 and H2O:

CO + H2O <====> CO2 + H2 + heat

So while some CO2 reacts directly with H2 to make methanol, the rest gets converted to CO which also reacts readily with H2 to make methanol. The trick, however, will be to ensure that none of the product methanol made from fossil feedstocks in your refinery, ends up being burned at its end of life. You’d need to keep the fossil methanol only for applications which remain unburned. Certain plastics use methanol as a monomer/reagent and fit that bill if we landfill them at end of life, after maximal recycling, rather than burning them.

What About Natural Gas?

Natural gas processing is much simpler than petroleum processing, and the vast majority of the gas is methane. Fossil methane is nearly worthless for anything other than two things: its heat energy content, which is useless post decarbonization due to the cost of CCS, and making syngas- to make fuels which themselves would be useless post decarbonization.

What does that mean? The fossil methane business is dead post decarbonization. We simply won’t produce much gas any more. We might store some for emergency power generation, and make a bit of it into hydrogen and valuable carbon products by pyrolysis, but that’s about it.

Ethane and propane are also found in natural gas and are more useful to make ethylene and propylene and hydrogen. But without a use for the methane, separating these gases out and re-injecting the methane without leaking any is going to look pretty unappealing. My feeling is that we’ll meet most of our ethylene and propylene needs by naphtha cracking in a decarbonized future instead.

So if you’re in the gas industry, as an employee or investor, best to bail now. No, hydrogen won’t rescue you either. You’re going out of business. It’ll take a long while though- longer than it really should, if we were truly serious about decarbonization.

What About Coal?

We do make some materials from coal tar, but none of them can’t be made by other means. And without a need for coke- which we can’t use post decarbonization for anything- there’s no reason to make coal tar. I suppose you could drive off the coal tar and just bury the coke again, but where’s the fun in that? Doubt it will make sense, or money. So we can also bid coal a fond good riddance, at long last.

What Will All This Cost?

Don’t kid yourself: petrochemicals refining will be a whole lot more difficult post decarbonization. That means the processing will cost more. And the scale of petroleum refining will drop, and new investments will be needed. We’re talking about a great deal fewer refineries, purpose built from scratch or almost totally re-built from existing. Huge amounts of money will be needed.

However, demand for petroleum will plummet. Distillates demand is already being affected by electric vehicles- more the 2 and 3 wheeled variety than EV cars and trucks, but they’re coming too. When demand drops to 15-25% of current, only low cost producers will remain in the market. That will drop costs of raw material, because its major market is going bye-bye.

So: petrochemicals and plastics will be more expensive to make, from cheaper feedstocks. Will that mean cheaper, or more expensive stuff? My bet is that it’s more expensive on the whole. And that’s good- expensive means we’ll be motivated to conserve and recycle them better.

Will This Really Happen?

We’d better hope it does.

A growing economy is nice and all, but we need a stable climate. And we won’t ever have one if we keep burning fossils. And while we can keep making materials and chemicals from biomass that the earth deoxygenated for us over millions of years, we need to do that without the burning. We know how. Not a single new invention would be needed- and there would be LOTS of them if we decided to go that way which will help out, a lot. Will we be wise enough to actually follow through on it?

For my kids’ sake, and theirs, I certainly hope so.

Don’t let anybody tell you that we have to do without the chemicals and materials we make from petroleum today. They’re selling you a bill of goods, likely with the intent to make you feel good about burning fossils for longer- or they’re selling you some other ideological point of view. Don’t worry- if we choose to make the economics work via carbon taxes, or to force the emissions out of the system via regulation, we chemical engineers have got your back. We’ll adapt. We have the technology to do it. But without the economic drivers to make it pay, the investments required will not be made, and it simply will not happen.

Disclaimer: this article was written by a human, and humans are known to make mistakes. If I’ve stuffed something up, and you can show me that I’ve done so via good references, I’ll correct my work here with gratitude. I care more about getting the issue right than about being right personally.

If however you don’t like what I’ve written because I’ve taken a dump on your precious idea- F-T running on CO2 and water and electricity for instance- then feel free to contact my employer, Spitfire Research Inc., who will be very happy to tell you to piss off and write your own article.

More Reading

…or watching, in this case- I talk about these ideas with david borlace on his brilliant YouTube channel:

https://www.linkedin.com/posts/paul-martin-195763b_how-can-we-stop-burning-fossil-fuels-if-we-activity-7134627693945393152-QL94/?utm_source=share&utm_medium=member_desktop

Why e-fuels, and their epitome, e-methane, are dumbass:

https://www.linkedin.com/pulse/e-methane-exergy-destroyer-steroids-paul-martin-ynhee

How to make high value products from methane:

https://www.linkedin.com/pulse/hydrogen-methane-pyrolysis-paul-martin-vacnc

…and everything else:

https://www.linkedin.com/pulse/links-all-my-articles-paul-martin-6gxxc

The Primary Energy Fallacy

The Primary Energy Fallacy- or, Committest Thou NOT the 2nd Sin of Thermodynamics!

TL&DR Summary:  if anybody starts talking to you about “primary energy” in a discussion about decarbonization, please punch them in the mouth.  Energy is like currency- there’s an exchange rate between heat (chemical energy) and work (electricity)- they are not  worth the same.  We need to replace useful energy- energy services- not rejected energy arising from heat to work conversions.  Decarbonization is therefore ½ to 1/3 as difficult as these cretins would have you believe.

Source:  https://www.energyinst.org/statistical-review  Primary energy figures, worldwide, 2023

We’ve all seen graphs like this before, from people claiming that the world’s “primary energy” almost entirely (per this one, 84% in 2023) comes from burning fossils as fuels.  And we see these graphs barely changing with respect to time too.  The likes of Canadian professor Vaclav Smil have, in past, been popular proponents of the argument that a transition away from burning fossils as a source of energy is basically next to impossible, or so impractical that it simply won’t happen in less than 100 years, because of primary energy use and our seemingly insatiable demand for oil and gas- not so much coal any more, but hey, they still burn a lot in China…

These people are wrong.  Dead wrong.  Sometimes they even know they’re wrong, but often it’s a result of a bad education in physics.

Energy is like money.  While we like some units better than others in relation to some kinds of energy, ultimately all energy of all kinds is quantified in units like joules, kilowatt-hours, or British Thermal Units (BTUs).  But like money, knowing that I have 100 dollars is not sufficient to know how much value I have in my hand.  We need more information:  in the case of currency, we need to know if these are American dollars or Jamaican dollars for instance.  Both are units of money measured in dollars, but they are not worth the same.

With energy, we’re missing a conversion factor too.  100 joules of heat in a room at 24 C is exactly the same amount of energy as 100 joules of electricity.  But whereas that 100 J of heat at just above room temperature isn’t just worthless, it’s actually an energetic liability if we need the room cooler than that, the 100 J of electricity can be nearly perfectly converted into mechanical energy or perfectly converted into heat at just about any temperature we wish. 

Exergy- and no, that’s NOT a Typo!

To a thermodynamicist, the term “exergy” has a more complex definition, but to a layperson or the average engineer, exergy is simply the potential of a unit of energy to do thermodynamic work, i.e. to be converted into mechanical energy.  100 J of electricity is pure exergy.  100 J of room temperature heat has an exergy value of basically zero.

The exergy value of heat, or proxies for heat such as fuels, varies in accordance with the 2nd Law of Thermodynamics.  Under the 2nd Law, heat engines that convert heat energy into thermodynamic work, have an ultimate efficiency of conversion which is related to the temperature of the “hot reservoir” (the source of heat) and the “cold reservoir” (the place the heat is ultimately being rejected to).  You can think of this as basically a waterfall.  Heat is flowing from the hot place to the cold place, which is the only direction it flows spontaneously.  And we’re running a device on the difference in temperature- a waterwheel of sorts, harnessing some of the flow of heat in its natural flow direction. 

The efficiency reaches a limit set by the Carnot efficiency, which is the ratio of the available temperature difference to the temperature of the cold reservoir, in absolute temperature units (degrees Kelvin, i.e. relative to absolute zero at 0 K).

Some devices for converting chemical energy to work aren’t heat engines per se.  A fuelcell, for instance, converts chemical potential energy into electrical energy without any moving parts.  No mechanical energy is involved.  However, all such devices have their own set of thermodynamic and other practical limits which drop their efficiency below 100%.  The most efficient fuelcell is at present about as efficient as the most efficient full scale heat engine, a combined cycle (gas turbine + steam turbine) natural gas powerplant.  Both convert about 60% of the lower heating value of their feed fuel, to mechanical energy.  And unless the fuel is pure carbon, the fact that we’ve used the lower heating value of the fuel, basically means that we’re throwing away the difference between the lower (net) and higher (gross) heating value of the fuel, which corresponds to the heat required to condense any water vapour produced by combustion and to cool that water down to room temperature.  That energy is not available to the heat engine to use, but if we were running the reverse reaction- making hydrogen as a fuel out of liquid water by electrolysis, for instance- we’d have to put that energy IN to satisfy the 1st law of thermodynamics- the conservation of energy.

We’ve gotten increasingly good at converting heat energy into work. 

And we will indeed need to make some heat into work in a decarbonized future.  We’ll still have geothermal power plants, and nuclear power plants, which work this way.  But today, because we make ~84% of our “primary energy” from chemical energy in the form of fossil fuels, we convert an awful lot of heat to work.  And, per the 2nd law, we do so very inefficiently.  Most of that energy isn’t fed to 60% LHV efficient combined cycle power plants.  Much of it is fed instead to much lower efficiency engines such as those in the average car or truck, with perhaps a 25% efficiency of converting chemical energy into shaft work.  The remaining 75% is just wasted.

That’s the very large, ugly, light gray coloured box in this Lawerence Livermore National Laboratories Sankey diagram of US energy flows, labeled “rejected energy”.  And most of that light gray box is going away in a decarbonized future.  We simply do not need to replace that rejected energy. 

Why not?  Because in a decarbonized future, we’ll be starting with electricity- which is nearly pure exergy.  And if we’re smart, we’ll use that electricity in high efficiency processes to produce the “energy services” (the dark gray box) that we need.

The most obvious of these is that we will no longer be burning fuels to convert a small fraction of that fuel energy into electricity.  But the near elimination of rejected energy doesn’t end there, not by a long shot!

Electrifying Transport- Getting Rid of Rejected Energy

The easiest case in point is the electrification of transport.  Most transport today uses fueled internal combustion engines, and most of these engines are very inefficient, wasting most of the chemical potential energy they are fed.

Battery electric vehicles, in contrast, are very much more efficient.  Lithium ion batteries, including their charging circuitry and all their internal losses, are as much as 90% efficient in vehicular applications.  And electric motors and the inverters to drive them are also high 90% each.  The result is that very few kWh of electricity fed to a battery, end up wasted.  Most of the fed electrical energy goes into moving the vehicle forward against rolling and aerodynamic resistance.  Even better, a good fraction of the energy normally wasted in an engine vehicle every time you need to slow it down by applying the brakes, can simply be converted back to electricity and stored in the battery again with high efficiency.  This is referred to as “regenerative braking”, and it results in an approximately 15% improvement in range while also nearly eliminating the wear on mechanical brakes.

While we won’t soon eliminate fuels from transoceanic shipping and aviation, basically all land transport is going electric.  The result is that most of every barrel of petroleum that we use today- 75-85% of which we generally burn for one purpose or another- will no longer be wasted in this profligate way.  We’ll be able to conserve that precious, finite fossil resource for its highest value use- to make chemicals and materials.  And no, there is no imperative whatsoever to burn anything in that process.

https://www.linkedin.com/pulse/refinery-future-thought-experiment-paul-martin-4pfoc

What will we use for aviation and shipping, and for remote and rural transport?  Biofuels- or, in the meantime, fossil fuels.  These applications will only shift as a result of durable carbon taxes and emission bans.  Over the very, very long term, perhaps electrification will handle shipping and aviation.  The former, requires batteries to drop in cost by an order of magnitude, so that cycling them only every 20 days or so will make economic sense relative to burning a fuel- sodium ion may yet do that for us.  The latter, will require energy density in batteries to improve by at least half an order of magnitude.  That requires a new type of battery-perhaps metal-air.  Neither are impossible, but both are at least a decade or two off.  There is more than enough biofuels potential to handle both in the meantime, if we feel that is a good use of our treasure.  In the meantime however, we should focus on the easy to decarbonize sectors- and that includes almost all of land transport.  EVs there are a no brainer.

Heat Pumps:  The 2nd Law Standing on its Head

The cool thing about thermodynamics is that it is often reversible.  Heat pumps are an example.  Where we lose in converting heat to work, we gain in using work to pump heat.

There’s nothing mysterious about a heat pump.  The 2nd Law says that heat flows spontaneously only from hot to cold, and we know that to be true because of the kinetic molecular theory.  Heat is, after all, vibrating, translating and rotating molecules, bashing into one another.  That was the piece of the puzzle that people like Count Rumford and Carnot were missing when they thought of heat.

However, thermodynamics also makes it clear that we can pump heat from a cold place to a hot place by expending thermodynamic work.  The example is your refrigerator or air conditioner, where heat is absorbed by an evaporating liquid refrigerant, which is then compressed by a mechanical compressor and condensed again, rejecting heat to air pushed by a fan.  Heat flows out of your beer into your kitchen, or out of your house to the outdoors.  Nothing magic about it.  The maximum amount of heat you can pump with a unit of mechanical energy is similarly set by the temperature difference between the hot place and the cold place. 

A heat pump can be used as a heating appliance, taking heat out of ambient air, soil or groundwater, or better still, from something we want to cool down, and transferring it to something we want to heat up.  In a typical heat pump used to heat a home, if you feed 1 joule or kWh of electrical energy to the compressor, you can move on average around three joules or kWh of heat from the cold place to the hot place.  That includes the 1 joule or kWh of electricity you fed, which is itself converted into heat which flows into your home.  The ratio of heat energy out to work energy input is referred to as a coefficient of performance, and in this instance would be 3J/1J or 3.

Heat pumps can use closed loop refrigerants like the example of your refrigerator, or in process applications, a process vapour can be compressed to a higher pressure and then condensed again to transfer heat.  Doing so is called “mechanical vapour recompression” (MVR), and the process vapour- the vapour coming off the top of a distillation column for instance- becomes its own “refrigerant”, transferring heat by condensation in the reboiler.  MVR schemes can have very high coefficients of performance indeed- sometimes in excess of ten.  It all depends on the temperature difference, and also on the maximum temperature which must be low enough for both the working fluid and the equipment being used. 

Conventional wisdom is that heat below about 200 C can be provided to industrial applications by heat pumping schemes with potentially excellent coefficients of performance. Fortunately, somewhere between 40 and 60% of industrial heat joules are used below 200 C.  Above about 200 C, materials and compressor problems make the job harder, but development is ongoing and this limit is likely to soon be exceeded.

Above 200 C, the worst we can do is to basically convert electricity to heat with nearly 100% efficiency.  We can make heat with resistance heaters to about 1000 C, and with microwaves, induction, plasma and electric arcs above that. 

The notion that electric heating is difficult is more one of a lack of familiarity than one of technical difficulty.  In a past where we used ¼ cent per kWh natural gas to make our electricity, it made no sense to use electricity to make heat except where convenience and cleanliness and control were king.  Burning fuels was just cheaper in operating cost terms.  And it was so much cheaper that it was worth a lot of bother coping with hot flue gas coming out of a high temperature furnace.  Heat recovery steam generators, steam production etc. were a result of the need to not waste so much heat.  In a future where we heat the things we want to heat directly with electricity, rather than indirectly using hot flue gas, most of this messy, maintenance intensive, capital-consuming heat recovery stuff simply goes away along with the toxic emissions of combustion flue gas.

Electric heating isn’t difficult.  It just requires us to get the 800,000 year habit of “need heat- what can I burn?” out of our heads. 

There are precious few applications which need fire rather than just heat, and those few that remain, can be satisfied with biofuels. 

And no, there’s no imperative whatsoever to convert electricity into fuels like hydrogen in order to provide heat.  That’s a sin against the 2nd law.  We’ll need to be very rich and very desperate to do that.  All e-fuels, including the simplest one (hydrogen), are exergy destroyers.  And destroying exergy has is working in the wrong direction, just because we’re comfortable with it.  That’s nonsense, and we must get over it as quickly as we can.

https://www.linkedin.com/pulse/breakthrough-electrolyzer-efficiency-paul-martin

Committest Thou Not the 2nd Sin of Thermodynamics!

Now that Father Paul has preached to you, thou shalt not confuse a joule of work with a joule of heat ever again.  Go forth and sin no more against the 2nd Law!  And remember- we need only replace useful energy services.  All that heat wasted by your car’s radiator is going bye-bye for good.  And for good, I mean for the good of the atmosphere and, ultimately, for the good of your wallet.

Disclaimer:  a human wrote this, and humans are known to make mistakes from time to time.  If you find an error, bring it to my attention with good references and I’ll fix it.

If however you simply don’t like what I’m saying because I’ve taken a dump on your pet idea, feel free to complain to Spitfire Research Inc., my employer, who will be happy to tell you to piss off and write your own article.

The Case Against Hydrogen Trucks

This article is a companion to my recent article about why I think battery electric trucks are the future of freight:

Electric Trucks- the Future of Freight

TL&DR: hydrogen trucks are largely just a retreat position for people who previously thought hydrogen cars were going to be a thing. They won’t be. There is no realistic value proposition for hydrogen trucks, whether powered by fuelcells or, even dumber, by IC engines running on hydrogen.

How We Got Here

We all know, or should know, that the hydrogen fuelcell car is deader than a doornail.

Comparing the Mirai to the Model 3- Tesla Wins

Whereas it looked like the only game in town for cars without a local toxic tailpipe back in the 1990s, the battery EV has come along, sold millions, and driven a nail into the fuelcell EV (FCEV)’s tanks. Fortunately there was just a loud hiss, not an explosion, but the result was the same.

Why Are We Still Talking About Hydrogen Trucks?

Those who were pushing hydrogen cars, weren’t going to just pack up and go home. They retreated into the use case of trucks, arguing the following:

1) Batteries are heavy, and since trucks carry loads which are limited in weight by the total gross weight of the vehicle plus its load, and because hydrogen has better energy density per unit mass, a truck of adequate range to be practical for freight haulers needs hydrogen if it is to be decarbonized.

2) Batteries are intrinsically more efficient than if we were to use electricity to make hydrogen for use as a transport fuel (by roughly a factor of THREE). But if we can make hydrogen cheaply enough, the added effectiveness of faster refueling and longer range will make the inefficiency irrelevant.

3) Hydrogen will be cheap because electricity will be cheap, and hydrogen will be needed for all sorts of things old and new so scale will make hydrogen cheap.

4) The grid can’t handle EVs. But we can put hydrogen in pipes- maybe even in pipes currently used for natural gas. So hydrogen is more practical to distribute than electricity. And hydrogen offers the advantage of energy storage. Storing 3 kWh worth of hydrogen is cheaper than storing 1 kWh worth of electricity in a battery.

This stuff finds its way into studies, largely done by people who benefit from the hydrogen attempt whether it succeeds or fails. And sometimes, by academics who are jumping on the square-wheeled bandwagon- and who haven’t read papers from the likes of Ulf Bossel and Reuel Shinnar from the 1990s, when all the fundamental issues for why there wasn’t going to be a hydrogen economy, were already spelled out, in gory thermodynamic detail.

But hey, let’s take these notions apart, and see if they are valid. Just because we’ve got nothing better to do.

Hydrogen Light, Batteries Heavy, Therefore Hydrogen

As my article about electric trucks points out, per the North American Centre for Freight Efficiency, 75% of freight loads aren’t limited by maximum gross vehicle weight, but by trailer volume or floor area.

Hydrogen’s energy density per unit mass- 33.3 kWh of LHV per kg- is awesome- especially if you forget about the mass of its containers. Those containers are pressure vessels typically designed to withstand 350 bar for trucks, rather than 700 bar for cars. And those tanks, even made cleverly using aluminum bottles over-wrapped with kevlar and carbon fibre, are heavy because they must safely contain an enormous amount of mechanical potential energy. They also have a limited cycle life, just like a battery- you can only safely fill and empty them so many times before they become unsafe, whereas a battery just loses capacity the more you cycle it. So is there really a huge savings to be had, switching from small battery plus fuelcell and hydrogen tanks, to big battery? Not really. And a little extra weight will affect only 25% of loads anyway- many of which are tanker trucks full of fossil fuels.

On the other hand, hydrogen’s energy density per unit volume is not so awesome. Hydrogen at 350 bar is about 21 kg/m3. If you were to feed a 60% efficient fuelcell with hydrogen, the resulting 20 kWh of electrical energy returned per kg x 21 kg/m3 is about 420 kWh/m3, or about 420 Wh/L. That’s almost exactly the same as the Model 3’s battery pack. Except much worse, because the tanks are cylinders with hemispherical heads- they don’t pack together nicely. And no, we’re not expecting BEV tractors to be substantially larger than the diesels they replace, due to battery volume. Getting rid of the diesel components leaves sufficient room for quite a large pack.

Of course you could increase the energy density of hydrogen to 71 kg/m3 by using liquid hydrogen- at 24 degrees above absolute zero. That would unfortunately cost you about 30% of the energy in your hydrogen (making the efficiency markedly worse), but you’d need to put that in via electricity to run the Claude cycle compressors to make that liquid. That’s a pretty terrible tradeoff. And in tanks the size of a tractor trailer tanker, liquid hydrogen boils off at more than 1% per day- in tiny tanks that you might want to put on a truck, the boil-off would be ridiculous. You’d need to burn that hydrogen any time the truck wasn’t demanding it, as its global warming potential (GWP) is 11.5x that of CO2 on the 100 yr time horizon. It’s not toxic, but its flammability and high GWP mean you can’t just vent it like we did in the bad old days.

There is no hydrogen-derived “new LNG” in the future- here’s why!

And no, there’s no solution to these fundamental problems- no magic graphene absorbent that will make hydrogen denser than it is as a liquid. High pressure hydrogen is chosen because of all the bad options for hydrogen storage for transport applications, it is the least bad!

The reality is that hydrogen as a transport fuel is neither efficient nor effective. Its inefficiency makes it structurally expensive, and its ineffectiveness (arising from its low energy density per unit volume) makes it expensive to store, distribute and dispense.

Fundamentally. For reasons you can’t change with innovation.

Efficiency Doesn’t Matter, Therefore Hydrogen

Hydrogen trucks will take three times as much energy from source as BEV trucks to go the same distance- round numbers. You might get that down to two times with massive improvements in both electrolyzers and fuelcells, but that’s about as good as it will ever get. But hey- three times zero is zero, right? If electricity is cheap enough, why would we care about wasting it?

Well…hydrogen is three times as expensive for energy per mile driven. In an industry which charges its customers a fuel surcharge, that alone should be a deal killer. But it’s way, way more than that by the time you’ve figured in the cost of making hydrogen (the equipment and labour needed to convert electricity and water to hydrogen), distribute it to fueling stations, and dispense it.

Hydrogen Distribution and Dispensing Both Suck

Hydrogen’s low energy density per unit volume means that currently, we don’t move or store much hydrogen at all. 92% of hydrogen moves essentially no distance- it’s made right where, and when, it is consumed. Why is that? Because it’s cheaper to move whatever we’re going to make the hydrogen from, to where hydrogen is needed. There are some hydrogen pipelines, but they exist more for outage prevention, to connect a bunch of hydrogen reformers to a bunch of refineries and chemical plants within a short distance from one another.

And no, it ain’t so simple to just switch which gas we put in the natural gas transmission network. That’s just not on, despite how hard the people who own that network, are selling you on the idea (because the alternative is to admit they’re going out of business).

Hydrogen to Replace Natural Gas? Forget About It!

What about tube trailers? Oh yeah, just forget those. A full Class 8 DOT certified tube trailer contains 380 kg of hydrogen.

380 kg of hydrogen i a whole truckload- if you have a scavenger compressor that can go down to atmospheric pressure that is!

A full Class 8 DOT certified gasoline or diesel tanker contains 11,000 gallons of these fuels- and to a 1st approximation, 1 kg of H2 is about the same LHV as 1 gallon of gasoline or diesel. That means we’re looking at around 30 tube trailers for hydrogen for every one tanker of diesel we delivery today. Yes, there are people working on composite tube trailers which would run at higher pressures. Sadly, they’ve been leaking and catching fire. But one day, they might drop that to ten trailers instead of thirty. Still deader than doornail as a distribution method!

Everybody has a model in their head of hydrogen refueling as being as simple as plugging a hose into the truck and turning a valve. That’s of course far simpler than reality. Reality is hiding behind the curtain, and there’s a lot of complexity there. First, you need to get the gas there, and as discussed above, that’s hard and expensive, because it implies either building new, bespoke hydrogen pipelines from some large scale centralized hydrogen production facility- in North Africa, say- and then distributing that hydrogen to every refueling station. Or else you’re talking about distributing three times as much electricity to each refueling station and then running comparatively tiny electrolyzers at each one. The problem with tiny electrolyzers is that they are fundamentally incapable of ever making cheap hydrogen. And of course they make the grid problem, three times as hard as if we just used BEVs instead!

Breakthrough in Electrolyzer Efficiency!

Even once it’s on site, you need to compress it to 350 bar. And because the tanks on the truck are composite tanks, they can’t handle much heat. So you need to chill the hydrogen so that as it expands and heats up (a weird property that it shares with helium), it doesn’t cook the tank it’s being fed into. Want to do that fast? You need a really big chiller. And it needs to be sitting there on standby in case a truck rolls up and needs refueling.

I’ve been involved in designing hydrogen storage and dispensing systems, and I can tell you that anybody who thinks that the capital cost for hydrogen refueling is going to be lower than that for megawatt chargers, has another thing coming.

Faster Refueling- Really?

The reality is that hydrogen refueling also gets harder the larger the vehicle you intend to refuel. So whereas you might refill a Tesla Semi from 20% to 80% battery state of charge (SOC) in ~30 minutes using a megawatt scale charger, the best you’re going to do with a hydrogen truck in practical terms is around 20 minutes on the pump. Not five. And no, it will absolutely not be faster if you use liquid hydrogen, either.

Hmm: (much) more than three times as much energy cost, in return for saving 20 minutes of refueling. Yes, I know that 20 minutes of truck and driver productivity are worth money- but are they worth that much money?

But You Can Store Hydrogen!

Yeah, and the battery on the truck is what, chopped liver?

The notion that hydrogen storage onsite at refueling stations, plus intermittent operation of electrolyzers on site, will save demand charges that would drive up the cost per kWh of BEV charging is also popular. But the notion that it’s worth throwing away 2 out of every 3 kWh you feed such a system, just to store energy, is very questionable indeed. Worst case, megawatt chargers would need to be paired with larger grid storage batteries on site, which would do the same thing as hydrogen would, but at 90% instead of 33% efficiency! And of course any time you operate an expensive asset like an electrolyzer intermittently, its cost per kg of product goes up- way up.

Scale Will Make All Problems Go Away!

No, folks, it won’t.

First, most of the “hydrogen economy” rubbish is just as dumb as hydrogen for transport. So while I do see a great need for green hydrogen to replace the black stuff that’s keeping us alive and fed via ammonia production etc., and a few new uses to decarbonize iron production (also an existing use of hydrogen that just needs expanding),

I don’t see a hydrogen economy coming.

Ever.

Transport fuel use of hydrogen is only one of several dumb use cases being proposed, but yeah, it’s a real stinker.

Yes, scale will help make electrolyzers and fuelcells cheaper. No, electrolyzers aren’t going to get as cheap as some are dreaming, because they don’t understand economy of scale and Wright’s Law properly- and I do, because I spent decades as a specialist in scaling up chemical processes and equipment.

Scaling Example #2: Water Electrolysis

And while scale will help with fuelcells just like it will help with electrolyzer stacks, not their balance of plant, without the scale of cars and light trucks, there simply won’t be sufficient doublings available to make fuelcells cheap enough if we use them only in class 8 trucks and heavy equipment.

And no, we won’t be using them in aircraft, either. Talk to Bernard van Dijk about that- he’s one of my co-founders of the Hydrogen Science Coalition, and he’s forgotten more about aircraft than I’ll ever know.

Hydrogen for Aircraft- HSC Explainer Video

Nor for ships.

Nor for stationary power.

No, scale won’t come to the rescue here. Hydrogen as a transport fuel is just broken. It’s a cart with square wheels.

Image credit: Michael Sura

The Bottom Line

Battery electric trucks aren’t a pin for pin replacement for diesels. And thank goodness! They drop GHG and toxic emissions, are easier to drive (no 18 gear transmissions), quieter, and will have less maintenance (particularly for brakes). But that will leave some transport truck use cases, unserved. Can hydrogen fill those, at least?

Let’s consider remote and rural transport. The example I like to use is ice road trucks which resupply First Nations communities in northern Canada. They’re not going electric, for sure. Are those going hydrogen?

Forget about it. Fuel logistics kills the idea deader than a doornail.

Remember those tube trailers?

Nope. Those will either need to keep running on fossil diesel, or if we’re worried about the 3/4 of eff all GHG emissions that are produced by that tiny fraction of tonne-miles of freight, we can make them use biodiesel instead. That would work, and would cost only modestly more than fossils. Hydrogen wouldn’t work, period.

What about Hydrogen Engines?

Hydrogen engines make all this stuff worse. Fuelcells are selected, despite extra cost, because they are more efficient and hence lessen hydrogen’s problems of cost and energy density per unit volume. Engines don’t help, and hydrogen engines will generate both particulate emissions from combustion of lubricant oils in the engine, and NOx- the inevitable result of burning anything in air.

This excellent video talks about Toyota’s hydrogen car engine, and how ridiculous it is, in unambiguous and clear terms, with all calculations provided.

The Unbearable Lightness of Hydrogen

What About E-Fuels?

In a recent debate, where I basically cleaned the floor with the arguments of the executive director of the Canadian Hydrogen and Fuelcell Alliance, the great hope apparently isn’t for hydrogen, but for hydrogen-derived fuels- so called e-fuels such as ammonia or methanol. These are all attempts to a) keep using engines b) make hydrogen more effective, but also c) make hydrogen even less efficient. And I freely admit, for aircraft and ships, we might be so desperate, and sufficiently rich, to reach for some e-fuels- or, at least, to use green hydrogen to run the hydrogenolysis reactions necessary to make drop-in fuels out of biomass. We’ll need to be rich though. And for land transport, where BEVs are a real alternative that is cheaper in energy cost than fossils already, that just makes no sense to me at all. E-fuels for land transport are really the sport of Porsche owners- because only Porsche owners will be able to afford them.

Ammonia as a transport fuel is horrifying. I spent decades designing and building systems which handle and store chemicals, sometimes chemicals so hazardous that they make ammonia look like mother’s milk. But ammonia isn’t just a poison gas, with a concentration immediately dangerous to life and health (IDLH) of only 300 ppm- it’s also extremely corrosive to eyes, the linings of the mouth, nose and throat, ears etc. etc. One tanker truck of ammonia in 1970s Houston was the cause of Houston’s most serious chemical incident in its history. One tanker, scores of deaths and grievous injuries. Anybody recommending ammonia as a vehicle fuel had better be ready to put on their level A pressurized SCBA chemical protection suit and go in there to repair a leak, or they’d better shut up about it right quick. I know I’m not- I’ve been in one of those suits. Truck transport with ammonia would be bad, but ammonia to fuel ships at sea is, to me, next level idiocy.

Ammonia? Pneumonia!

I don’t think we’ll even need biofuels here. It’s a certainty to me that virtually every use case for land vehicles is going electric. For the better.

Disclaimer: I’m human, and I make mistakes even when I don’t write my articles with a glass of home-made scrumpy in hand. Point out where I’ve gone wrong, with references, and I’ll gladly correct my work.

If however you just don’t like what I’ve written because I’ve sh*t on your company’s precious idea, feel free to contact my employer, Spitfire Research Inc. They’ll be more than happy to tell you to piss off and write your own article. Or, just block me- that’ll be your loss.

Why Direct Air Capture (DAC) Sucks- and Not in a Good Way!

UPDATED January 15, 2026 and August 8, 2023

You’ve likely heard the sales pitch before:

  • there will be fossil CO2 emissions we simply cannot eliminate
  • even once we do reach actual or near-zero fossil CO2 emissions, we’ll need to “draw down” CO2 from the atmosphere to avoid the need to cope with global warming long-term
  • renewable energy will be super-abundant and super-cheap one day, so designs predicated on the notion of wasting vast quantities of it aren’t as stupid as they might seem on their face
  • yeah, I know, that last point wasn’t convincing, and it really is stupid right now, but we need to work on it so it’s ready when we need it

What am I talking about? Direct air capture- the act of using active mechanical/chemical equipment and vast quantities of renewable energy, in a totally pointless fight against entropy, to try to suck CO2 out of the atmosphere for either durable burial or “use”.

You’ve all seen the images- CGIs of vast rows of giant vacuum cleaners, fixing the problems of history. Hurray! The deus ex machina solution to climate change has arrived. Go on sinning, folks- keep burning fossils with wanton abandon! Because some day, some bright propellor-heads will find a way to just suck our sins back out of the atmosphere!

Do you see the danger of that fantasy? I certainly do. And as a chemical engineer, I realize how preposterous it is to even think about moving minimum 1600 tonnes of air around mechanically to have the hope of removing 1 tonne of CO2 from it at 416 ppm.

DAC: The Idiot Cousin of Carbon Capture and Storage (CCS)

Let’s be crystal clear here: you’ve likely heard people say things like “CCS doesn’t work”. They’re wrong. CCS works just fine in terms of its real objectives, which are captured in this, the most accurate and concise reference in relation to CCS that I’ve yet come across:

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=7854498476142677140&li_theme=light

(Warming- language might make a sailor blush!)

Yes CCS works just fine, in terms of extending social license for fossil fuel use, and as a marketing tool for the fossil fuel industry, and in terms of regulatory capture etc.

Update: don’t take my word for it- take the fossil industry’s word for it!

“We believe that our direct capture technology is going to be the technology that helps to preserve our industry over time,” Occidental CEO Vicki Hollub told an audience at CERAWeek, an oil and gas conference, earlier this month. “This gives our industry a licence to continue to operate for the 60, 70, 80 years that I think it’s going to be very much needed.”

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=9117772129042268467&li_theme=light

Even if you are to look at it technically, CCS works just fine- you just can’t afford it, even under nearly ideal conditions.

This video does a good job of taking the mickey out of the whole “clean coal” thing, which was predicated on CCS “working”. It’s worth a watch, and is a good laugh- though not quite as good as the Juice Media one above;

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=8362811377031999537&li_theme=light

How do I know that CCS works “just fine”? Because the “capture” part is done routinely by the fossil fuel industry day in, day out, as a normal part of business. Every hydrogen generation unit on earth does it. Every liquefied natural gas (LNG) plant does it. Most of the fossil gas processing plants do it too, removing some CO2 to get the gas up to pipeline spec in terms of energy content. And a great many chemical plants remove CO2 from either feedstocks or product streams, because the gas gets in the way otherwise.

In chemical engineering terms, the capture part is childsplay, because CO2, aside from being bigger and bulkier, also has a “handle” on it that other gases in the atmosphere like N2 and O2, and the methane that makes up most of fossil gas, don’t have. CO2 is an acid gas, and so it chemically reacts with bases. And that reaction can be made reversible, too. So we can use that “handle” to separate it out selectively from mixtures of other gases.

Of course if the atmosphere can be treated as a free or very cheap public sewer, you don’t bother with the “S” part- you simply vent the gas once you’ve collected it. And if that alternative is on the table, there’s no big impetus to put a whole lot of effort and energy into making sure your “CCS” project meets its design objectives- so, sometimes these projects don’t. And often, it’s for reasons other than the “capture” part. Gorgon, for instance, is having trouble with the “storage” part, because the reservoir they want to dump the CO2 into, needs to have water pumped out of it- and the receiving reservoir for that water is clogging up with sand. Or something like that- anyway. Ask a geologist.

The Basics of CCS

Any time you try to take a dilute mixture and make it into a concentrated mixture, you’re going in the opposite direction to the one the 2nd law of thermodynamics says that things go spontaneously. The spontaneous direction is for concentrated things to become dilute, hot things to become cold etc. etc. By trying to go in the other direction, you’re locally decreasing entropy, by pushing something up a concentration gradient. No problem, says the 2nd law- you simply have to pay your tithe in terms of energy, and ensure that the entropy of the entire universe increases in net terms when you’re done. The bigger the concentration gradient, the greater the entropic “tithe”- the more energy you need to use to make it happen.

It stands to reason. Imagine you’re given 100 golf balls- all white, except one. You can look at each ball, but only one at a time, and you can’t stop looking when you’ve found the orange one- once you’re in, you’re committed to looking at all 100. Wow, what a pain! But you could do it, if for some reason you really wanted that one orange ball.

Now let’s say that instead of 100, it was 10,000 balls, and still only o

ne orange one…

You can see that the lower the concentration, the more of a pain in the @ss this is going to be. That’s the 2nd law.

In terms of gas mixtures, the thing that really matters is the partial pressure. The partial pressure is the product of the volumetric concentration of the gas, and the total pressure.

Take, for instance, the syngas stream coming out of a steam methane reformer. The gas mixture is about 15-20 volume % CO2, at a pressure of about 25 bar(g). The partial pressure of CO2 is therefore about 0.15*26 =~ 3.8 bar.

Let’s compare that to the atmosphere. It’s 416 ppm CO2 at a total pressure of 1 bar(a). That’s a partial pressure of 0.000416 bar.

Hmm- looks like getting the CO2 out of the 1st one is going to be quite a bit easier than the 2nd one, eh? Yup. Way, way easier. You need to process 3.8/0.000416 or around 9100 times as much gas volume in the case of the atmosphe

re, to obtain a tonne of CO2- assuming that you captured it all.

But in fact the partial pressure we’re most concerned about is the partial pressure at the discharge, not the inlet. So doing 90% capture (removing all but 10% of the CO2 in the incoming gas stream) takes considerably more energy than doing 50% capture- not just because you have to process more gas, but you have to do a better job of “sifting” it.

There are other complexities, but to a first approximation, the following are borne out when you look at CCS projects in the world:

1) The stuff you’re removing the CO2 from, has to be worth money, and the CO2 must be a problem, otherwise you won’t bother removing it.

2) The partial pressure of the CO2 has to be pretty high to make it worth the bother of removing it.

3) That means either the concentration of CO2, the total pressure, or preferably both, need to be high, or you won’t bother doing it

4) That means process streams, rather than waste gas streams, are the main thing you’re going to remove CO2 from, because they’re easy, i.e. they require less expensive energy

5) Combustion equipment usually doesn’t operate at high pressure, and is usually carried out using air (which is 79% useless nitrogen), resulting in low CO2 partial pressures- so post-combustion CO2 capture is unusual (though it is done- when the desired product is CO2, for instance for carbonating drinks)

When you look at “CCS” projects therefore, what you usually find are projects like Sleipner and Gorgon, where there’s a lot of CO2 in an otherwise valuable fossil gas stream coming up from the ground under pressure, which must have its CO2 removed before it can be monetized, and where the CO2 is being buried rather than vented for regulatory reasons (i.e. venting isn’t allowed by the local government).

Rarer are projects like Quest, the blackish-blue bruise-coloured hydrogen project in Alberta which is burying 1 million tonnes of CO2 per year which must be removed from the hydrogen, but which ordinarily would be vented- except instead, the Canadian public through their tax dollars are paying to bury it instead.

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=9206211868763931922&li_theme=light

What you rarely see are post-combustion CCS projects, where CO2 produced from energy production such as burning fossil gas or coal is captured and then buried. Why not? Low partial pressure, meaning high energy cost, and extra cost due to loss/destruction of the bases (amines) used in the carbon capture equipment. In those cases where post-combustion CO2 capture is carried out, invariably the proponents seek to monetize the CO2 by doing enhanced oil recovery. And that, folks, really isn’t CCS- it’s a way to “dryclean” an existing oil reservoir to recover more oil, and only a fraction of the CO2 injected remains buried. EOR is an attempt by the fossil fuel industry to be paid twice for its CO2- and while post combustion CCS is better than mining naturally occurring CO2 for this purpose, the even better choice is to stop mining fossils for the purpose of burning them.

The Thermodynamics of Gas Separation Technologies

It is easy enough to calculate the reversible (equilibrium) amount of energy that it takes to return a mixture of two things, to two containers each with pure substances in them. This is the absolute minimum amount of energy possible to accomplish that separation task, within the limits of thermodynamics. It is also the amount of energy liberated when two pure substances are mixed. Yes, there really is energy liberated when, for instance, a river of fresh water, is diluted into the ocean- and there are even some largely foolhardy schemes intended to use some of that energy to produce electricity.

However, no real separation process operates at equilibrium. All real processes must operate at some distance away from equilibrium so that the rate of separation is substantial, using equipment of a size that isn’t infinite.

Real gas separation processes, executed using real, well developed, routine chemical engineering processes which have been optimized over periods of up to a century, don’t actually operate anywhere near their equilibrium minimum reversible energy input requirement. They use a multiple of that energy input- with that multiple, as should be expected, growing larger and larger as the amount of dilution increases.

Real gas separation processes, executed using real, well developed, routine chemical engineering processes which have been optimized over periods of up to a century, don’t actually operate anywhere near their equilibrium minimum reversible energy input requirement. They use a multiple of that energy input- with that multiple, as should be expected, growing larger and larger as the amount of dilution increases.

The equipment design becomes an optimization between capital and operating costs. Departing from equilibrium to provide a driving force for mass transfer, reduces the surface area necessary for capture and by so doing, reduces the capital cost of the equipment, but comes at the cost of more energy, i.e. a greater departure from the minimum achieved at equilibrium. With DAC, there’s also energy required to move the enormous amount of air through the apparatus. 1600 tonnes of air must flow through the pressure drop of your equipment to have the potential to capture 1 tonne of CO2 if capture per pass is 100%- 3200 tonnes if capture is reduced to 50%, and 6400 tonnes if capture is 25%. And the more intimate you make the contact between the absorbent and air to drive mass transport and save capital by reducing the necessary contact area, the more energy you use moving air around. Go the other direction- try to use natural air movement (wind) to carry the necessary air through your equipment, and the required area becomes enormous very quickly.

This excellent reference, looks at Sherwood plots of real gas separation technologies, and analogous purification technologies such as the reverse osmosis purification of seawater. And it predicts that unless someone makes an astounding, utterly unexpected and miraculous new discovery (this is not impossible, but certainly highly improbable!), DAC should be expected to operate at around 5% of its reversible thermodynamic minimum energy input. And that is, pretty much, all you need to know to be SURE that DAC is never going to be a reasonable, realistic decarbonization strategy.

(PNAS download link below: Herzog et al, “Energetic and Economic Analysis of Capturing CO2 from Ambient AIr”.

https://lnkd.in/emCXDfha

Here is the Sherwood plot from that reference, showing similar, analogous separation processes and how their efficiency, relative to the ideal reversible minimum energy input, varies with the amount of concentration increase which is required by the separation (i.e. a function of how high the concentration of the target material is in the source mixture, and how concentrated the end resulting material must be to be useful)

You can see, hopefully, that an efficiency of beyond 10% would be an extraordinary, unusual achievement, and that efficiencies of less than 1-5% might in fact be a reasonable assumption.

From that reference, here is the cost of energy alone to remove a tonne of CO2 from ambient air, as a function of eta (n), the efficiency with which the gas separation process achieves the separation relative to the ideal, reversible equilibrium minimum amount of energy required.

Note that this is the cost of energy alone, and doesn’t allow any cost for capital equipment, or even the energy required to move 1600 tonnes of air through that equipment. It also completely ignores CO2 disposal cost, in both capital and operating cost terms.

It should be clear from this work, and by comparison against real CCS costs at Shell Quest, where public data is available, that DAC would require an absolute miracle to ever have CO2 capture costs become low enough to be meaningfully useful as a GHG emission mitigation strategy.

It would take extraordinary evidence to demonstrate that anyone had, in fact, achieved such a miracle.

Forget About CO2 Re-Use

And please, for once and for all, let’s forget about the “use” thing, i.e. CCUS. Let’s be clear about what CO2 is: it’s a waste material. The very thing that makes CO2 (and water) a valuable product of energy producing reactions like combustion, makes it a poor starting material from which to make much of anything useful. What is that thing? Low Gibbs free energy, i.e. low chemical potential energy. Think of fuels as sitting on top of a chemical potential energy cliff. Throw them down the cliff by reacting them with oxygen to make products like CO2 and water, and you liberate chemical energy. But the 1st law of thermodynamics says that you must put back all that energy if you want to start with CO2 and water and use them to make fuels again- and the 2nd law says that each energy conversion is going to come with losses. As it turns out, the losses involved in climbing that particular cliff are very, very steep indeed.

Of course some readers are scratching their heads or perhaps throwing chicken bones at their computer screens right now, yelling that CO2 (and water) is the basic building block of life on earth. And yeah, you’re right. Plant life takes CO2, water and the energy from sh*tloads of visible light photons, collected and stacked up on top of one another in an incredibly complex chemical shuttling process called “photosynthesis”, to produce carbohydrates- the stuff from which plants are made and the stuff (nearly) the entire rest of the ecosystem uses as a source of chemical energy (i.e food).

Nature’s been at this for about a billion years, and has managed some shocking leaps forward in the efficiency of photosynthesis. The energy efficiency, after all that time, is about 2% at best.

Why? Because it’s frigging hard to do. Nature does this because a) the sun is a limitless source of energy b) to nature, time is irrelevant and c) it has no choice.

There are a handful of highly oxygenated chemicals which might be worth making from CO2, water and electricity in the future. The only one of them which is a “fuel” in meaningful terms, is methanol- and right now, all the methanol in the world is made from fossil gas via the manufacture of syngas, without CO2 capture. Fortunately, most of the methanol produced in the world is like almost all the hydrogen- it isn’t wasted as a fuel, but rather is used as a chemical.

Reference Costs

Shell Quest provides a great reference. The article I wrote about Quest, linked above, provides links to the public sources of information about the project. It was done by experts, not dummies- it was designed and executed by Shell and the giant EPC Fluor. Conditions are ideal- high partial pressure CO2 in process syngas is all they go after, capture percentage target is modest (80% of the CO2 in the syngas), and they have an ideal hole in the ground to stuff the resulting CO2 into, only 60-ish km away.

What does it cost? $145 CDN per tonne of CO2 emissions avoided. Shell claims on the project website that they could do the next project “for 30% less”, but that was before COVID/wartime inflation. And in facilities terms, net of the energy (heat and electricity) used to run the CCS equipment, capture is terrible- only 35% of the CO2 in net terms is captured. Figure in the methane emissions and CO2e capture is even worse- by my estimates, only about 21%.

Too expensive. By the time a reasonable payback on capital, realistic costs of energy and some profit are included, the cost of doing this is north of what carbon taxes will be in Canada even in 2030- even assuming we keep electing pro carbon tax governments (and I sincerely hope we do!). Unless carbon tax levels are both high and very certain, nobody is going to do this without additional government “help”. That means taking money collected in taxes on things we want, or should want, i.e. people and businesses making goods and services of real value- and using those funds to pay the likes of Shell to bury its effluent.

So much better to just reduce how much effluent we generate, by buying less of Shell’s products!

Why does DAC Suck?

As you might have concluded from the foregoing, DAC sucks not just because of its obvious use as an insincere strategy to keep us burning fossils for longer based on a false hope- but also because the partial pressure of CO2 in the atmosphere, though higher than we can tolerate in climactic terms, is very low indeed in absolute terms: only 0.000416 bar. That means you’re involved in not only an entropic fight, requiring lots of energy to capture even a little CO2, but you also generally have to move a lot of air around mechanically to make it work out. And there’s a lot of other stuff in air- dust and dirt, water vapour and the like- which can screw up your equipment, depending on how you do it.

As badly as “blackish blue” hydrogen looks, doing that would be much smarter than doing DAC. And capturing the CO2 from calciners making cement from carbonate rocks, would make even more sense- especially if those calciners were electrified using renewable electricity.

The energy use inherent to the thermodynamic foolhardiness of DAC means that DAC is, until we stop burning fossils as a source of energy, basically an energy-destroying Rube Goldberg apparatus to rival something out of an OK Go video:

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=7395990230454582828&li_theme=light

Here’s a hilarious bit of inadvertent accuracy on the part of the National Renewable Energy Laboratory (NREL) in relation to DAC- an image which is missing only the wire connecting the polluting power plant to the useless DAC machine!

As I’ve said many times: over here, on the left hand side of the image (most of the world sadly!) we’re burning fossils to make energy. Over there, on the right hand side of the image, we apparently have vast amounts of renewable energy which we want to waste by running an energy-destroying Rube Goldberg apparatus. The obvious solution is to connect “here” and “there” with a WIRE, and throw away the worthless, energy-sapping molecular middleman!

DAC’s Biggest Players

There are plenty of players trying to suck up the credulous, foolish funding for DAC approaches being offered both privately and through government agencies, but the two main proponents at present are the (regrettably) Canadian company Carbon Engineering, and the Swiss firm Climeworks (whose image I modified for this article). There are also “passive” DAC approaches, such as people trying to grind up silicate rocks so they can “weather” and become carbonate rocks quicker than they would naturally. Those approaches have their own problems, but they’re not the target of this particular missive on my part- you’ll need to wait for a future article for me to take them on. In this one, my sights are set firmly on the big, iconic, CGI-generated vacuum cleaners- my target is the “meme” of DAC.

Carbon Engineering’s approach is to use a two step process. A strong base (potassium hydroxide) is used to capture the CO2 in the big vacuum cleaner thingies, making their DAC equipment quite a bit smaller and more practical than if a weaker base were used- but at the cost of making regeneration of that base, harder and more energy-intensive (thermodynamics sucks, doesn’t it?). Their solution is to use the calcium oxide cycle, generating calcium carbonate as their strong base is recycled. The calcium oxide is regenerated from the calcium carbonate- get this- by burning fossil gas…

Their principal investors, Chevron and Oxy Petroleum, are interested in using DAC to produce CO2 for use in EOR, while also harvesting credulous government money for CCS credits. Wonderful! Michael Barnard has done a marvelous job of bashing this dumb scheme already, so I don’t need to bother doing any more than pointing you to his excellent work. He calls Carbon Engineering “Chevron’s Fig Leaf”, and I cannot disagree.

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=9001131737604206402&li_theme=light

The other guys, ClimeWorks, use a “highly selective filter material”- what this is, is not clear, but it appears to be a base fixed to a solid. The base is then heated to 100 C to drive off the CO2. No, they get no entropic benefit from any magic beans in their “filter”- they’re fighting the same pointless battle that Carbon Engineering and the rest are fighting, just using different tools. But at least ClimeWorks doesn’t burn fossil gas to regenerate their “filter”- they power their units with “100% renewable energy or waste heat”. Their big showcase project is in Iceland, where clean-ish geothermal electricity and heat is used to run their DAC machine. The resulting CO2 is injected into water returning to a volcanic aquifer rich in silicates. Over a period of years, the CO2 in this water “weathers” the silicates, converting them to carbonates.

ClimeWorks seems to have settled on the business model of voluntary carbon credit harvesting. Pay us to capture and bury your CO2, at the low low price of $1,100 USD per tonne!

Wow- imagine the real emissions reductions we could do for way, way less than $600/tonne…Like electric vehicles, where the car costs more, but the total cost of ownership to the vehicle owner- and hence the cost per tonne of CO2 emissions abated- are in fact negative to the vehicle owner…

But hey, I get it. The big vacuum cleaners to the rescue will let some people drive their big, dumb pickup trucks with a little less guilt- even if those DAC units are just proposed and not actually built…

Carbon Negative Technologies Which Work

I can hear the complainers already. “You just sh*t on everything everybody else is doing- what are your solutions?”

I’ve laid out my solutions very clearly. I’ve even mis numbered them, so your solution can be slotted in where you see fit:

https://www.linkedin.com/embeds/publishingEmbed.html?articleId=7419327695933514242&li_theme=light

What are the solutions? Read the $)(*@#$ article! But in summary:

1) Make CO2 emissions cost something- a high and durable price

2) Stop wasting precious, finite fossil resources as fuels. Use them instead to make the 10s of thousands of molecules and materials every bit as essential to modern life as is energy, but which are far, far harder to make starting with biomass much less CO2 and water and electricity! Electrify everything instead. And if you think you can’t electrify it, try harder.

3) We’ll need some liquid fuels in the future, for applications like long distance aviation which simply cannot do without. Don’t make them the lugubrious way using CO2, water and electricity, because that’s nuts. Instead, start with biomass. Yes, the cheapest way is using food biomass, because all of agriculture so far in human history has been optimized around getting plants to put as much energy into the parts we harvest for food as possible. But we can also start with cellulosic materials- wood waste, corn stover, sugarcane bagasse, rice and wheat straw etc. Make those fuels via pyrolysis, produce biochar and return that to the fields and forests the source biomass came from, closing the inorganic nutrients loop and providing a service formerly provided to the ecosystem via wild fire- something humans simply cannot tolerate. Yes, the resulting fuels will cost a fortune, but they’ll be cheaper than e-fuels, and every mile flown by rich people on jets will have the net result of taking carbon OUT of the atmosphere and tying it up for centuries if not millenia in the soils. But don’t expect that to happen voluntarily- you’ll need to force it via regulation or it just will not happen. I like this char approach much better than other bioenergy plus carbon capture and storage schemes (BECCS). Burning wood and doing post-combustion CCS is pretty much a non-starter based on my analysis, though some like Drax in the UK are betting big on it.

Disclaimer

This article was written, pro bono as a public service, by a human who was sipping home-made cider and writing about something he thinks is important, on a Friday evening, instead of watching Netflix. That human has no money riding on any of this one way or another- he has no EV company stock, nor is he shorting Carbon Engineering etc. But because a human was involved in the writing, there is some emotion in there, as well as the possibility of error. Show me where I’ve gone wrong, with references, and I will gratefully edit the piece to reflect my more fulsome knowledge.

If, however, what you don’t like is that I’ve taken a dump on your pet technology or idea, because of your commercial or ideological dependence on that idea, you should contact my employer, Spitfire Research, who will be happy to tell you to piss off and write your own article.

E-Methane: Exergy Destroyer, On Steroids

TL&DR: grinding up electricity to make heating fuel is just a way to waste energy and capital, by destroying exergy (the potential to do thermodynamic work). It’s obviously worse than just making hydrogen. It is wasteful, and wasteful means expensive. It also means higher emissions than if you did something sensible, like feeding a heatpump.

There’s been a lot of recent news about projects by a firm called TES, in both the US and Canada. A proposed TES project in former Canadian Prime Minister Jean Cretien’s region of Shawinigan, Quebec, has been making major news here in recent days. No surprise, one of the project’s proponents is Jean Cretien’s daughter, France Cretien Desmarais, is a major proponent of the project.

When I wrote my lengthy tome about the various ideas of using hydrogen as an energy export commodity-

Hydrogen to Replace Natural Gas- By the Numbers

– I looked at all the various options for transporting hydrogen- as a gas, as an ultra-cryogenic liquid, as ammonia, methanol, solid metal hydrides, and in the form of hydrogenated molecules (liquid organic hydrogen carriers). All of these looked pretty stupid, due to capital costs and losses. But one real stinker missed the list- the idea of reacting CO2 with hydrogen to make methane. I had to add that to the article later, because it seems to be mentioned more and more often as people contend with the very real problems of distributing hydrogen itself. The simpleminded notion that you can just change which gas is sold in the natural gas network was put to sleep in another of my articles-

The Myth of Hydrogen as an Energy Export Commodity

– and that notion too remains alive, like a zombie, kept that way by the natural gas industry who knows that they are out of business post decarbonization without it.

Some clever folks just say, “Why don’t we put biogas into the natural gas network”? And why not? It’s a mixture of methane and CO2, about equal amounts. While most end-use devices won’t like all that extra CO2, removing it should be easy enough- certainly dead easy compared to removing CO2 from the atmosphere at ~400 ppm…

https://www.linkedin.com/pulse/why-direct-air-capture-sucks-good-way-paul-martin/

Sadly, aside from a few places where agriculture is very intense, there simply won’t be enough. And despite the fact that biogas is made from a waste, by the time you have the CO2 out of it, biogas methane costs a multiple of what we are used to paying for fossil natural gas. It’s also distributed across the landscape, so collecting the source material, producing the gas, and inserting it into the existing gas network is no easy task. Small scale makes it expensive, and physical distribution across the landscape means that you either have to transport waste to larger facilities, or build lots of small, capital-inefficient ones.

So of course the bright sparks who think we’ll be positively drowning in green hydrogen because that’s just frigging inevitable, because electrical grids are hard and whatnot (insert other nonsense as you see fit- the green hydrogen crowd has lots of it, and #hopium smokers the world around seem to be gobbling it up)…well, they think maybe we should react that green hydrogen with CO2 and make…methane.

You know, the exact reverse of the process by which substantially all the world’s hydrogen is actually made today. Whereas we run steam or coal reformers to react these fossils with steam over some catalysts to produce, ultimately, CO2 and hydrogen, these folks want to do the opposite- react CO2 with hydrogen to make…methane.

The Sabatier Reaction

We’ve known about the Sabatier reaction, also known in the industry as “methanation”, for a long time. It is commercially used sometimes as a way to back-treat dangerous CO and CO2, which can destroy fuelcell catalysts, to inert methane, as a treatment method in hydrogen purification.

CO2 + 4 H2 ===> CH4 + 2 H2O

Basically, the reaction involves “un-burning” CO2, by reacting off both oxygen atoms with hydrogen and then replacing the vacant bonding sites with even more hydrogen.

The reaction is spontaneous and exothermic- thermodynamics doesn’t mind if we’re dumb enough to want to do this. And if you were to convert 100% of the energy in the feed hydrogen to the higher heating value of product methane, the ultimate thermodynamic efficiency would be about 78%. That’s actually pretty good, considering.

No real reaction goes that perfectly, though. For instance, another reaction we’ve known about for a long time is this one: one of the methanol synthesis reactions:

CO2 + 3 H2 ===> CH3OH + H2O

That one is also spontaneous and exothermic. And its ultimate thermodynamic limit efficiency is 85% on a higher heating value (HHV) basis-not surprising perhaps, because it wastes one fewer H2 molecule than the Sabatier reaction does, making worthless water. But in reality, you can’t do it for any more than about 60% efficiency in a real plant- which is, unshockingly, the approximate efficiency by which natural gas LHV can be converted to methanol LHV in a world scale black methanol plant.

Another way to put that, is that real methanol systems fed CO2 and H2, only get to about 70% of the ultimate efficiency that thermodynamics sets as a limit. Why is that? Well, lots of reasons, but the big one is that conversion per pass sucks, because the real reaction going on is via carbon monoxide and the water-gas shift reaction pathway rather than directly from CO2 to methanol. That means we end up spending a lot of energy making CO and water out of CO2 and H2, and then running the whole shebang around in a loop, cooling it down, removing the methanol and water products and then re-compressing and re-heating the gas to feed it to the reactor again. Real processes don’t approach thermodynamic perfection very often, and the closer you push them toward that ideal, the more capital cost you end up spending trying to recover energy that would otherwise be wasted.

So: why is e-methane seductive: because a) a giant transmission and delivery system exists for the product, which unlike hydrogen, can actually be fed to that network in any proportion desired b) the reaction is fairly brainless, just requiring a series of fixed bed catalytic reactors with heat and water removal between them. Methanol is a lot more complex in terms of the technology and the plant required.

It’s simple, but that doesn’t stop e-methane from being dumbass. We’ll get there.

CO2 Sources Matter!

If we are planning to make methanol (which might be sensible) or methane (which probably won’t be!) using energy entirely in the form of green hydrogen, and we’re planning to use these molecules as fuels, then it matters a lot where we get the CO2 we use for that purpose.

Some focus on the notion that only the source of enthalpy (chemical potential energy) matters. They think it’s OK to capture fossil CO2 produced by burning or, say, black hydrogen production, and get away with the fact that when the fuel is burned, the captured fossil CO2 ends up in the atmosphere anyway.

I don’t.

We need to stop burning fossils as fuels, because we need to stop emitting fossil CO2 into the atmosphere.

Period.

Getting a 2nd pass on CO2 from burning fossils by capturing (some of it) and using (some of) it in a fuels production process is, at very best, a 50% reduction in the carbon intensity of the original fossil fuel use. That’s just not good enough.

So if you want to call your product an e-fuel, you need, at minimum, to be using pure biogenic or (well…no, this won’t happen) direct air captured CO2.

Evaluation of the TES Shawinigan Project

TES has been granted a 150 MW Hydro Quebec block of power- very green, cold water hydroelectric power with very high capacity factor. Power that should be fed to decarbonization efforts in Quebec- real ones, like electrification of transport, or, at least, fed to hungry electricity consumers in the US so they can shut off their coal and gas fired power plants.

TES apparently plan to add a large amount- hundreds of megawatts more in the form of wind and solar projects that they would build themselves.

Their plan is to convert that electricity to hydrogen, and then react it with biogenic CO2, presumably captured from combustion of wood and wood byproducts in the forestry industry, or perhaps from the CO2 portion of biogas methane etc.

Let’s take this sucker apart and see if it makes sense!

Energy Efficiency Chain for e-Methane

First, we start with electricity. Let’s feed it to an electrolyzer which takes 52.5 kWh/kg of hydrogen. That’s 75% efficiency on the higher heating value (HHV basis), or about 63% efficient on the lower heating value (LHV) basis. That’s a little lower than the 70% LHV basis I usually use in these calcs, but I’ve chosen this for two reasons:

1) To be consistent with what David Cebon used in his hydrogen for heating graphic produced for the Hydrogen Science Coalition (below) and,

2) Because in numerous projects done as a consultant in the past few years, I’ve never, ever seen a real electrolyzer quotation which achieved better than this on a total balance of plant basis. Most fall between 55 and 65 kWh/kg.

Let’s throw in a 1% grid electricity loss, just to show that we didn’t use a big loss here. This is basically an “islanded” project, consuming its own power and electricity made at a nearyby hydro dam.

We’ll also throw in a 95% efficiency (i.e. 5% loss) for hydrogen compression, storage and losses associated with moving hydrogen around on the site.

Next, let’s apply a 92% efficiency, i.e. an 8% loss, to supply the energy necessary to capture and compress the required CO2. That’s a very, very optimistic figure, based on the 2.1 MJ/kg CO2 which is used to capture 78% of the 3.8 bar partial pressure CO2 at Shell Quest. We’re using that figure despite its obvious optimism, just because the figure is publicly available. Any post combustion CO2 capture, and any capture that requires transport of the CO2, is going to take a lot more energy than that!

Now we feed this hydrogen and CO2 to the Sabatier reactor. And remember, best case that converts 78% of the HHV of hydrogen fed, to HHV of methane. Let’s assume that it operates better than methanol, and achieves 75% of maximum theoretical energy efficiency, with the balance going to yield losses, energy to run pumps and compressors, gas separation equipment, cooling to remove the produced water etc. This is based on optimistic comparison to other processes. Based on a ratio of what their project could achieve at best case using the 78% perfect conversion, and how much methane they think they’ll be making, TES seems to be taking this figure as 85%- but hey, they’re bound to be optimistic about their efficiency, I guess. 78% x 75% = 59% overall conversion from hydrogen HHV to methane HHV.

Now we put the gas into the gas transmission system. Compression for transport is about 97.5% efficient, and then transport/distribution itself is about 97.5% efficient per the ANL GREET model. That’s another 95% efficiency or 5% loss in terms of the gas energy we send to customers.

And now, we feed it to a gas boiler or furnace at 90% AFUE.

If we feed 1 MWh of electricity to the front end, we end up with 0.32 MWh of low grade comfort heat, in a home heated with the resulting e-gas. 32% cycle efficiency- but worse than even that…because we fed work (electricity) and got out heat…

But it’s even worse than that when we consider EXERGY, i.e. the potential to do work. And the best way to consider that, is to look at what else we might do instead.

Let’s say we fed the same 1 MWh of electricity into the electrical grid. Distribution is about 95% efficient based on US average data from EIA (i.e. 5% grid loss)- in fact in Ontario where I live, it’s less than 3% loss. The electricity is now already at your home’s meter, where we feed it to an air source heat pump with a coefficient of performance of 2.5 (we’re not expecting 3 out of a unit in most of Quebec, though most Quebecois live along the St. Lawrence, not way up north- just as most other Canadians live within 100 miles of the US border.

1 MWh of electricity then delivers 2.4 MWh of heat into the home. This one is so simple we don’t even need a Sankey diagram to see how awesome it is.

2.4 MWh divided by 0.32 MWh is a factor of 7.5 times. We can heat 7.5 times as many homes for the same amount of electricity if we just leave the molecular middlemen out of it!

And we haven’t even begun to talk about cost!

What Does This e-Methane Cost?

Well, it’s 7.5 times what it would cost to run a heatpump using the same energy, right? Well, it’s not quite that simple- but almost. In fact, it’s far, far worse than that!

Figures in this section and elsewhere are in Canadian dollars unless otherwise noted. $1 CDN = $0.74 USD as of today.

Figuring this out in detail is a little trickier than doing an efficiency chain diagram. But let’s do it, just because we’re bored!

First, let’s assume that TES gets electricity, on average between the 150 MW they get from Hydro Quebec and the wind and solar they make for themselves, at $0.05/kWh. That’d be pretty amazing, but let’s be hopeful here! That’s $13.89 per GJ of electricity, i.e. considerably more expensive than the ~ $7/GJ Energir is reportedly paying today for wholesale natural gas HHV energy. As of today, the US Henry Hub wholesale price for gas is $US2.78/MMBTU which is about $3.70 CDN/GJ. So already, even at an amazing 5 cents per kWh, that’s a lot of money going down the drain, to waste it as heat!

Now, let’s assume a few figures to estimate the cost of green hydrogen. $0.05/kWh x 52.5 kWh/kg is $2.63/kg H2 just for electricity. Add in a $2 million CDN/MW electrolyzer which lasts 10 yrs, which costs us nothing for operating labour or other O&M, and which is given to us by benevolent people who don’t want a return on their investment- they’re satisfied with simple payback when the electrolyzer turns into a pumpkin. And let’s assume a capacity factor for our power of 100%. It won’t really be that high, because only 150 MW is firmed hydropower. But again, let’s be blissfully hopeful here. That drives up our best case price for green hydrogen to $3.82/kg. That’s $27/GJ for hydrogen HHV.

Doubleplusnotcheap!

Now we feed it to a conversion process which makes it into e-methane at 59% efficiency. We don’t know what Sabatier reaction systems cost, so let’s assume they’re free, and have no other operating costs. The result is still $27/GJ divided by 59%, or about $46/GJ of methane HHV. We also need to supply about 0.32 GJ worth of energy to satisfy other energy losses in the chain, but let’s assume they’re supplied as cheaper 5 cent per kWh electricity. That adds another $4.50/GJ, taking us to, round numbers, a blue sky ridiculously hopeful cost of e-methane to TES- NOT to the consumer- of $50/GJ. 50/7 is about 7.1 times the cost of gas currently being paid for by Energir, wholesale.

Relative to the heatpump…well, it’s a lot more than 7.5 times more expensive for energy. Remember, the heat pump eats $13.89/GJ electricity but pumps out 2.4 GJ for every GJ you feed it. So its cost for heating is only $5.80 or so per GJ of heat delivered to your house. Cheaper than what Energir is paying for fossil gas! (But of course, we homeowners pay a lot more than 5 cents retail per kWh of electricity, so let’s forget about how cheap this could be for a second!)

That $50/GJ wholesale cost for e-methane doesn’t include all sorts of things that will be very, very real costs- we’ve just eliminated them from consideration because we don’t have good estimates for how much they’ll cost, or are too lazy to bother to figure them out. And it doesn’t include profit, or any return on investment for anyone. It assumes the project is run by altruists.

And, as it turns out, it doesn’t matter. Even without those unknown costs in there- all of them at zero- the result is ridiculously expensive e-gas.

So…WTF Would We Ever Do This?

It turns out that the motivation behind this project is likely a mandate by Energir to use a certain percentage of low or zero emissions gas in their network. And they can’t get enough biogas…apparently…even though it is vastly cheaper than this e-gas ever will be.

And the other reason is as clear as day to me: subsidy harvesting. One can imagine not only attracting a substantial “tax credit” from the federal government for making green hydrogen (effectively reducing capital cost by getting the government to pay for it!) , then more still for making green gas out of it- and then it wouldn’t surprise me if they thought they could get CO2 capture credits of some kind here too. Nevermind the fact that any CO2 captured, ends up in the atmosphere when the gas is burned…

Well, there you go, folks. e-methane is an exergy destroying machine on steroids. And if it is built, this TES project will be a very efficient extractor of money out of likely both the federal and provincial governments AND out of the pockets of Energir gas consumers.

What it isn’t, is a sensible decarbonization strategy.

References:

1) Data from real projects for electrolyzer efficiency, proprietary (I can’t share the quotations with you, sorry)

2) Moioli et al, Renewable and Sustainable Energy Reviews, 107, 2019

3) My own calculations for the ultimate conversion efficiency for methanol and methane from CO2 and hydrogen, validated against ref 2) above

4) Experience with e-fuels projects in terms of approach to ultimate energy conversion efficiency, again confidential (most figures in the academic literature are very significantly over-estimated relative to reality)

Disclaimer: This article was written by a human, and humans make mistakes. If I’ve made one, please feel free to call me out on it and to provide references if possible to set me right. I’ll be grateful for the correction.

If I’ve just upset you because I’m shitting on your pet idea, feel free to contact Spitfire Research Inc. They’ll be happy to tell you to piss off and write your own article.

Breakthrough in Electrolyzer Efficiency!

“FOR IMMEDIATE RELEASE

🔬REVOLUTIONARY BREAKTHROUGH SETS HYDROGEN ENERGY IN A WHOLE NEW LIGHT

[City, Date] – Today marks an unprecedented achievement in the sphere of renewable energy! We’re incredibly excited to announce a thrilling breakthrough in hydrogen electrolysis that could totally redefine the landscape of the global energy sector. Brace yourselves, friends of tech, because you’re about to be blown away by this game-changing, phenomenal advancement.

This isn’t just a step forward; it’s a colossal leap towards a future brimming with sustainable energy! Our team of wizard-like scientists and technical magicians have unlocked the secrets of hydrogen electrolysis, achieving unprecedented levels of energy efficiency that were previously considered the stuff of dreams.

The newly discovered process, affectionately dubbed “Hydrogen 2.0,” operates at breathtakingly high efficiency levels. We’re not just talking 20%, 50%, or even 80%… Nope! Our revolutionary Hydrogen 2.0 is astonishingly hitting near-perfect efficiency rates! Imagine the capabilities of an energy source that delivers virtually no energy waste – it’s mind-boggling!”

(The preceeding delicious #hopium emission was courtesy of ChatGPT as expertly wrangled by human intelligence Michael Barnard)

In the past few years there have been at least two prominent and at least somewhat credible claims that people have 95% (HHV) efficient electrolyzers working in the lab.

So that’s my argument against hydrogen on the basis of inefficiency shot to pieces, isn’t it? Guess it’s time to pack up the @hydrogen science coalition and jump on the hydrogen as a fuel bandwagon, eh?

Let’s be clear: the problem with hydrogen isn’t that electrolysis is inefficient, or fuelcells are inefficient, or storage is inefficient. The problems with hydrogen as a fuel or energy storage medium are a) exergy destruction b) too many steps, each with efficiency limits and c) the properties of the H2 molecule.

Exergy Inefficiency

Exergy has a more complex definition to a thermodynamicist, but to a layperson or an average engineer, it’s safe enough to just call it “the potential to do work”. While a joule of room temperature heat and a joule of electricity are both 1 joule of energy, the former has ZERO exergy and is basically worthless if you have more of it than you need, and the latter is nearly pure exergy. You can convert electricity with very high (nearly 100%) efficiency into thermodynamic work, i.e. mechanical energy. As Michael Liebreich says, riffing on Orwell’s Animal Farm: “All joules are created equal, but some joules are more equal than others!”. Or as I say, “Committest though NOT the 2nd Sin of Thermodynamics!”. The 2nd sin is to confuse a joule of heat with a joule of work as if they’re of equal value- rather like confusing an American dollar with a Jamaican dollar because they’re both units of money measured in dollars!

I have a device which can convert electricity to 1000 C heat with 100% efficiency! Is that magic? No, the device is called a resistance heater. Converting pure exergy to even high temperature heat with 100% efficiency is no problem, because that heat has a lower exergy value. The 2nd law says, “that’s fine- thou shalt pass”.

On the flipside, one can use a joule of work to PUMP 3 joules of heat from a cold place to a hot place. The 2nd law is OK with that too, with the temperatures of the hot and cold places determining the maximum efficiency (called, for heat pumps, a coefficient of performance).

An electrolyzer is no more magical than- and in fact, in thermodynamic terms, it’s fairly similar to- a resistance heater. It converts pure exergy (electricity) into a fuel, which is chemical potential energy- a proxy for heat. That process is in the 2nd law’s natural direction, the direction of increasing universal entropy and decreasing useful exergy.

This is the fundamental problem with using hydrogen derived from electricity, as a fuel or energy storage medium. Even at high ENERGY efficiency, making hydrogen from electricity is a massive step backward in EXERGY efficiency.

The current state of the art of water electrolyzers is about 83% HHV (ultimate, thermoneutral) efficiency on the stack level. That means to produce 1 kg of H2 with a HHV of 39.4 kWh/kg- the total heat energy produced when you burn that 1 kg again, including the (useless in exergy terms) 6.1 kWh/kg worth of heat of condensation of the product water vapour- you need to put in 39.4/0.83 or 47.4 kWh of electricity.

Of course a hydrogen plant contains much more than just an electrolysis stack- it has “pumps and tanks and sh*t” too- as my old boss used to say about stuff that looks complicated but really is pretty routine. That stuff- compression equipment, hydrogen deoxygenation and drying, electrolyte management, heat rejection, water treatment etc. etc., a) consumes electricity too, b) costs money and c) is already mass produced, so learning curve savings in cost or big improvements in its efficiency are both unlikely. Add in these “balance of plant” and “outside battery limits” energy uses and hydrogen costs somewhere between 50 and 65 kWh/kg to make from water.

Scaling Example #2: Water Electrolysis

The Efficiency Bargain

Recent claims by two firms- Hysata, with a capillary water electrolyzer, and H2Pro with a complex multi-stage semi-batch electrochemical water splitting scheme, are that they can make 1 kg of hydrogen for 39.4/0.95 = 41.5 kWh. That’s a savings of 5.9 kWh/kg. What percent improvement that is, depends on what denominator you choose, and is hence not all that useful.

These new electrolyzers are both a) new, so no learning curve yet to make them cheaper and b) more complex than state of the art electrolyzers. Both are early stage, i.e. low technology readiness level. To know if either will EVER be useful for making hydrogen at scale, we’d need to know lots and lots of things:

  • capital cost now, ie. complexity, ease/difficulty of manufacture, raw materials cost etc.
  • how the capital intensity per kg of H2 produced might be reduced when production is done at scale (ease of mass production, basic complexity (how simple is it, and can it be made simpler to reduce cost), ability to scale rather than number up units etc.), and threats to the supply chain (availability of catalytic metals is a big risk for PEM units for instance)
  • durability, i.e. how many hours on stream the stack or catalysts will last before requiring replacement
  • efficiency loss: how quickly the catalysts or other components lose effectiveness and hence drop efficiency
  • etc. etc. etc.

Some of these things won’t be known until a unit has been in industrial service for ten years. Some, we can get good guesses at fairly soon, but only if we’re under an NDA with the company so they open their technical kimono and show us the technology away from the investors and stock promoters, warts and all- so no, you’re not going to find that stuff in a media article!

The fundamental bargain here however is really simple: how much extra cost is it worth to save 5.9 kWh/kg H2?

Taking an electrolyzer which is found in working order, free in a ditch somewhere, which magic elves install free of charge on borrowed land, and with a system efficiency of 50 kWh/kg, to make $1.50/kg hydrogen, it would need to be fed electricity at 3 cents per kWh, i.e. $30/MWh. Add any capital cost at all, and this price of electricity must fall even further, or the price of hydrogen must rise to pay back the capital investors, and the non-magic elves who expect a salary, and the people who don’t give away land for free. If the capital is more than zero, then it will also matter how frequently that electricity is available at a low cost. Even if it’s free part of the time, if it’s not cheap most of the time, your electrolyzer is going to make expensive hydrogen.

5.9 kWh x 3 cents = about 18 cents per kg. You’re not going to pay for much additional capital cost with those savings. Mind you, the 50 kWh/kg electrolyzer is already a pretty expensive beast, because it’s running at a low current density to be so efficient. Real ones you can afford are going to be closer to 60 kWh/kg on a system basis. But who knows what current density Hysata and H2Pro’s claims are made at? I wouldn’t trust the figure even if I could find it in print. And we’ve already established that the capital cost will be higher, because these systems are more complex than the current state of the art- in one case because of complex microstructure (capillaries) and in the other, because it’s a sequential semibatch operation, with oxygen evolution happening separately from hydrogen generation. That takes more “tanks and pumps and valves and sh*t”…

So: are Hysata or H2Pro “breakthroughs” that will revolutionize hydrogen production? Doubtful. They may, or may not, marginally help. But they don’t fix the fundamental problem with electrolysis- they don’t stop it from being, fundamentally, a massive destroyer of exergy.

Steam Electrolysis: SOECs

If you electrolyze steam rather than water, you can actually make hydrogen for even less than 39.4 kWh/kg input electrical energy. You can actually take some heat and convert it to hydrogen chemical potential energy. Of course the device is a stack of metals and ceramics glued together with glass, which operates at around 700 C, so you’re not getting off scot free here. Even if you can find somebody who will boil water for you for free, rather than paying another 6.1 kWh/kg H2 to do that, you have the problem of running at 700 C. And given that 7/8 of the mass coming out of the electrolyzer is oxygen, recovering heat from what amounts to a cutting torch is, well, tricky. SOEC stacks are small, don’t like thermal cycling so have to be electrically heated to keep them hot when they’re not operating, and today cost considerably more per MW of capacity than water electrolyzers- for reasons that should be obvious. Are SOECs a magical solution? Depends- does your process need both hot oxygen and hot hydrogen? Then, maybe. Otherwise, doubtful in my view, unless somebody makes a huge leap forward in making SOEC run efficiently several hundred degrees cooler.

Cycle Efficiency

The problems with hydrogen as a fuel or energy carrier show up when you do a cycle- from electricity to hydrogen, hydrogen to storage, and storage to a fuelcell or turbine or other device to make electricity again.

Of course the ridiculous commentators say that the cycle is 100% efficient! And they’re right- it’s 100% efficient at turning electricity into heat, most of which is worthless. Sadly, a chunk of heat (electrolysis waste heat, and compression or liquefaction waste heat, or ammonia/methanol/LOHC hydrogenation/e-LNG waste heat, is made where you already have energy in excess (and hence are throwing away electricity). So yeah, that waste heat is GONE- it rarely has a meaningful use, except perhaps in complex process units i.e. with the waste heat used to run the Rube Goldberg apparatus known as direct air capture or the like. Affording the capital to recover this heat is a different matter, and a value proposition there is absolutely NOT guaranteed. The smaller the scale, the less likely that source heat recovery will be useful.

Using best case figures: electrolysis at 83% HHV efficiency is really about 70% LHV efficiency (subtracting the 6.1 kWh/kg of heat energy which no fuelcell or engine can put to use). Best case, compression for storage is about 90% efficient, at scale- at smaller scale, this efficiency falls rapidly. And the best case for either a fuelcell or combined cycle gas turbine power plant is about 60% on a LHV basis. 0.7 x 0.9 x 0.6 is 37%, i.e. buy 3 kWh, get 1 back. That’s just fundamentally a terrible battery- even worse, because the energy density of hydrogen per unit volume is absolutely terrible. And on top of that craptastic efficiency, you end up needing to pay for a bunch of expensive capital equipment. Note there’s nothing in that simple calc for transmission of electricity, transmission of hydrogen product, or innumerable other energy-sucking factors in real systems. It’s an idealized best case. And no, changing that 70% LHV efficiency to 80% (i.e. 95% HHV efficiency) doesn’t help all that much- the cycle increases to 43%. On the same basis, a lithium (or sodium) ion battery is 90%. And that battery is very, very much simpler.

A nice visual example, because people like pictures: here’s David Cebon‘s graphical explanation of why it is so much more sensible to use the exergy of wind electricity to pump heat into homes, than to use it to make hydrogen to replace fossil gas in existing boilers. There we’re talking about a ~ 5-fold difference in useful energy delivered per joule of feed energy.

Poor cycle efficiency is what kills hydrogen’s use as a fuel, whether for transport or heating or what have you. Poor efficiency which is NOT offset by much greater effectiveness (i.e. ease of storage, transport or use of energy) is just a recipe for economic failure. It’s putting money into two piles on the floor and setting one of them on fire. That might make you money under some rare circumstances, but generally only if the money you’re burning, isn’t yours!

Disclaimer: I’m human and so I make mistakes. I don’t know everything, either. Where I’ve gone wrong, provide me with good references to the contrary and I’ll amend my text with gratitude. Don’t like it because I’m slaughtering your precious idea with my analysis? Feel free to complain to Spitfire Research Inc., who will tell you to shove off and write your own article.

Scaling Example #2: Water Electrolysis

Old electrolyzer stacks from Norsk Hydro, now NEL, 1920s

Scaling Object Lesson #2: Water Electrolyzers For Hydrogen Production

We learned about vertical scaling in the 1st article in this series:

Economy of Vertical Scale

…and about horizontal scaling or “numbering up” in the 2nd:

Horizontal Scale- Numbering Up

Now we’ll use these tools to examine the scaling future of an extremely important decarbonization technology: electrolyzers for producing hydrogen from renewable electricity.

My readers will know that I think hydrogen is a massive decarbonization problem, and that I think we must focus our efforts on making green (electrolytic) hydrogen to replace the 98.7% of the stuff that is made from fossils without carbon capture- the ultra-black hydrogen that dominates the market today.

Hydrogen From Renewable Energy- Our Future?

In a decarbonized future, we’ll need a lot of green hydrogen, even if we aren’t stupid enough to waste any as an inefficient vehicle or heating fuel! I estimate that 90 of the current ~ 120 million tonnes/yr of hydrogen we use today, is durable in a decarbonized future. And in reality we’ll need more than that, because there are some uses for hydrogen as a molecule which are also a very good idea: for instance, using H2 to replace the carbon monoxide used in the direct reduction of iron ore to iron metal.

Replacing that 90 million tonnes of H2 per year would take a monumental effort. Optimistically, it would take 4500 TW h of green electricity– more than twice as much as all the wind and solar made on earth in 2019. Given that today we’re making less than 0.03% of world H2 production by the on-purpose electrolysis of water, we’re really at ground zero on the important task of decarbonizing hydrogen itself.

If we had renewable electricity available to us at 100% capacity factor, we’d need only ~ 513 GW worth of electrolyzers to make that hydrogen- but since renewable electricity isn’t available with such high capacity factors, we’ll really need 1000-1500 GW of electrolyzers.

How much on-purpose electrolyzer capacity is there on earth today? Less than 1 GW. We need to increase electrolyzer capacity by at least 3 orders of magnitude and probably more.

Hmm: how can we apply what we learned about vertical and horizontal scaling to this most important decarbonization problem?

Electrolyzer Basics

There are two main water electrolysis technologies which are front-runners today: the alkaline electrolyzer, and the proton exchange membrane (PEM) electrolyzer. They differ in details, features, benefits, disadvantages etc in important ways, but for our purposes we don’t need to worry about that. Let’s look at the basic components of an electrolysis system.

The electrolyzer itself consists of a “stack” of electrolysis cells, each with an anode and a cathode (and many other parts, depending on which technology). Cells are arranged in physical parallel, meaning that each cell is fed water/electrolyte and the products (hydrogen and oxygen gas) are collected from each cell.

(schematic of an electrolyzer stack- image credit, IRENA)

The cells may be arranged electrically in series, parallel, or series/parallel arrangements to allow us to select DC current and voltage inputs of a manageable level. High currents mean big conductors, expensive power controls, and high ohmic losses- high voltages mean lower currents, but also the potential for currents flowing where we don’t want them to- so we are involved in a balancing act.

Electrolysis is an area-based process. The key parameter for electrolyzer design is current density, i.e. the current, in amperes, which flows through each unit of electrode/cell area. Lower current density means lower voltage per cell and hence higher efficiency, but also means more capital cost per unit of H2 production (or power input) because each unit of electrode area produces less value (less hydrogen) per unit time.

While we could build complete cells individually, and connect each one up to the others with individual tubes and wires or buss bars, that would be very expensive- and we’re smarter than that. Designs vary, but you won’t go far wrong as a basic mental model to think of a stack of plates held together with draw bolts, with internal manifolds and process connections at each end, arranged rather like a plate and frame heat exchanger.

It is advantageous to produce the hydrogen product under pressure, so that less mechanical compression is needed prior to transport or storage of the bulky gas. While pressure forces the equilibrium the wrong way (back from H2 toward water) which costs us some voltage, it also makes the gas bubbles smaller and hence leaves less electrode area blocked by nonconductive gas. Smaller bubbles mean lower current density and hence higher efficiency- to a limit. That means we get a certain amount of gas compression out of an electrolyzer basically “for free” in energy terms- very desirable! Unfortunately, pressure acting on a unit of area generates a force that wants to separate our plates and make the electrolyzer leak- so the bigger we make each plate, the stiffer it must be and the larger and more numerous the bolts that draw the plates together. Ultimately, this basic physics puts practical limits on how big we can make each plate.

Balance of Plant

The electrolyzer stack or stacks are only part of an electrolysis plant. Everything outside the stack which supports it, is called the “balance of plant” or BoP.

(balance of plant for an alkaline electrolyzer: image credit, IRENA)

Each electrolyzer needs a supply of pure water- at least 9 kg per kg of H2 produced. You can use freshwater or seawater, but in either case you must use reverse osmosis to purify it first- a process which takes a trivial amount of electricity (only 0.035 kWh/kg of H2 even starting with seawater) relative to the 50 kWh/kg it takes to make 1 kg of H2 from water. Impurities in the water can (significantly) sap efficiency by carrying stray currents, can make products like chlorine which contaminate the product gases and destroy materials of construction, deactivate cell catalysts etc. Water purification is a no brainer here- and trying to electrolyze dirty or saline water as a way to make hydrogen, is a fool’s errand.

Electrolyzers need DC electricity of controlled current and voltage. Large variable output DC power supplies referred to as “rectifiers” (but much more complex than a bunch of diodes!) are therefore required, along with all their safety gear, measurement instrumentation and controls, and heat removal systems (because these power supplies are not 100% efficient).

Electrolyzers themselves are not 100% efficient, which means that they convert some of the electricity they are fed, into heat. While a little heat is good (improves efficiency), too much wrecks materials of construction or boils the feed water. Accordingly, heat removal systems are required, and the amount of heat generated at scale is a) is not trivial and b) generally produced in places which already have excess energy available, and which hence have little use for low-grade heat. That means we need pumps and heat exchangers to manage this heat, and yet more heat exchangers to reject this heat to the atmosphere.

The product hydrogen is saturated with water vapour and also contains some oxygen. Generally the hydrogen is passed over a catalyst which burns out the oxygen, forming more water. Drying is accomplished in stages with compression and cooling, and for some processes, more complex drying (based on regenerable adsorbents) may be required. So here too, we’re talking about catalyst beds, heat exchangers, compressors, refrigeration equipment, adsorbent beds etc.

The product oxygen is usually vented, but if it is to be compressed and monnetized, it too needs drying, hydrogen removal and compression.

Finally, the product(s) need to be compressed for transport or storage. Whereas electrolyzers might operate at 30-70 bar, storage is generally at 250 bar or higher. That’s more compressors, piping and storage tanks.

“Outside Battery Limits” (OSBL) Equipment and Infrastructure

An electrolysis plant is like any chemical plant making any other chemical product, in that there are support systems outside the “battery limit” of the chemical plant itself. Some examples include:

  • electrical substations, switchgear etc.
  • Control and data acquisition system and human/machine interface
  • pipeline connections, trailer loading facilities
  • water supply and wastewater management
  • emergency relief systems, flares, vent stacks etc.
  • Buildings or weather enclosures
  • facilities for operators or maintenance staff
  • roads, parking, civil works

That’s just a partial list- but every such project has to take the OSBL into account, and pay for it.

Scaling of Electrolysis Systems

Assuming that what we want is to make hydrogen as cheaply as possible per kilogram, how should we proceed with scaling up an electrolysis system?

From the discussion about the basic physics of a cell and cell stack, a few things are clear:

  • cells are repeating identical units consisting of parts which we might mass produce
  • making each cell larger in area will allow each cell to consume more current and hence produce more H2
  • making each cell larger in area makes it more likely to leak and requires stronger materials
  • arranging cells in fluidic parallel in stacks makes more sense than building innumerable tiny cells and connecting each one

The first point gives us some hope that Wright’s Law can come to the rescue. It is entirely possible to imagine cell components being made in automated factories, and then robotically assembled into cells, and cells into stacks, in a true mass-production environment. And as we do that, with every doubling of production, we should expect the units to get cheaper.

It’s fairly clear that cells of larger electrode area are going to be desirable, but that larger cells will require stronger materials and will be more likely to leak. An optimum size should exist, but that size will vary depending on many things, including the limitations of our mass production scheme.

It’s also fairly clear that it would be desirable to stack up as many such cells into a “stack” as practical, so we have as few stacks as possible- but that there will likely be a practical physical maximum based on mechanical properties, fluid mechanics, and dimensional limitations for transport etc.

And so, the electrolysis industry has concluded. While stack sizes are pushed upward yearly, right now the biggest single stack has a capacity on the order of about 10 MW of input power. A 1 GW electrolyzer therefore would consist of 100 such stacks, arranged in physical parallel, likely in a number of “trains”.

So: what’s our scaling conclusion about electrolyzer stacks? I think we can conclude:

a) Wright’s Law will likely be applicable to the stack

b) since just to replace black hydrogen, we’ll need to increase the capacity of electrolyzers on earth by at least 1000x, there’s lots of room for Wright’s Law to run down the cost of each stack

c) both the cells and the stacks of cells will likely have an optimum size, but people will be motivated to increase that optimum size by clever design

d) the optimum size of stack will require that multiple stacks be “numbered up” to achieve plants of sufficient scale

a) and b) are good, hopeful signs for future electrolyzer stacks to become cheaper with time- assuming somebody will pay for the initial stacks which are expensive per unit of production and not mind doing so.

d) however means that projects of substantial size will involve lots of stacks in physical parallel, and that means that there will be limited economy of vertical scale for the electrolyzer portion of the project

What about the balance of plant?

That consists of “tanks and pumps and sh*t”, as my old boss used to say whenever he was confronted with something that looked complicated and scary, but wasn’t really. Conventional stuff, nothing magical. Nothing we shouldn’t be able to scale vertically to kingdom come. And as we scale that stuff- as an electrolysis project gets bigger in capacity- we should expect the marginal cost of the balance of plant to drop per kg of H2 for the good reasons given in my first article in this series. However, we should also expect nearly zero Wright’s Law benefit in relation to the balance of plant. The same for the OSBL: as a proportion of cost per kg of H2, it should drop as the scale of the project increases, but there should be little to no Wright’s Law learning curve to save our bacon. It’s not like pumps, tanks, heat exchangers, buildings, parking lots, electrical substations etc get cheaper as we make more of them- we’ve made too many of them already, and getting to the next “doubling” takes decades.

The Current State of Electrolyzer Scaling

The major players in electrolyzer manufacture have grown up making fairly small units. Prior to the most recent hydrogen #hopium pandemic, the whole role for electrolysis was either to make high purity hydrogen for specialist applications, or to make quantities of hydrogen to rescue users of small quantities of the gas from the high prices being charged by gas suppliers for tube trailer deliveries from a commercial hydrogen plant. Anybody who needed hydrogen at a meaningful scale, simply bought their own small SMR and made it themselves instead from much cheaper fossil gas.

Often, electrolysis supported pilot projects or provided hydrogen as a utility to an existing facility. Accordingly, many of the electrolysis suppliers designed modular products, often based around “seacans” (shipping containers) which served as both environmental enclosure and support for the equipment. Some units were self contained in a single container, while others required several containers for a complete unit.

(container modular electrolyzer system: image credit- Plug Power)

What do you think about the idea of mass producing containerized complete small electrolyer systems in containers? What are the economic prospects for such a design?

In my opinion, based on the type of analysis we’ve used in the past two articles, the prospects for such an approach are very poor indeed. I see this design as a hangover from the industry’s history.

While the stacks will still have Wright’s Law cost learning benefit, complete containerized packaged systems could benefit from factory fabrication but likely would have minimal to no Wright’s Law learning based cost reduction benefit. The economy of vertical scale for the balance of plant would be abandoned due to the very small maximum scale of complete units stuffed into containers of a limited size, and the resulting marginal capital cost per kg of H2 would be higher than necessary. Furthermore, shipping containers, though themselves mass produced (for use AS shipping containers…) are an inefficient use of steel, an inefficient way to enclose space relative to constructing a building, they offer poor access for operation and maintenance, and are (greatly!) suboptimal in size relative to (considerably) larger modular frameworks which can ALSO be moved by road and sea to most locations. In modular systems, the optimal size of a module is the biggest piece you can move down the road without excessive “heroics”, so you have to re-assemble as few modules as practical on site: this maximizes one of the key benefits of modularization, which is minimizing expensive site work by doing as much in the factory as practical.

The ridiculous extension of this approach is the proposed path to scale of Enapter, a company developing a technology called anion exchange membrane electrolysis. Though the AEM technology has an interesting combination of desirable properties of both alkaline and PEM units, with some of the downsides of each removed, Enapter’s publicly announced strategy is to mass produce complete 2.3 kWh electrolyzers, each including its own complete balance of plant. Thousands of such factory mass-produced units would be physically paralleled to produce an electrolysis project at scale. Sadly, I think this is an object lesson in how not to scale up an otherwise potentially promising technology. It shows to me a lack of understanding of fundamentals of engineering economics.

https://www.rechargenews.com/energy-transition/-our-unique-aem-electrolysers-will-produce-cheaper-green-hydrogen-than-any-rival-tech-/2-1-1042573?utm_content=buffer0a93c&utm_medium=social&utm_source=linkedin.com&utm_campaign=buffer

Fortunately, there are smarter people in the electrolyzer space, both among the market leaders and a number of their rivals. They have a clear view of what it would take to make electrolysis cheap enough to make cheap green hydrogen at scale, and are pursuing development projects for equipment that are consistent with good engineering economics. Some of them are even smart enough to be Spitfire Research customers! But in the interest of maintaining confidentiality, I won’t mention their names, unless they want to “out” themselves in the comments.

Insights for the Future Cost of Green Hydrogen

To become truly inexpensive, truly green hydrogen requires the following things:

  • a) very cheap renewable electricity available at high capacity factor, which means hybrids of wind and solar in places which have sunny days and windy nights
  • b) projects of very large vertical scale
  • c) electrolysis plants that are inexpensive at scale
  • d) to make green hydrogen production into a business, you also need a way to get the green hydrogen to market.

(Sharp readers will notice that I never mentioned efficiency- and that might make some people suspect I’ve been smoking some #hopium myself. Why is efficiency not on that list? Because the existing state of the art of electrolysis is already 83% HHV efficient, which sadly is only 70% LHV efficient- though hard to afford at that low current density. The incremental benefit from 83% to 100% on an HHV basis- the limit for water electrolysis set by thermodynamics- is, in my view, much less important than the other factors!)

To achieve a), you need large hybrids of wind and solar, located far away from electricity markets (or else you’ll simply make and sell electricity instead!)- locations such as western Australia, Chile etc. That unfortunately collides with d)- locations far away from electricity markets are also far away from places which can use hydrogen, and moving hydrogen across transoceanic distances is a bear of a problem. Accordingly, those projects will need to make something you can move, such as ammonia, direct reduced iron,, methanol or the like. And, hopefully, we’ll be smart enough not to waste those materials as ways to make hydrogen again…

The Myth of Hydrogen as an Energy Export Commodity

To achieve c), you need somebody willing to buy expensive electrolyzers- and the expensive hydrogen they produce- sufficiently to get electrolyzer production far enough along the Wright’s Law learning curve to make the cells and stacks cheap enough. That’s possible but it will take deep pockets- our public pockets. So it’s my hope that we aren’t stupid enough to waste any of that precious, expensive but truly green hydrogen on dumb uses that are better served by electrification directly or via batteries, or which can be eliminated, or which can be solved more effectively by other means (biofuels etc.)

What you also need is b), ie for the balance of plant and OSBL to be done at large vertical scale, because it won’t be subject to Wright’s Law and hence won’t get cheaper as a result of learnings. And sadly, there’s only so much that vertical scale can do to reduce the costs of this part of the cost of a total hydrogen plant.

Will green H2 get cheaper? Absolutely! But only because it is insanely expensive at the moment.

Will it get cheap enough? Depends on what you mean by cheap enough, and for what purpose.

Will it get cheap enough to replace black hydrogen? That depends more on what we do in relation to carbon taxes and emission bans than it does in relation to the scaling of electrolysis technology. I dearly hope so- our lives are depending on it, if we want to keep eating that is. Dumping CO2 to the atmosphere for free, or nearly free, is a giant subsidy on the backs of our childrens’ futures that we must END, TODAY.

Will it get cheap enough to go head to head with the electricity it is made from? No. That should be obvious.

Will it get cheap enough to use as a fuel, for transport or heating? I doubt it. I think there are better options that will achieve decarbonization of these functions, at far lower cost to society. That goes even moreso for so-called e-fuels derived from hydrogen. Fighting thermodynamics all the way back from water, CO2 and electricity is a fool’s errand- one that should be undertaken only if we are both rich and desperate.