ICCT’s Hydrogen For Aviation Perspective Is Deeply Wrong As Well

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The International Council on Clean Transportation (ICCT) is a US-headquartered think tank with offices globally. It’s been around since 2001. It was founded with noble ideals and funding from progressive and climate-focused foundations including the Hewlett and Packard family foundations and the Energy Foundation. Its mission and vision is to provide clear policy guidance based on evidence to more rapidly address climate change.

But it’s gone astray somehow regarding hydrogen. This came to my attention when they published a fatally flawed truck transportation total cost of ownership study that included the remarkable conclusions that hydrogen trucking would have energy costs only slightly more than battery electric trucking, that by 2030 it could be cost competitive with diesel and that by 2050, hydrogen trucking would be only 10% more expensive than battery electric options. The lead interactive graphic and conclusions were clearly wrong at a glance, as many transportation experts pointed out.

They had put multiple thumbs on the scale for hydrogen including big subsidies, cheaper electricity, no profit requirements and more, and further had scattered these thumbs across three different papers, making it difficult to assess how they had gone so wrong. That it was wrong should have been apparent at a glance to the two authors and multiple ICCT reviewers, yet it passed into public record. Strong criticism, including by me, led to them rerunning the model and quietly changing the infographic and conclusions without actually acknowledging that they had done so and that their initial publication was completely wrong, merely stating that there had been interest and they had added an addendum.

A month after the trucking report, they published an equally odd report on maritime decarbonization with hydrogen and sails. Assessment of that study found that it had modeled rigid sails on ship types where they clearly weren’t viable, but that wasn’t the biggest challenge. Once again, hydrogen reared its molecular head. The costs of liquid hydrogen shipping used a per ton rate for hydrogen that was solely the cost of electrolyzing it without any compression, distribution or liquification costs, or once again any profits for anyone in the supply chain. This was clearly stated in the document they referenced, and the price point of $4.30 per kilogram was clearly unburdened with the more than doubling that an even remotely accurate cost accounting would provide. That cost point was clearly low regardless, as it ignored balance of plant, and had lower prices for electricity than US industrial rates.

But it got worse. The reference document in question, another ICCT paper entitled Current and future cost of e-kerosene in the United States and Europe from March of 2022, had future hydrogen manufacturing costs that were both extraordinarily low and unsupported by the data that should have made them up. In 2030, they were asserting a price point that equated to 100% efficiency for manufacturing hydrogen from electricity. In 2040, the hydrogen price point made it clear that 10% of the energy in the hydrogen was coming for free through unstated means. In 2050, it was 50% of the energy, with a per kilogram price point of manufacturing of only $1.6 per kilogram.

While there are illusions that this might be possible, they depend on free electricity and effectively free electrolyzers and plant equipment, neither of which were referenced in the study, or on very large subsidies, which once again were not included in the supporting material. The US IRA is not mentioned in the report. It could have been an artifact of the discounted cash flow model they use, except that the cost of electricity barely dropped, while the cost of hydrogen plummeted, and they were, to be clear, electrolysing water to make hydrogen using electricity.

So the maritime decarbonization material that the ICCT is publishing is deeply flawed when it comes to hydrogen pathway costs as well. And when we say e-kerosene, what that translates to is aviation fuel. Is this one report an aberration from the ICCT on the use of hydrogen and synthetic fuels made from it? Unfortunately, no.

Let’s finish off with the 2022 e-kerosene report before moving on. There are some other odd assumptions in it. They cite the source of $40 per ton CO2 as either flue carbon capture or direct air capture, both of which have capture costs double that price point in the case of flues and 10 to 25 times in the case of direct air capture. They include no distribution costs for CO2 that are apparent either, and CO2 is a bulky gas that’s expensive to ship, with truck delivered costs typically in the $100 per ton range even when the source is geological stores of CO2. Piping CO2 requires converting it to dense or supercritical phases and is highly energetically expensive as well. The cost point of CO2 is unsupportable, in other words, another thumb on the scale for e-kerosene.

This cost work up is the absolute best case for manufacturing synthetic kerosene using direct air capture, electrolyzed hydrogen with dirt cheap low-carbon BC industrial electricity rates and the same chemical engineering process that the ICCT paper uses. I worked this analysis up in 2019 as part of my series on Carbon Engineering, one of the many carbon engineering technologies I’ve assessed deeply.

You’ll note that with every benefit of the doubt given to Carbon Engineering’s solution, the price point for CO2 per ton is almost three times that used by the ICCT paper. Also as a note, the price point for electrolyzed hydrogen is from a US study that suggested it might get as low as $5 per ton, which is still very optimistic and once again beneficial to the e-kerosene cost case. A realistic cost of hydrogen manufacturing at scale is much more likely to be in the $6-$8 per kilogram range with balance of plant, and as you’ll also note, the cost of hydrogen is 50% of the cost of e-kerosene.

At that, in this absolute best case scenario with an unrealistic assumption of zero efficiency losses along the chemical processing journey, the cost per ton of e-kerosene was close to $1,600 USD. Even with artificially low CO2 and hydrogen costs and 100% efficient chemical engineering, just the cost of manufacturing with no distribution costs or profits in the supply chain was 2.3 times higher than the current cost of Jet A. Actual adders would make it four times the cost.

The ICCT study makes some likely to be optimistic assumptions about electrolyzer efficiency gains and cost decreases, but once again has no balance of plant. The assumption is that it’s an integrated hydrogen electrolysis to chemical process manufacturing plant, and that’s a good one, but there is still balance of plant including dehydration, and the figure of $1.6 per kilogram is still unsupportable. And you won’t be getting electrolysis, CO2 flue capture and kerosene manufacturing all in the same place.

Unsurprisingly, they find that e-kerosene in 2050 would be about $1,100 per ton, a deeply unrealistic cost point. Also unsurprisingly, all of these thumbs on the scale lead to e-kerosene being very close to cost competitive with biofuels and Jet A in 2050, a completely unrealistic result.

Is this the only problem with ICCT’s aviation-related studies? No, but where did the problem start? Let’s go back to a pair of 2018 ICCT papers, The cost of supporting alternative jet fuels in the European Union. and Decarbonization Potential of Electrofuels in the European Union. Once again synthetic kerosene with electrolysed hydrogen is being assessed against other alternatives. These studies appear to be fairly rigorous and make note that synthesized paraffin price points would require massive use of synthetic diesel on roads as well as very high subsidies in order to achieve lower costs. Electrified aviation isn’t mentioned, which is probably reasonable in 2018 because the scope is jet fuels.

Other more recent ICCT papers share a propensity to assume that projections of massive growth of civil passenger miles would continue at 4.5% per year, aligned with IATA and major aerospace companies like Boeing. A 2021 paper excludes the short- and mid-term impacts of COVID-19 from its projections. As passenger aviation is relatively flat in the developed world and massive diversion of potential growth to high-speed rail is occurring in China especially, with much slower growth rates in other developing countries, I consider these projections and the fuel demands based on them to be hard to consider reasonable, but while extreme, are at least defensible.

My projections for growth, iterated after discussions with international aviation demand projection experts, is much more gradual. It includes COVID-19’s short- and medium-term impacts, including significant loss of business travel as consultants and deal makers do much more work remotely. It includes the flattening of population growth globally, with the latest projections of peak population as early as 2050 and only as late as 2080 in the latest UN projections. It includes both the massive diversion of potential flight demand to high-speed rail in Asia and to autonomous over night, electric car trips in many parts of the world.

Notably, it includes diversion of very large percentages of shorter flights to battery electric air travel, something which increases until in roughly 2070 I have the optimistic perspective that new battery chemistries will enable transoceanic flights. Even before then, in the late 2030s, silicon chemistries which have started commercializing and improving already have a theoretical peak energy density sufficient for 3,000 kilometer flights, sufficient for the vast majority of within-continent air travel.

Finally, it respects the basic economics of increasing aviation fuel costs. Direct battery electric will be less expensive per passenger mile for fuel and maintenance, and increasing autonomous flight, initially for large cargo and utility unmanned aerial vehicles over low-risk flight paths, will reduce direct pilot labor costs for shorter flights. However, neither of these are going to be available to longer passenger jet flights as cost reduction levers likely until closer to 2050. As such, longer haul aviation will become more expensive, as no jet fuel pathway is cheaper than turning geological hydrocarbons into forward movement while using the atmosphere as an open sewer. The increase in jet fuel costs is something the ICCT’s work respects in principle, but not in practice. They don’t adjust demand downward for increase ticket costs, but leave the 4.5% demand projections alone.

Having done the math on hydrogen and synthetic fuels myself multiple times, I exclude them from the running simply because they won’t be economically competitive. The decline in demand is sufficient that second-generation sustainable aviation biofuels from waste biomass can easily provide the supply for all aviation that doesn’t electrify through 2050. Further, those biofuels divert biomass which would often turn into methane through anaerobic decomposition to much more climate friendly pathways leading to carbon dioxide emissions. All of those supply chains and industrial processes will electrify in my outlook as well, leading to arguably negative carbon, but in my projections carbon-neutral aviation.

There is far more than enough waste biomass for the purpose. I’ve done a survey and analysis of much of the scale of supply and technologies, from stalk cellulosic to food waste to livestock dung, and there are sufficient points in the supply in the supply and waste chains where there is enough biomass that it is convenient for automated collection and processing. I’ve also assessed food competition and it’s more hysteria than reality. We waste 2.5 billion tons of food annually, and the relatively tiny amount of energy crops we grow doesn’t begin to put a dent in that. Food scarcity is an economic, distribution and policy failure, not a biofuels problems.

The good news is that much of the ICCT aviation-related analysis does focus on sustainable aviation biofuels. The bad news is that because they divert no aviation to electrification and have outsized growth projections, they assert in their reports that there is insufficient biomass for the demand. The 2021 report An assessment of the policy options for driving sustainable aviation fuels in the European Union demonstrates these challenges with ICCT analysis. While good, it starts from a bad framing of demand assumptions and ignores the transformation that electrification will bring to aviation.

It’s not like the ICCT’s larger team ignores electrification of aviation entirely. The report Performance Analysis of Regional Electric Aircraft from 2022 is on the subject, but has failings. The first is that it assumes very, very slow improvements to low levels in battery energy density, 300 Wh/kg in 2030 and 500 Wh/kg in 2050. This is amusing simply because CATL released a 500 Wh/kg aviation production battery in 2023, 27 years earlier than ICCT’s timeline. Similarly, there are silicon anode battery chemistries available from four organizations on a couple of continents which are in that energy density range already as well, with theoretical maximums of 5 times that possible by 2040.

Further, while nodding at hybrid models, the ICCT range and passenger capacity analysis ignores them. Obvious models for hybrid airplanes where reserve and divert are managed by SAF generators are already being built and demonstrated. Ampaire has just completed a 12 hour demonstration flight covering 2,220 kilometers with its hybrid drive train. I’ve spoken to aerospace engineers on multiple continents about battery electric and hybrid aerospace models and am comfortable that current technologies allow much longer distances and passenger numbers than the ICCT report concludes.

Further, having been on the advisory board of a battery electrochemistry firm and spoken to electrochemists and battery experts globally, I’m comfortable that the ICCT is simply wrong regarding its published opinions on the potential for both pure battery electric and hybrid models. Right now up to 100 passenger turboprop flights of 300 kilometers with divert and reserve provided by SAF biofuel hybrid models are entirely technically possible. By 2040, my projection is 3,000 kilometers with silicon chemistries. And remember, every battery replacement for every plane will increase range in the coming decades.

So the ICCT is effectively dismissive of battery electric aviation, thinks that aviation demand is going to be vastly higher than it will be even if they just used their own projections in the simplest of guns and butter economic models, and thinks as a result that there isn’t sufficient waste biomass for the remaining fuels. They’ve painted themselves into a corner, and here’s where hydrogen and synthetic fuels re-enter the equation.

Clearly if you establish the conditions that mean that there is insufficient energy from other sources, then you have to find ways to justify deeply expensive and wasteful hydrogen and synthetic fuel pathways. That’s what likely led to the deeply wrong headed report on e-kerosene with its $1.6 per kilogram hydrogen. That very low cost of the primary cost driver is required for any of this to make any sense.

And it’s not alone. Obviously if they’ve dismissed batteries and the sufficiency of biofuels, that means they probably have to spend a lot of time on direct use of hydrogen in aviation. And they do.

Let’s start with the basics. Aircraft that use hydrogen directly aren’t going to be a thing, as I explained at length after sitting on a master’s thesis panel on the subject of integrating hydrogen aviation into airports earlier this year, and it’s even more sure than for ground transportation where every niche is already provably filled with batteries, grid-ties or hybrids of the two. Hydrogen will always be more expensive than SAF biofuels, so it won’t be able to compete. Gaseous hydrogen has far too low an energy density to be more than a curiousity.

Liquid hydrogen requires putting globe-shaped highly insulated tanks full of much more expensive cryogenic hydrogen at 20° above absolute zero inside the fuselage with passengers. Hydrogen inside the fuselage, whether gaseous or liquid, will have a strong tendency to leak as a gas with an explosive range of 4% to 74% of internal cabin air and a spark point in the range of basic electrical appliances. Further, it is highly reactive with electronics, requiring completely different electronics. The combination of extreme temperature ranges and within cabin gas means that liquid hydrogen isn’t certifiable for civilian aviation. There’s no way to make anything except flying death traps and civil aviation doesn’t allow those. Boil off of hydrogen in small tanks within planes means that it will lose significant range with only 1-2 hour waits on runways or circling. The former means that relatively normal delays will require returning to the terminal, recalculating fuel requirements, refueling and leaving again. Every minute of divert flying eats away at reserve significantly as well.

But it gets worse. Aviation fuel is currently mostly stored in the wings of airplanes as they are suspended by the air and don’t impact maximum gross take off weight, a fundamental flight fuel calculation. With heavy tanks and fuel inside the fuselage, range plummets radically.

And it gets worse again. If the tanks are in a narrow body plane at the back of the plane — the only possibly configuration — and one requiring extending the airframe length for any reasonable ratio of fuel to passengers, then the balance of aircraft is radically altered. The fuel weight is well behind the wings instead of balanced through the center of mass. That’s entirely manageable for takeoff with brand new aircraft, but the Boeing 737 Max debacle makes it clear that it’s not manageable just by tweaking existing airframes and letting avionics manage it.

But it’s entirely not manageable over the course of the flight. Aircraft balance around center of gravity is a carefully managed process, with recertification required for things as simple as replacing cargo hold doors. Luggage distribution and passenger distribution are carefully assessed. Fuel is managed to maintain the balance.

All that goes out the window when hydrogen is consumed during flight. Hundreds or thousands of kilograms of mass will disappear from the furthest part of the plane behind the wings, at the point where the plane’s center of gravity will be most impacted by its removal. Liquid hydrogen has 2.8 times the energy density by mass as Jet A, but even in the smallest aircraft they model, 1,190 kilograms of mass is for the hydrogen, and that’s going to disappear from the tail over the course of the flight. For anyone who hasn’t flown in a sparsely passengered turboprop recently, they put equal numbers of passengers at the front and rear of aircraft for balance around the center of gravity, and big humans weigh 100 kilograms. Having a dozen husky men disappear from the back of a 72-passenger plane while no one disappears from the front would cause the plane to go into a nosedive.

For the biggest aircraft they model, it’s 5,050 kilograms, a full five tons, the weight of a full grown elephant.

Proponents of hydrogen aircraft never do mean gross takeoff weight calculations and they never do center of gravity transformation calculations in flight. Further, they never bother to look at certification requirements for civilian aircraft and determine what it would take to certify 20° Kelvin hydrogen next to human beings inside a pressurized tube traveling through the air.

Certainly the ICCT whitepaper Performance Analysis of Evolutionary Hydrogen-powered Aircraft from 2022 is silent on all three points. Should it have been? Of course not. A quick assessment of the backgrounds of the primary authors indicates that one is an actual aerospace engineer and one is a civil engineer who has been involved in assessing decarbonizing aviation since 2008. These clearly obvious red flags and operational nightmares are within their academic and intellectual scope to recognize, yet the report is completely silent on them even as acknowledged risks. Certification gets a slight mention in a footnote related to engines, as if hydrogen inside the fuselage and passenger safety aren’t worth considering.

Bizarrely, that paper also claims that green hydrogen would be cheaper than blue hydrogen. While the latter if made from natural gas will never be cheaper than hydrogen without carbon capture, there is no credible analysis that indicates green hydrogen will be cheaper, just much more environmentally benign. The green H2 costs are from the same 2022 ICCT paper that deeply lowballed green hydrogen by giving it subsidies, dirt cheap electricity and no balance of plant, so there is a chaotic attractor of hydrogen cost failures. To be clear, the 2022 paper had lots of nuance about what was and wasn’t within scope that referencing papers clearly ignored.

The more recent 2023 paper Performance Analysis of Fuel Cell Retrofit by one of the two authors of the hydrogen aviation paper just discussed has exactly the same problems. Zero calculation of maximum gross takeoff weight implications of fuel (and fuel cells and heavy tanks) inside the fuselage. Zero assessment of shifts in center of gravity as hydrogen is consumed. Zero attention to certification requirements.

Having painted themselves into a corner which requires hydrogen and e-fuels for decarbonization, the ICCT created an organizational environment where they had to find some way to cost justify hydrogen and e-fuels. That results in unnatural acts like the bad trucking total cost of ownership study, the barely and badly costed focus on liquid hydrogen for shipping, and the entire range of their recent aviation focus. This led a couple of ICCT researchers who in 2018 had basically restated the obvious, that hydrogen and derivative fuels were too expensive to conceivably be alternatives, to publish in 2022 a flawed assessment which said that hydrogen would be cost effective under deeply unrealistic conditions.

Then other ICCT researchers, also working within this bubble where hydrogen and its derivatives were clearly essential, cherry picked the cheapest, best case, most under loaded hydrogen costs from their papers and add other ways hydrogen could be even cheaper.

It’s been a slippery slope for the ICCT and its staff. Over five years they’ve devolved from a reasonably rigorous research group to one grasping at hydrogen straws because they got a bunch of fundamental stuff wrong. They are clearly predisposed to molecules for energy across the organization. They are clearly predisposed to massive growth of transportation passenger miles despite very obvious reasons why that’s not realistic and why the projections are unrealistic. They don’t get batteries and electrification. And as a result they vastly overstate molecules for energy requirements and then find that biofuels from waste biomass are insufficient. This results in them requiring hydrogen and synthetic fuels manufactured from it for transportation fuels despite their organization understanding historically that they were absurdly and uneconomically expensive. And then they contort themselves to find ways to justify hydrogen and their derivatives.

Until they confront this cognitive trap and overcome it, the likelihood than anything that they publish is worth looking at is very low. Also, the organizations funding the ICCT aren’t achieving the goals that they want, rapid decarbonization of transportation. Quite the opposite. The ICCT has stumbled backward into being a delayer of decarbonization in land, sea and air transportation.

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A few words on credentials, authority and bias.

It’s pretty easy to find reasons to consider the ICCT’s publications more credible than mine, and to consider my critique of the ICCT’s publications as slight. That would probably be a mistake, but it’s an understandable and forgivable one. Let’s explore this a bit.

On credentials, the ICCT researchers all have PhDs as far as I can tell, even if not directly relevant to their ICCT publications. I have a couple of years of undergraduate science and math, a computers and business degree and a bachelor of literature. It’s easy to assume from that their publications and opinions are more credible. I do the same credibility calculus. That said, none of the analyses I do or the critiques I offer require PhD levels of science or math. Everything I point out is something that a first year science and math or even grade 12 science and math student could figure out. This isn’t rocket science. It’s basic stuff. No one who wants to check the numbers or science requires a PhD to rework the basics. A PhD extends human knowledge, but none of the ICCT’s research extends human knowledge, it just analyses what is known. At best it’s Masters level work. Frankly, a disciplined person with a 100 IQ and the internet could do what I do, albeit likely more slowly. Does this mean I am right and they are wrong? Of course not, but it does mean that their credentials are only somewhat relevant.

On authority, the researchers have a bigger place to stand and a lever longer than mine. They are members of a Washington-headquartered, globally officed think tank that’s been around since 2001. I’m one guy with my one-person think tank and consultancy. They write reports with multiple authors and multiple reviewers. I write articles that get retracted or corrected when I make embarrassing mistakes. They have decent budgets for formatting and graphics. I use Google Sheets charts and generative AI image tools. It’s quite easy and not wrong at all to assume that ICCT reports are more authoritative than my work. I wouldn’t begin to disagree. If readers choose to lean on ICCT material instead of my assessments and critiques, that’s completely reasonable. That doesn’t make them right. The appeal to false authority might be a logical fallacy in either direction.

On bias, neither the ICCT or I have a venal predisposition to fossil fuels and hence hydrogen for energy for those reasons. We share a predisposition away from fossil fuels and for climate action. But the ICCT researchers are mostly long-term transportation analysts, and that leads to, based on my focused observations, a predisposition toward molecules for energy. In general, transportation types aren’t electrochemistry or battery types. They spent their formative academic and professional careers in a space where molecules are burned for energy and have a bias toward molecules as a result.

And the ICCT researchers are in a bit of an organizational bubble. They reference each others’ work constantly, likely as a requirement pushed upon them by guidance and review. It’s harder to guard against group think or cherry picking extensions to unnatural and unsupportable positions like the ones that they have published on trucking, shipping and aviation. 

Does this mean that my independence is necessarily less biased? Of course not. There are innumerable independent cranks out there who make it clear that iconoclastic independence isn’t remotely a precursor to rational, empirical analysis. And it doesn’t make me immune to the group think which has clearly caught the ICCT in its web. I have my own networks of people who agree with me, even if the ties are more ephemeral. I’m as subject to the challenges of confirmation bias and bubbles, just a little less so than than the ICCT staff.

And I’m subject to specific criticisms related to bias. I am or have been on the advisory boards of two electrified aviation start ups. I’ve been a strategic advisor to a battery electrochemistry startup. It’s easy to point at those details and say I’m selling a perspective. Except, of course, that I came to my conclusions on batteries and aviation before taking those positions. Those positions were offered to me by deep professionals including electrochemistry PhDs because I’d done and published the hard analysis work from the fundamentals of science, math and economics, not because I was willing to pitch their perspective. I’ve turned down far more advisory roles than I’ve accepted. Does this make me a perfect and virtuous Spock-like creature? Of course not. It just counter balances an obvious criticism.

The last point on bias is related to framing. The researchers at ICCT have focus areas in transportation. Some of them are (unnecessarily) focused on the cost of hydrogen in its various forms. Others are focused on maritime shipping. Others on trucking. Others on aviation. They have a framing problem which means that they have a tendency to compare a subset of potential options and depend on others for the math related to hydrogen. It’s somewhat easier for them to assume other people’s numbers are correct because they haven’t done the work themselves.

By comparison, I have a frame which includes all of the above, including calculation of hydrogen manufacturing, distribution, compression and liquification. That means I include at least more of the options, but it does mean that when it comes to detailed analyses and simulation of narrow lanes within the space, I’m likely to miss stuff. Trying to know all the basics means I am likely to miss salient details. I’ve worked through a lot of that but don’t pretend to know everything.

Both frames, narrow and broad, are valid. Both have strengths. In this case, I think the weaknesses of the ICCT researchers specialization has created significant problems. But they could equally argue that my lack of depth on specific models that they employ leads to me being incorrect. That multiple global hydrogen and transportation experts seem to agree with me from my perspective does not mean my perspective on their agreement is accurate.

All of that said, the funders, Board and executive of the ICCT should be considering seriously the data, logic and supporting material I’ve brought together in my critique, along with the publicly stated support for it from global thought leaders. If I’m correct in my critique, this is an existential threat for the organization and a failure to achieve its objectives.