Carbon-neutral jetfuel

 

From RenewEconomy

British synthetic fuels developer Zero Petroleum is exploring the possibility of building a low-carbon sustainable aviation fuel production facility in the South Australian city of Whyalla, in collaboration with Qantas Airways.

The feasibility study is expected to take six months and will evaluate the technical, economic, and environmental viability of a facility which would be capable of producing up to 10 million litres of synthetic aviation fuel, gasoline, and diesel each year.

It will seek to tap into the state’s huge wind and solar resources – which already account for around 75 per cent of annual demand, and which are expected to reach 100 per cent net renewables by 2027 – and its emerging green hydrogen production facilities in the same city.

Zero Petroleum was founded in 2020 by former F1 racing engineer and executive Paddy Lowe and subject expert Nilay Shah, a professor of process systems engineering at Imperial College London.

Their company has developed and manufactures whole-blend and 100% fossil free synthetic fuels – including gasoline, diesel, and jet fuel – through a process utilising direct air capture (DAC) carbon dioxide and hydrogen from water electrolysis, all powered by renewable energy.

This is designed to create fuels which are intended for use in an array of hard-to-abate sectors – including the aviation industry and motor racing series such as Formula 1.

DAC is the process whereby CO2 is extracted from the atmosphere.  DAC is expensive, costing over $1000/tonne, although as its usage increases, and learning curve effects strengthen, it is likely to fall in cost.   DAC may be the right way to go for removing CO2 from the atmosphere, but it is prolly not the best way to make synthetic hydrocarbons.  The process used by Prometheus Fuels will (if it works) be much cheaper.  We are just at the beginning of learning how to make carbon-neutral fuels, so it makes sense to try several technological possibilities, to see which works best and which is the cheapest.  We shall see which process wins out.

The hydrogen furphy

I've been suspicious about the hydrogen mania for a while now.   Michael Liebreich does a much better demolition job than I could.   But his recommendation to use green ammonia, made from green hydrogen, for long-term storage in electricity generation is very interesting.   And I don't share his doubts about using e-fuels for jets.  If e-fuels cost twice as much as jetfuel, so be it.  We survived without intercontinental jet flights before, and we could again.

[From BNEF]

By Michael Liebreich

Senior Contributor
BloombergNEF

Injecting some reality

Two years ago, BloombergNEF published my two-part primer on hydrogen, Separating Hype from Hydrogen. On the supply side, I was optimistic: green hydrogen (produced from renewable energy) would over time become cheaper than blue hydrogen (produced from natural gas but with carbon captured) and eventually cheaper than gray hydrogen (produced form natural gas without carbon capture).

On the demand side I was more skeptical. While clean hydrogen will be needed to decarbonize a number of use cases in industry, and perhaps for long-duration storage, I found it hard to identify any role for it in applications like land transportation or space heating. Since then, as I have done more work on industrial heat, I have even come to believe it has a limited role even there.

If my intention at the time was to inject some reality into discussions about hydrogen, I clearly failed. Rhetoric around hydrogen has become ever more overblown.

According to lobbying group the Hydrogen Council, citing a series of reports commissioned from McKinsey over the past three years, hydrogen can be expected to contribute more than 20 percent of emissions reductions needed for the world to reach net-zero emissions – a figure repeated by politicians and journalists seemingly without the slightest critical examination.

German Chancellor Olaf Scholz has called hydrogen “the gas of the future” and promised “a huge boom.” Japan’s Prime Minister Fumio Kishida has declared that “shifting to and developing a hydrogen society is critical for achieving decarbonization.” Frans Timmermans, the EU Executive Vice-President for the European Green Deal believes that “hydrogen rocks.” Jacob Rees Mogg, briefly UK Secretary of State for Energy this year, called hydrogen “the silver bullet”.

Public money is starting to flow. The EU has approved the first 13 billion euros ($13.7 billion) of the 430 billion euros ($450 billion) promised under its 2020 Hydrogen Strategy and is now working to launch a “Hydrogen Bank”. The US Inflation Reduction Act (IRA) provides a ten-year tax rebate per kilogram of green hydrogen worth $3, which will soon be more than the production cost itself. Free hydrogen anyone?

Of supreme import

In October this year the Hydrogen Council and McKinsey released another report entitled Global Hydrogen Flows, predicting long-distance transport of 400 million tonnes of clean hydrogen and its derivatives (calculated on a hydrogen-content basis) by 2050, out of total global production of 660 million tonnes of hydrogen. It is worth bearing in mind that today, 94 million tonnes of hydrogen are used annually, virtually all of it made from fossil fuels, creating 2.3% of global emissions. The vast bulk of today’s hydrogen never leaves the compound on which it is made, let alone cross an international border.

The idea of hydrogen imports as a way of decarbonizing major industrialized economies is enormously seductive – so much so that Germany and Japan have made it central to their decarbonization strategies. Here’s Japanese PM Kishida again: “Japan aims to commercialize an international hydrogen supply chain by producing hydrogen in bulk at low cost in countries blessed with bountiful renewable energy resources coupled with marine transport infrastructure.”

Chancellor Scholz is promoting hydrogen imports not just as a way of decarbonizing the German economy, but as a replacement for Russian gas. In August he and Canadian Prime Minister Justin Trudeau flew to Newfoundland and Labrador to sign an agreement to “create a transatlantic supply chain for hydrogen well before 2030, with first deliveries aiming for 2025”. As I write this, German Economy Minister Robert Habeck is on a five-day trip to Namibia and South Africa to secure hydrogen supplies.

The problem with this vision of large-scale imports of hydrogen is that the physics of hydrogen is unlikely to play ball.

The unbearable lightness of hydrogen

In February this year, Kawasaki Heavy Industries’ Suiso Frontier arrived in Kobe, Japan carrying the world’s first ever cargo of liquid hydrogen from Australia. Did this momentous occasion herald the start of a brave new world of trade in liquid hydrogen, as the press coverage suggested? In a word, no.

Set aside the A$500 million ($334 million) cost of the project; set aside the fact that most of the hydrogen on board the Suiso Frontier was made from coal; and set aside the fire that broke out on board while loading. The 1,250 cubic metres of hydrogen carried by the Suiso Frontier contained just 0.2% of the energy content of a single large LNG carrier. Okay, the first ever LNG cargo, carried 63 years ago from the Calcasieu River on the Louisiana Gulf to the UK, consisted of a similarly picayune 2,475 tonnes. Surely liquid hydrogen can be scaled up in the same way as LNG has been? Kawasaki Heavy Industries, builder of the Suiso Frontier claims it has already lined up the first order for a much larger, 160,000 m3 carrier from Nippon Kaiji Kyokai.

This is where the physics of liquid hydrogen step in. Although the scaled-up vessel would carry 60% of the volume of an LNG Q-Max, it would carry only 22% of the energy.

Hydrogen has very good gravimetric energy density – the amount of energy carried per unit weight. On this measure, hydrogen beats diesel, petrol and jetfuel by a factor of around three, and LNG by a factor of 2.7 – which is why it makes a great rocket fuel. However, it has very poor volumetric energy density – the amount of energy carried per unit volume. It’s worth remembering that while a cubic meter of water weighs 1,000 kilograms; a cubic meter of hydrogen weighs only 71 kilograms.

On a volumetric basis, hydrogen’s energy density is a quarter that of jet fuel, and only 40% of that of LNG. Since ships are volume constrained (think Suez Canal, Panama Canal, etc.), this inevitably means more trips. Even if Kawasaki Heavy Industries was to scale its hydrogen carrier to the same size as a Q-Max, it would need to make 2.5 deliveries to carry the same amount of energy as one cargo of LNG. You don’t need to know anything at all about shipping to know that 2.5 times the trips are going to cost you 2.5 times as much.

But this is only the start. A liquid hydrogen carrier will inevitably be more expensive than an LNG carrier. Its load will be at -253C instead of -162C, and all pipes, valves, pumps and tanks have to resist hydrogen embrittlement. And because liquid hydrogen is both colder and lighter than LNG, the liquid hydrogen ship would have up to nine times more boil-off en route (these ships let some of the load boil off as heat enters the tanks, and then use that as fuel for their engines), unless you add either much more insulation or a complex cryogenic recycling system.

Overall, you would be wise to assume that the seaborne segment of your hydrogen trade will cost around four times the cost of LNG per unit energy.

It’s the physics, stupid

But that only deals with the seaborne segment. We still have to talk about liquefaction and regasification.

Liquefying hydrogen is a is a hugely energy-hungry process, made complex by the quirks of hydrogen physics – things like its negative Joule-Thomson Effect (unlike most gases, hydrogen gets warm when it expands and cold when compressed) and ortho-para isomer conversion (without which liquid hydrogen re-evaporates, irrespective of insulation). Liquefaction of hydrogen currently consumes 30-40% of its energy content, versus no more than 10% for LNG. Ways to improve this are being researched, but nothing can change the fact that liquefying hydrogen is, quite simply, a bear.

As for regasification, again the plants will be more expensive than for LNG. They need to operate at lower temperatures; all valves, pumps, pipes and tanks have to resist embrittlement; and compressors have to be of larger capacity because pressurizing hydrogen gas requires more work than pressurizing natural gas. European politicians, scrambling to build new terminals to receive LNG in replacement of Russian gas, are suggesting that these terminals will be repurposed to receive hydrogen or its derivatives. This is nonsense. You can re-use the docks and infrastructure, and any distribution pipelines can be upgraded, but 70% of everything else has to be scrapped.

In summary, while LNG approximately doubles the cost of gas delivered by pipeline, shipping liquid hydrogen will cost four to six times more than LNG. In other words, you can’t power an economy on imported liquid hydrogen, and that is not because of things that can be fixed – scale, technology, cost of capital and so on – but because of the underlying physics: volumetric density, liquefaction temperature and interactions with other materials.

It’s a gas, gas, gas!

If importing hydrogen in liquid form is out, what about importing hydrogen as a gas?

Here, things look much better. Gaseous hydrogen is already transported by pipeline – all the pipes, pumps, valves and tanks need to be appropriately engineered, but the economics are not terrible. Just as well, given the volume of hydrogen we are going to need at industrial “hydrogen hubs” for industrial uses and to provide long-duration back-up power.

Just replacing the current production of gray and black hydrogen would create demand for 94 million tonnes of clean hydrogen. Pipeline imports are well-placed to meet a decent proportion of this.

There is, however, a caveat. The longest natural gas pipeline in the world (excluding side branches) is Brazil’s National Unification Gas Pipeline (GASUN), just under 5,000 kilometers long. In their report on hydrogen trade, McKinsey and the Hydrogen Council predict 40 hydrogen “trade routes” connecting the globe. Those serving Europe by pipeline from Norway, North Africa and the Gulf are certainly feasible (the one from Russia is clearly off the cards for decades). However, none of the longer trade routes linking the US West Coast with Asia, the US East Coast with Europe, or the Gulf, Africa or Australia with Asia are likely to carry a single cubic meter of gaseous hydrogen.

There are a few companies proposing to carry compressed hydrogen gas by ship. This would allow them to avoid the cost and complexity of liquefaction but would expose them to the same problems of lower volumetric energy density, only more so. Provaris Energy has designed a ship carrying hydrogen gas at 250 bar. But this translates to just 25 kilograms of hydrogen per cubic meter – just over a third of the very poor volumetric density of liquid hydrogen. Scaled up to the size of a Q-Max, their ship would carry around one seventh of the energy. Seven ships to do the work of one, you can imagine what that does to costs.

There may be some niche applications for shipping gaseous hydrogen, for instance moving stranded supplies between islands, but it is not going to happen in more than homeopathic quantities.

The exotics

There are other ways of transporting hydrogen beyond liquid and gas. We’ll get on to derivatives of hydrogen in a moment, but first I want to deal with the exotics – liquid organic hydrogen carriers (LOHCs) and metal hydrides. Here the goal is to load hydrogen into a chemical or metal carrier, which allows it to be transported at ambient temperatures and pressures. On arrival the hydrogen is released and the carrier returned to the point of origin.

One promising LOHC is benzyl toluene, being marketed as a solution for hydrogen shipping by a company called Hydrogenious. But again it has a volumetric density problem. One cubic meter of benzyl toluene can only be loaded with 54 kilograms of hydrogen – which means four times as many trips for each energy cargo as you would have with LNG. In addition, loading hydrogen into the organic solvent is an exothermic process, generating heat where you don’t need it, and then you need to add energy at 300C at the arrival location to extract it – using up around 30% of the delivered energy.

That’s not to say LOHCs are not interesting: they could perhaps find a role in long-duration stationary storage – not everywhere has the salt caverns or depleted gas fields required to store gaseous hydrogen, but any tanker farm would be able to handle benzyl toluene and there may be options to store and reapply the process heat between cycles. There may even be a modest import market for LOHCs, to replenish long-duration storage tanks.

Metal hydrides offer the hope of transporting up to twice as much fuel per cubic meter as liquid hydrogen – but each family of hydrides studied so far has shown disadvantages: cost, gravimetric density, time to charge, absorptive capacity, heat required to release the hydrogen and so on. It would be a brave investor who thought we were going to move hydrogen at scale this way, when 50 years of research has not yielded as single commercial application.

First derivatives

Next up, hydrogen derivatives – e-methane, e-methanol. These are certainly easier to transport – drop-in replacements for their fossil equivalents. Their problem is high production cost. For each of them you need a source of clean hydrogen – whether blue, green, pink or red (from nuclear power, whichever color code you use) or whatever – plus a source of carbon nearby, and then you need to combine them into molecules of varying degrees of complexity.

The cheapest source of carbon would be captured from the combustion of fossil fuels – but that would make no sense as it would not be compatible with net zero. The only thing that could possibly make sense would be to use direct air capture (DAC) or secure carbon from a bio-based source, so that when it is burned it just returns to the atmosphere.

A bit of systems thinking, however, shows that even this makes no sense. Take e-methane. By the time you have gone to the cost of securing your carbon, why not just sequester it, instead of incurring further costs in producing hydrogen and combining them into your derivative. You could then just deliver plain old fossil gas to the importing country – along with a carbon credit if needed. That would be identical from a climate perspective and vastly cheaper.

Methanol can and must be made in future using clean hydrogen. Some of it will be made where hydrogen is cheap and exported, but only for use cases where it will be consumed as methanol. In 2022, global production of methanol was 110 million tonnes – but adjusting for molar weights, that is equivalent to just 14 million tonnes of hydrogen. Should demand double and a third of that get traded internationally, only a 9 million-tonne import market by hydrogen mass would be created. That barely scratches the surface of the Hydrogen Council’s 400 million tonnes.

E-methanol also represents a potential pathway to decarbonize shipping – but ammonia and waste-based biofuels both look like being cheaper. Even using nuclear power for the world’s largest ships would most likely be cheaper than e-methanol. Global shipping fuel demand today is around 300 million tonnes per year; let’s suppose, optimistically, that demand increases by 50% by 2050, that 20% is replaced by methanol, and a third of that methanol is traded internationally. Once you adjust for the molar mass and energy content of methanol, that would only create annual demand for another 8 million tonnes of hydrogen imports.

e-Fuels

Some continue to promote e-fuels as the solution for land transportation, particularly in Germany and Japan. They point to the fact such fuels require no changes in consumer behavior, highlight the millions of jobs that depend on the internal combustion engine and claim that scrapping 1.4 billion internal combustion vehicles on the world’s roads would be unaffordable.

Their arguments have no merit. First, those 1.4 billion vehicles will be scrapped anyway before whichever year countries select for net zero. In most cases, electric vehicles are already competitive on a total-cost-of-ownership basis with petrol and diesel. E-fuels, by contrast, will still be three to five times as expensive in 2050, driven by their production complexity and the efficiency losses at each production stage. Yes, Porsche is building a pilot project in Chile to produce e-fuels, but theirs is not exactly a cost-conscious customer base.

The fact is that those jobs associated with internal combustion engine manufacturing will be disappearing anyway, the only question is whether they are lost to other technologies or to China. As for behavioral change, most EV users like the fact that they can charge anywhere, rather than having to visit a gas station every week.

Flights of fancy

Time for a deep dive into hydrogen’s potential use in aviation. Airbus has said that it “considers hydrogen to be an important technology pathway to achieve our ambition of bringing a zero-emission commercial aircraft to market by 2035,” and this month, Rolls-Royce and EasyJet made the news by testing a turboprop engine on pure hydrogen.

It turns out that running an aircraft engine on hydrogen is not the difficult bit – the Soviet Union did it back in 1988, not on a test bench but in the air. The real problems are caused, once again, by the physics of hydrogen.

With just 25% of the energy density of kerosene, replacing the maximum take-off fuel load for a long-haul aircraft would require more space than the entire swept volume of its fuselage – a non-starter. For short-haul flights, the focus of Easyjet’s interest, the fuel tank would take up around a third of the fuselage. That means ticket prices 50% higher than now, even before paying for the higher costs of the plane, the cost of the liquid hydrogen, and cost of its ground handling equipment. In total, expect a doubling or tripling of prices.

The real show-stopper, however, is getting the fuel to the airport. Liquid hydrogen transfer lines exist, but there is no way to keep miles of pipeline at -253C and handle the safety issues of any potential leaks. That leaves road tankers or gas pipelines.

Let’s do a thought experiment: try to replace all 20,000 tonnes of jet fuel delivered daily to Heathrow airport with 7,200 tonnes of liquid hydrogen. By tanker truck, that would mean 2,300 daily movements of liquid hydrogen in West London. The safety and traffic implications don’t bear thinking about. Now the only option is to bring the hydrogen in by gas pipeline, and liquefy it on site. But that would require 2.7GW of electrical power, according to engineer and Oxford University ammonia expert Dr. Mike Mason – approximately the output of a new nuclear power station the size of Hinkley C, plus a lot of pylons. And then you need to dump enough heat to raise the temperature of the Thames by 18 degrees C.

The bottom line is that liquid hydrogen could perhaps end up powering a few executive jets – startup ZeroAvia certainly hopes so – but not aviation as we know it. The only substantial role for hydrogen in aviation would be through the production of e-fuels. These are certainly technically feasible – UK company Zero Petroleum has already made some – but they look like being at least twice as expensive as sustainable aviation fuels (SAF) based on agricultural or forestry waste.

If potential volumes of SAF are limited by feedstock availability, then there is a market opportunity for hydrogen in aviation fuels, if not, there isn’t. Global aviation fuel demand was around 300 million tonnes in 2019, which translates to 46 million tonnes on a hydrogen mass basis. If demand grows by 50%, 25% is met by e-jetfuel and one third of that is shipped internationally, that only generates 6 million tonnes of traded hydrogen.

Moan, moan, ammonia

That brings us, finally, to ammonia – the last option for those hoping to develop substantial long-distance hydrogen imports.

Around 190 million tonnes of ammonia are produced each year, mainly for fertilizer and as a chemical feedstock, almost all of it from fossil feedstock. Around 10 percent of current production is already traded internationally but this only comes to around three million tonnes by hydrogen mass.

Switching to clean ammonia for fertilizer production will without doubt drive a big increase in traded hydrogen. Where there are pipelines, hydrogen can be made where renewable power is cheap and imported in place of natural gas and used to make ammonia at the destination. Where there are no pipelines, green ammonia or finished fertilizer will be produced and shipped instead.

Supposing the fertilizer market grows by half by 2050, all of it goes low-carbon and a third of it ends up being shipped internationally, that would increase ammonia trading from 18 to 95 million tonnes per year – a lot of ammonia. This will be a relief for those investing in ammonia projects in Chile, Canada, Namibia and South Africa: their output may not find much use in the energy sector, but at least they should have access to a very substantial market. It is, however, only 17 million tonnes on a hydrogen mass basis.

Back to shipping fuels. Since ammonia will be cheaper than methanol, as discussed, let’s be optimistic and say half of the volumes described above are replaced with ammonia, and a third of it is traded internationally. That would drive an additional 25 million tonnes of demand by hydrogen mass.

Japan’s big bet

Japan is betting that imported ammonia will be used to generate power. Its national decarbonization plan is based on retaining its coal-fired power stations, but fueling them with increasing proportions of ammonia – first 20%, then 50%, then 100% by 2050. So confident is it – and so keen to keep selling its technology internationally – that it is encouraging Vietnam and other South-East Asian countries to keep building coal-fired power stations. Will the bet pay off?

Let’s look first at ammonia made from green hydrogen. That means generating wind and solar power; using it to produce hydrogen (80% efficiency); making ammonia via the Haber-Bosch process (70% efficiency); liquefying it (90% efficiency); shipping it (90% efficiency); and burning it to generate power (45% efficiency). Your end-to-end efficiency will be an astonishingly poor 20%. Although it might be possible to improve the efficiency of each of stage, the tyranny of multiple process steps means your end-to-end efficiency is hard to budge.

What 20% end-to-end efficiency means is that the resulting power will cost five times as much as the original power – and that is before accounting for capital invested in all those process stages and maintenance. In addition, combustion of ammonia produces nitrous oxides – hazardous to health and powerful greenhouse gases in their own right.

Now, ammonia from blue hydrogen. You eliminate the electrolysis stage, so your end-to-end efficiency is a little higher at 26%, but you have the extra cost of carbon capture and sequestration, so the resulting power cost is going to be about the same. The real question, however, is why bother? Why not just ship the natural gas to Japan instead of ammonia – LNG has 1.7 times the volumetric energy density of ammonia, so you need fewer cargoes. Then you capture the CO2 at the other end, and either sequester or send it back to the point of origin on the same ships. You have the same climate impact, approximately the same cost of carbon capture and sequestration, but significantly greater efficiency and lower shipping costs.

The bottom line for ammonia as a fuel for power generation, whether co-fired or pure, is that no economy can be internationally competitive based on the resulting power prices. My estimates are in line with the more detailed modelling work undertaken by BloombergNEF: BloombergNEF found that 100% ammonia-fired power in Japan would cost around $260 per megawatt-hour in 2030 and $200 by 2050 – around double the cost of renewable energy.

The fact that Japan could generate large amounts of renewable energy – in particular, offshore wind – at much lower cost points to the role that clean ammonia could in fact play in the country’s power system: providing back-up. Bill Gates likes to quote Vaclav Smil on the three-day cyclones that hit Tokyo almost every year – which would shut down renewable generation and leave it short of 22GW of power. He laughs at the idea that batteries could fill the resulting gap, and he is correct to do so. However, the gap is only 1,600 GWh, which could be generated from a million cubic meters of ammonia – an amount that could be brought in on just four Q-Max-sized carriers.

So, while basing Japan’s economy on electricity generated from imported ammonia is an economic non-starter, storing a few million tonnes of ammonia and using it for long-duration storage looks a lot more realistic.

Conclusions and implications

This has been a long journey and we have covered a lot of ground. I want to leave you with a few conclusions by way of summary.

The only way to move hydrogen economically is as a gas, by pipeline. Forget liquid hydrogen: it will struggle to find any role in the future energy or transport systems because of its poor volumetric energy density and difficulties with handling. It will have no role at all as a traded commodity.

Ammonia will be traded and transported, primarily for use in fertilizer production, plus as a shipping fuel. It will not be imported to power bulk power generation, but will be imported and stored to deliver long-duration storage. Some LOHC might also be imported, but only where it is stored for resilience purposes.

Clean methanol will be made near to sources of cheap clean hydrogen and some of it will be shipped around the world for use as a chemical feedstock. E-fuels – whether methanol, petrol, diesel or kerosene equivalents – will not be shipped around the world in meaningful volumes because their cost will severely limit their uptake, with the possible exception of aviation.

Totting up the various future hydrogen trade flows covered here, it is clear that the Hydrogen Council/McKinsey figures of 660 million tonnes of clean hydrogen production and 400 million tonnes of long-distance transportation are out by a factor of at least three. In addition, given that China and India have only pledged net zero by 2060 and 2070 respectively, such flows that do materialize will take decades beyond 2050.

The implications reach far beyond the question of international trade in hydrogen and its derivatives. The prohibitive cost of long-distance imports means that energy-intensive industries will inevitably migrate to regions with cheap clean energy. It is inconceivable for any country to import iron ore from Australia or Brazil, hydrogen from Australia, the Gulf, Canada or Africa, and make steel at a globally competitive cost. Magical thinking will be no defense against de-industrialization.

Finally, it is worth noting that none of this calls into question the fact that clean hydrogen will be required to decarbonize certain sectors, which will eventually create more than 100 million tonnes per year of demand. Just as railway mania left the world with railways, electricity mania left the world with power networks, and the dot-com bubble left the world with broadband fiber, so hydrogen mania will leave the world with a lot of clean hydrogen.

The worry is that, along the way, we are going to waste huge amounts of money on the wrong use cases for hydrogen and the wrong infrastructure in the wrong places. Worse than wasting money, we will also be wasting time – and that is the one thing we don’t have. Let’s be smart.

Selah.

Michael Liebreich is the founder and senior contributor to BloombergNEF. He is also the CEO and chair of Liebreich Associates, founding managing partner of EcoPragma Capital and an advisor to the U.K. Board of Trade.

Source: BNEF

 

Prometheus Fuels -- petrol from water, air and electricity

Source: Prometheus Fuels

I talked about this nearly three years ago. Today, I checked back to see how this fascinating startup was going. Of course, it's all taken much longer than they were forecasting then. All the same, there seems to have been clear progress. I've taken the text below from a piece written by the founder and CEO of Prometheus Fuels.

Written by Rob McGinnis, Founder and CEO, Prometheus Fuels


As you know, Prometheus converts renewable electricity from solar and wind power into zero net carbon gasoline, diesel, and jet e-fuels (short for “electro-fuels”) that compete with fossil fuels on price. What some readers may not know is that the process we use to do this is new, is only recently possible, and is unlike anything that anyone else is doing to make synthetic fuels today. It is because of this new process that we are the only company making e-fuels that can compete with fossil fuels without new laws or subsidies — our fuels can compete simply by being better and costing less than the fossil fuels they will replace. This is a truly exciting breakthrough in our ability to solve some of the world’s most intractable problems, like climate change, energy security, and the need for increased energy-driven prosperity. But as often happens with breakthroughs of this magnitude, our process has provoked some dramatic responses - It sounds too good to be true! — and raised a lot of questions: How is it possible that your e-fuels are so much cheaper than everyone else’s? And if you can make these fuels, then where are they? Why aren’t they for sale yet? I’m here to answer these questions.

What’s everybody else doing?

If we ignore biofuels and waste-to-fuels and just focus on fuels made partially or fully from electricity from renewable sources, then everyone else who’s making e-fuels is using high temperature, high pressure synthesis. It’s been possible for almost a hundred years to make synthetic fuels from H2 and CO2 by using the Fischer Tropsch process, (invented in 1925), or similar processes that use high temperature and pressure with a catalyst to combine carbon and hydrogen into fuels. Currently, there are many companies using Fischer Tropsch or related processes that call their products e-fuels, which technically can be true if they only use electricity for CO2 capture and desorption, hydrogen generation, CO2 to CO conversion, synthesis reactions, and downstream cracking and distillation. In practice, it’s common to use fossil methane for the heat needed in these processes and to try to justify the additional CO2 this emits by promising to capture it also. Regardless of how closely they keep to the electricity-only ideal, however, none of these approaches can compete with fossil fuels on price.

What’s new about our process and why do our e-fuels cost so much less that they can compete with fossil fuels?

- Electricity is really cheap now

The first reason our fuels have such a low cost is not specific to us — it’s the recent abundance of really cheap renewable power. E-fuels are stored renewable energy. The day has long been anticipated when the cost of renewable electricity would become low enough to enable e-fuels, and that day has come. Specifically, it arrived in 2018, when the cost of utility scale solar power dropped to $0.02/kWh for the first time in a purchase by the city of Los Angeles. This marks a drop of over 90% in just ten years. The most recent record for the lowest utility scale solar bid was achieved last year at $0.01/kWh. The dramatic drop in costs is due to massive investment in solar panel manufacturing and in learning-by-doing cost reductions from making lots of solar panels. Low cost electrons mean low cost e-fuels.

- We don’t need pure CO2

The second reason our fuels are low cost, and one that is specific to us, is that we don’t need pure CO2. In order to make hydrocarbon e-fuels at scale one needs to capture CO2 from the air by direct air capture (DAC). For everyone else making e-fuels, this is a large cost. This is because their processes all require pure, pressurized CO2 gas. One obtains CO2 from the air by adsorbing the CO2 into or onto something, typically an amine liquid or amine functionalized bead, or in a hydroxide solution in water, or something more exotic, like an ionic liquid. This part isn’t so hard, and doesn’t require much energy, just a fan to blow air. In some cases, passive wind is used, but in either case, it’s not the main energy consumer.

The main energy cost is in getting the CO2 to release from the absorbent — to desorb. And that’s when things get really expensive, because this requires a lot of energy, almost always in the form of heat from burning fossil methane or a portion of the fuel produced. This is why most DAC CO2 processes cost $500-$600/ton of CO2 with a far distant and hopeful target of $100/ton at scale. But even at $100/ton CO2, any fuel one goes on to make is already too expensive to compete with fossil fuel.

At Prometheus, we don’t make or need pure CO2 gas, so we don’t need to desorb it. Therefore, we avoid the vast majority of this cost. Instead, we capture CO2 in water and then use it in water to make fuel. ARPA-E refers to this as “reactive CO2 capture” and identifies it as a significantly lower-cost DAC approach. Because our DAC tech is fundamentally different, our cost to capture CO2 is only $36/ton, the lowest in the world, and the only one low enough to enable fuel that competes on price with fossil. (More on this below.)

- We use electrocatalysts, not catalysts that need high pressure and temperature

The third reason our fuels are low cost, and another reason that is specific to us, is that we use electrocatalysts to do what only pressure and temperature could do before. The first widely read paper on this showed that CO2 in water could be turned into ethanol at a faradic efficiency of 63%. This means that 63% of the electrons that went into products in the process went into ethanol. We licensed a second-generation of this catalyst that has even better performance, making much larger and more complex carbon-based fuels with electricity alone.

Using electrocatalysts instead of the high pressure and temperature catalysts everyone else uses gives us a big reduction in cost because we can do the same job at room temperature and pressure while using much less expensive materials. It’s also great for our system performance because we can turn our process on and off quickly, matching intermittent solar and wind power. High pressure and temperature systems can’t operate like that.

- We’re the only ones who don’t need distillation

The fourth reason our fuels are low cost is that we’re the only company in the world that can replace distillation with nanotechnology to separate fuels from the water in which they’re made. In my previous startup, Mattershift, I commercialized a carbon nanotube (CNT) membrane, and published on it in 2018. Numerous academic publications have shown that membranes like this could separate alcohols from water, but until Mattershift produced them, no commercial CNT membranes were available. Previously, the only way to separate alcohols from water was to use distillation, another highly inefficient and expensive heat-based separation process. The CNT membranes solve this problem, using over 90% less energy than distillation and dramatically lowering the cost of extracting our fuel. This is a big deal because it reduces what is a major cost for other e-fuel makers to a minor cost for us.

Ok, that sounds good, but how does all this compete with fossil oil and gas?

The math on the cost of our e-fuel is pretty simple. The only inputs are air (CO2 and water) and electricity, and the only outputs are oxygen and fuel. The cost of the inputs plus the cost of the equipment and its maintenance make up nearly all of the [operating] cost. There are some other operating costs, like the vacuum pump and coolers on the CNT membranes or the power for pumps and controls, but these are less than 1% of total operating costs. I won’t include taxes or delivery fees since these vary a lot from place to place.

The main cost is electricity. The energy density of liquid e-fuels is very high, the main reason that they have long been desired as a solution for decarbonizing long-haul shipping and aviation. For gasoline, the energy density is approx. 33 kWh/gallon. In a TEA study we did last year with a third-party engineering firm, the estimate for the overall efficiency of our process (chemical energy in the fuel / electrical energy used to make it) is approx. 43%. This is a really great efficiency, because it includes everything involved from start to finish, including DAC of CO2, synthesis of the fuel, and separating the fuel so it’s ready to use. At this efficiency, our gasoline will need approx. 77 kWh of electricity per gallon. If the cost of power is $0.02/kWh, then the electricity cost of our e-gasoline is $1.54/gallon.

The next cost is CO2. The third-party TEA put our DAC cost at $36/ton of CO2 at $0.02/kWh, making it the lowest cost DAC in the world, and this cost drops further with lower costs of electricity. A gallon of gasoline contains approx. 8.9 kg of CO2 per gallon, so at a cost of $36/ton, this results in a CO2 cost for us of $0.32/gallon.

The most important cost after electricity is equipment cost, typically called capital cost. Adding up the electricity and CO2 costs, we get $1.86/gallon. If we want to stay below $3.00/gallon (for example), then we need to keep the capital and maintenance costs less than $1.14/gallon. Our cost models tell us that we can have capital and maintenance costs that are significantly lower than that, due to the advantages listed above, including not needing CO2 desorption or fuel distillation equipment, using low cost materials due to low temperatures and pressures, and deploying mass manufacturing methods like those used to make cars.

[Read more here ---the rest of the article is interesting, too.] 

The critical part of this process is the carbon nanotube membrane.  Without that, dissolving CO2 into water to produce hydrocarbons by electrolysis would be pointless, because you'd need distillation, which needs lots of energy and is expensive.  With the membrane, you just simply "sieve" the water, and the alcohols---from which petrol, diesel and jetfuel can be made---are left behind.

Petrol is currently trading at bulk at ±$2.50 per gallon, or $0.60 per litre.  So for this process to be profitable, it would need to have a capital and maintenance cost below $0.50 per gallon.   Except, that, if this works, then it will qualify for carbon credits.  For example, at a carbon price of $50/ tonne of CO2 emissions, a carbon credit would be worth roughly ±$0.45 per gallon.   For each $10 rise in the carbon price, petrol prices will rise by roughly 10 cents a gallon. 

More to the point, long-distance air and sea transport is still not possible with batteries, though it may well be in 10 years from now.  Also, fossil fuels will provide long-term storage for the grid---diesel generators using green diesel will be able to back up the grid.  We wouldn't have to worry about "dunkelflaute"---when it's cold and still and dark, so electricity demand is high but renewables supply is low.  

Let's hope that this process does work and that it soon scales up.  In my opinion, it looks as if we're still a couple of years away from commercialisation.  But by then, the pressure to de-carbonise will only have grown, as El Niño drives global temps towards the 1.5 degrees above pre-industrial times.

CO2 to jetfuel

Air Company's Chief Technology Officer Stafford Sheehan, pictured left, and CEO Gregory Constantine (Air Company)

From Canary Media

The startup Air Company first made a splash three years ago by distilling vodka using captured carbon dioxide. At a converted nightclub in Brooklyn, New York, the company built a maze of tubes and tanks to turn the greenhouse gas into spirits — no grains or potatoes required. Since then, Air Company has tweaked its technology to produce another coveted, crystal-clear liquid: sustainable aviation fuel.

On Thursday, during Climate Week NYC, the startup unveiled a second, larger chemical reactor in Brooklyn. Air Company is now making small batches of CO2-derived jet fuel, including a 5-gallon order for the U.S. Air Force, which recently used the fuel to fly a large drone in northern Florida.

Still, Air Company will need to scale its production exponentially if it’s going to fulfill its latest tall orders.

JetBlue, Virgin Atlantic and other aviation firms have agreed to buy 1 billion gallons of Air Company’s sustainable aviation fuel over the next decade, the companies said this week. The announcement follows a $30 million investment round in April led by Carbon Direct Capital Management and including JetBlue’s and Toyota’s venture capital arms, which brought Air Company’s total funding to $40 million.

“Our technology and the products that we make are really a stepping stone to get to massive commodities,” said Gregory Constantine, CEO of Air Company. Along with vodka, the startup makes perfume and hand sanitizer using carbon dioxide captured from beverage manufacturing plants, which produce waste gases during fermentation.

“From a decarbonization point of view, [aviation] is where we can have the most climate impact,” he told Canary Media.

The global aviation industry contributes more than 2 percent of global greenhouse gas emissions every year, a share that’s expected to soar as passenger air travel grows. Many aviation analysts agree that sustainable aviation fuel, or SAF, will play a key role in reducing emissions from long-haul flights and larger aircraft. Batteries and hydrogen, meanwhile, are expected to power mainly short-haul and regional flights.

Airlines currently use minuscule amounts of sustainable aviation fuel: about 26 million gallons in 2021, or well below 1 percent of total jet fuel demand. Nearly all existing SAF production uses corn, soybean, animal fats or used cooking oil. As industry demand increases, experts warn that relying on such materials could displace food supplies, drive deforestation or perpetuate industrial animal farming.

The Biden administration aims to increase U.S. production of SAFs to 3 billion gallons per year by 2030 — an effort that recently received an important funding boost under the Inflation Reduction Act. While airlines and aviation experts applauded the law’s SAF provisions, some critics say the policy risks detracting from other, more immediate solutions to reducing emissions from flying, such as improving aircraft fuel efficiency and electrifying airport equipment.

“Rather than putting all our eggs in the basket of sustainable aviation fuels, we need to have a more comprehensive approach,” said John Fleming, a senior scientist at the Center for Biological Diversity’s Climate Law Institute.

On a quiet commercial block in Brooklyn’s Bushwick neighborhood, Air Company’s leaders showcased the new reactor.

The startup’s technology begins with just two ingredients: carbon dioxide and hydrogen. The latter element is produced on-site using an electrolyzer, a boxy device that splits water into hydrogen and oxygen using electricity. A chemical reactor combines the CO2 and hydrogen using a metal catalyst to produce either ethanol (ethyl alcohol) for consumer products, or paraffins — colorless, oily liquids — for sustainable aviation fuel.
Air Company says its new CO2-based aviation fuel has the potential to reduce greenhouse gas emissions by more than 97 percent compared to traditional jet fuel. Twelve says its E-Jet product has roughly 90 percent lower life-cycle emissions than conventional jet fuel — a figure that includes the carbon emissions associated with manufacturing solar panels or wind turbines used to power the electrolyzers.

[Another startup, Twelve] uses electricity and catalysts to split CO2 into carbon monoxide and also split H2O into hydrogen. This produces a synthetic gas. (Typically, ​“syngas” is made by burning coal, fossil gas or biomass.) In a second step, Twelve’s syngas is run through a series of chemical reactions known as the Fischer-Tropsch process to create liquid hydrocarbons.

Twelve began producing its first batches of E-Jet a year ago, as part of a pilot program with the U.S. Air Force. The startup is now working to build a much larger plant to produce fuel for its partnership with Alaska Airlines and Microsoft, according to CEO Flanders.

Hydrogen efficiency will beat expectations

 From a Twitter thread by Gniewomir Flis

Hydrogen efficiency will beat expectations After spending the last six months looking at cutting edge hydrogen tech I believe that the prevailing view that hydrogen is inefficient needs an update. There’s much innovation to be excited about on the horizon.

Take this T&E [Transport & Environment] chart for instance, which assumes that electrolysis is 76% efficient, and fuel cells are only 54%, which together account for the bulk of the losses. Almost every paper out there uses similar, often worse, numbers.

Current tech is already better than that. For instance, Nel’s stack can be up to 93% efficient (3.8kWh/Nm3 H2). Those numbers are rarely achieved in practice though as the stacks are run at higher current densities (=lower efficiency, but less capex)

But efficiencies are getting better. See the performance of the Oort Energy stack. 90% efficiency at 2A/cm2. This is not some experimental stuff, it’s a full sized stack ready to be manufactured.

In addition to high efficiency, Oort can electrochemically pressurise H2 internally to 200 bar at less than half the energy cost of mechanical compression.

You may also have heard of Hysata which set a record breaking efficiency (98%), though tech is still several years away from commercialisation as it has serious degradation problems.


But more innovation is coming. From the less conventional architectures, we’ve got H2Pro which claims 95% efficiency. So, upcoming electrolysis solutions are looking pretty efficient to me, a step up from the 70-75% efficiencies assumed by many today.

On the fuel cell the innovation is just as good, if starting from a lower baseline (50%). The technology to watch for is high temperature PEM. By high temperature I'm referring to 200C, which aids in rejection of water, a rate limiting step.

Practically, this means that high temperature PEM fuel cells would enjoy a 30% increase in efficiency, i.e from 54% to 70%. Several companies working on this, like Hy-point, Advent, or Mebius. [See this article in Electrive]

Applying these innovations to the T&E chart: Hydrogen production with storage is now 82% efficient.

Round trip efficiency is now 54%, so only 1/3rd less efficient than using electricity directly. Compare with 42% T&E had assumed for… 2050!

And that’s not the end of it. In the storage part, companies like @RuxEnergy (metal organic frameworks) or @VerneH2 (cryocompression) are almost able to match the density of liquified hydrogen without 40% energy loss.Does this change the calculus for hydrogen? To a certain degree. On the road batteries have a significant first mover advantage which I think they’re likely to retain, especially since this up and coming hydrogen innovation won’t get commercialised overnight.


But hydrogen might feel a boost in heavier and infra sensitive applications. I think regional aviation will be a good case in point. Heavy trucking and construction too. Trains could be a good one.


High temperature process heat is another one which would also get a boost. Even if heating with hydrogen is 12% less efficient than with electricity, it may be simpler to repurpose gas infrastructure than it is to lay hundreds of MW of new lines. EU modelling sees a role here.


To conclude: electrolysis is becoming much more efficient than the 70% it gets quoted on. Fuel cells are also getting better. Does this mean we’re all getting FCEVs and hydrogen boilers in 2030? Probably not, but other applications may get a hydrogen boost.


To conclude: electrolysis is becoming much more efficient than the 70% it gets quoted on. Fuel cells are also getting better. Does this mean we’re all getting FCEVs and hydrogen boilers in 2030? Probably not, but other applications may get a hydrogen boost.


Perhaps the real prize here is not that FCEVs are more efficient, but that we will need much less renewable energy to introduce green hydrogen in feedstock applications.

See also his corrections in this thread

The key point is this: producing hydrogen from electrolysis is going to become much cheaper, and hydrogen fuel cells are going to get more efficient. That will mean hard-to-de-carbonise sectors like heavy-duty trucking, air transport and sea transport will be able to switch to hydrogen from fossil fuels. More efficient electrolysis will also make power-to-gas (producing green hydrogen to be later used to make electricity in the grid) will become much cheaper, allowing us to reach the holy grail of long-term storage via methane.

Making jetfuel out of carbon dioxide

 From Phys.org

A team of researchers affiliated with several institutions in the U.K. and one in Saudi Arabia has developed a way to produce jet fuel using carbon dioxide as a main ingredient. In their paper published in the journal Nature Communications, the group describes their process and its efficiency.

As scientists continue to look for ways to reduce the amount of carbon dioxide emitted into the atmosphere, they have increasingly focused on certain business sectors. One of those sectors is the aviation industry, which accounts for approximately 12% of transportation-related carbon dioxide emissions. Curbing carbon emissions in the aviation industry has proved to be challenging due to the difficulty of fitting heavy batteries inside of aircraft. In this new effort, the researchers have developed a chemical process that can be used to produce carbon-neutral jet fuel.

The researchers used a process called the organic combustion method to convert carbon dioxide in the air into jet fuel and other products. It involved using an iron catalyst (with added potassium and manganese) along with hydrogen, citric acid and carbon dioxide heated to 350 degrees C. The process forced the carbon atoms apart from the oxygen atoms in CO2 molecules, which then bonded with hydrogen atoms, producing the kind of hydrocarbon molecules that comprise liquid jet fuel. The process also resulted in the creation of water molecules and other products.

Testing showed that over 20 hours, the process converted 38% of the carbon dioxide in a pressurized chamber into jet fuel and other products. The jet fuel made up 48% of the produced products—the others were water, propylene and ethylene. The researchers also note that using this fuel in aircraft would be carbon-neutral because burning it would release the same amount of carbon dioxide that was used to make it.

The researchers also claim their process is less expensive than other methods used to produce fuel for airplanes, such as those that convert hydrogen and water into fuel—primarily because it uses less electricity. They also point out that conversion systems could be installed in plants that currently emit a lot of carbon dioxide, such as coal fired power plants.