Bjorn’s Corner: The challenges of Hydrogen. Part 2. Ecosystem.

By Bjorn Fehrm

July 31, 2020, ©. Leeham News: In our series on Hydrogen as an energy store for airliner use we begin by looking at the needed ecosystem that can produce and distribute Hydrogen.

When I was skeptical about hydrogen as a means to propel our airliners three years ago, the main problem was the lack of this ecosystem. That year, in 2017, 13 transport and energy companies formed the Hydrogen Council, to create this ecosystem. Today the council has 81 members, with 22 joining in the last year, Figure 1. The list reads as Who’s Who in the transport and energy sector.

Figure 1. Members of the Hydrogen Council. Source: Hydrogen Council.

The hydrogen ecosystem is gaining momentum

Here the charter of the Hydrogen Council:

The Hydrogen Council is a CEO-led global initiative of leading energy, transport and industry companies with a united vision and long-term ambition for hydrogen to foster the energy transition. The coalition of 81 members including large multinationals, innovative SMEs and investors collectively represent total revenues of over €18.7 trillion and close to 6 million jobs around the world. The coalition has more than quadrupled in size since its founding in 2017 by 13 members. 

This grouping has the necessary incentive, knowledge, and firepower to establish the production and distribution capacity for ramping of a Hydrogen energy ecosystem.

EU has through it’s Clean Sky initiative sponsored a study of a Hydrogen powered aviation that was published last month, Figure 2.

Figure 2. The EU sponsored study for Hydrogen-powered air transport. Source: Clean Sky and EU.

It had Airbus and Boeing as participants, and several members from the Hydrogen Council contributed to the report.  It has the latest information on several topics around Hydrogen for air transport and we will quote from it as we go forward.

Our first extract is around the capability to support a change to Hydrogen for parts of the airline fleet until 2050 (the report sketches two scenarios for the Hydrogen ramp, an aggressive and an, in my opinion, more realistic ramp):

In the two scenarios, the global demand for hydrogen would reach approximately 10 or 40 million tons of LH2 by 2040 per annum, and approximately 40 or 130 million tons by 2050. This amount represents 5 or 20 percent of the total global demand for hydrogen projected by the Hydrogen Council by 2040, and 10 or 25 percent of global demand by 2050.

We see that the lower projection represents 5% of global Hydrogen production by 2040 and 10% by 2050, fully realistic quantities.

One of the contributors to the report is the French company Air Liquide, with experience around Hydrogen as fuel through among other sectors, the space launcher area. Here what it says about its aircraft Hydrogen research and experience:

Air Liquide has been working on introducing hydrogen in aviation since the early 2010s. A project supported by the European Union (EU), launched in 2013, demonstrated the feasibility of an airborne gaseous hydrogen tank to power fuel cells. It has clearly demonstrated gaseous hydrogen was not the solution for the propulsion of aircraft, given the large quantities required (several tons aboard) and that liquid hydrogen (LH2) is the only way forward.

We now believe that it is urgent to use flight demonstrators as the principal means of evaluating, maturing and validating the technology and the procedures required to use liquid hydrogen. This is the goal of the Heaven project, granted by the Fuel Cells and Hydrogen Joint Undertaking (FCH JU), where Air Liquide is in charge of the storage while the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR) will modify its existing “HY4” R&D platform by switching from a gaseous to a liquid hydrogen storage. The first flight will occur in 2022 and it will be the world’s first passenger aircraft powered by fuel cells fed with liquid hydrogen.

The announcements from the French and German governments where they support the development of a Hydrogen ecosystem and the first Hydrogen fueled aircraft until 2035 shall be seen in the context of European participation in the Hydrogen Council and different EU research programs.

There has been a lot going on behind the scenes around Hydrogen in the last year. The announcement on the 10th of June by the French Government that they support their industry with €15bn investments for, among other items development of the first Hydrogen powered airliner, was carefully coordinated with industry partners and the EU.

40 Comments on “Bjorn’s Corner: The challenges of Hydrogen. Part 2. Ecosystem.

  1. Very interesting to see that the (LH2-modified) HY4 prototype is fuel-cell-based rather than combustion-based. If that can be made viable for large commercial aircraft — which would surprise me — it will be a major victory against the environmental naysayers, who nag about the NOx produced by combustors.

    • Well, fuel cells are fine for efficiency, being 2-3 times as efficient as combustion turbines. They are low in power. So they could have a battery for takeoff and fly on fuel cells, and they may be able to charge the batteries. To avoid compression losses and the weight of steel, they could use liquid hydrogen in super insulated insulated or dewar tanks, and they have to boil it off to feed the fueld cells.
      So it is quite doable.

  2. LH2 is the fuel tanked into the Aircrafts but it will boil off and most likely will be compressed to be injected into the Engines. Those electrical driven compressors delivering a mix of H2 and LH2 to the Engines will not be cheap nor easy to certify or test at overhaul. So Honeywell, Argo Tech, Hamilton Sundstrand (now division of Collins) and Safran thru different turbopump parts suppliers like Fiat and GKN might jump ahead to get a good slize of this business before todays rocket Turbopump manufacturers see this mega business open up. (Ham. Sund. is already one of them)

    • RocketLab have a nifty line in electrically-powered pumps for their Rutherford engines. Currently for RP-1 and LOX, but should be worth looking at for LH2.
      Since these are specifically not turbo-pumps, they avoid all the complication and safety issues with pre-burners etc.

    • The path to H2 in the sir, will not include a combustion stage as the thermodynamic waste involved in a carnot heat engine(turbine), coupled with the cost of provisioning the hydrogen will reduce the system efficiency to a very low level. It would only be valid as a survival expediency as the earth warms too a much higher degree than now. Cargo dirigibles, lifted by NH3(ammonia gas has similar lift wrt heated air – even better?) with H2 fuel cells would be better than insulated bag hot air dirigibles. Storm/wind vulnerability would limit this approach.

  3. Transitioning to LH2 would be a good first step with HY4. But then large improvements in the technology and supply chain would be needed to scale up to commercial service. So a long way to go before this would be a reality.

    It may be that initial increases in hydrogen production will be consumed by terrestrial applications at first, many of which are more readily and rapidly feasible than aviation.

  4. AIR LIQUIDE has been a very serious and profitable giant for many years.
    therefore we can trust what it says;
    Air Liquide has been working on introducing hydrogen in aviation since the early 2010s. A project supported by the European Union (EU), launched in 2013, demonstrated the feasibility of an airborne gaseous hydrogen tank to power fuel cells. It has clearly demonstrated gaseous hydrogen was not the solution for the propulsion of aircraft, given the large quantities required (several tons aboard) and that liquid hydrogen (LH2) is the only way forward.

    conclusion is clear: gaseous hydrogen is dead.
    BUT: liquid hydrogen has also its own problems
    – is there any realistic way to have green liquid hydrogen on a large scale?
    – what is the tank pressure? and temperature? (we can read about 350 bars)
    – how can we locate these tanks in a plane? what is their weight?
    – loss by leakage seems to be a serious issue (BMW cancelled its program because of this) is there any new solution?

    • The problem might not be production of LH2 but to do it economically and environmentally sound, today the cheapest way is to use Natural gas into a hydrogen gas factory, like the gas Germany imports from Russia thru the Northstream pipes.
      To make enough electricity enviromentally sound, running a H2 electrolysis factory economically with latest Technology catalythic coating to reduce energy consumption and then transform it into LH2 and distribute is another.

    • Tank pressure & temperature depend on the storage design conditions. With cryo-insulation, LH2 can be stored as a subcooled liquid vented to atmosphere at 20 K, if you either tolerate evaporative losses or have a small recovery plant.

      However for mobile storage the tanks may be cryo-compressed, in that they are cryo-insulated but allowed to rise in temperature and pressure to maintain a saturated mixture of liquid and vapor. The highest saturation temperature for LH2 is 33 K (critical point), at about 13 atmospheres.

      Above that you have a supercritical state that is not clearly liquid or vapor or gas. In that case the pressure is the limiting factor (structural strength) with the temperature being controlled accordingly. A vacuum-insulated cryo-pressure vessel might be rated at 275 atmospheres, less than that of a plain pressure vessel for H2 gas, which could be 350 to 700 atmospheres.

      As you fill or empty the cryo-compressed tank, the H2 may pass through all the thermodynamic states above, so cooling must be supplied for filling and heat for draining, in order to fully utilize the tank storage capacity.

      It’s a complicated process overall. Here is a good study of automotive cryo-compressed storage tank design, including full-cycle economic analysis of H2 production, storage, and delivery:

      • Interesting: for Aircrafts the pressure builds up after tanking LH2 until APU start (either gas turbine or fuel cell). Don’t really know how and ideal Aircraft fuel pump for a gas turbine feeding a mix of H2 and LH2 to burner pressure shall be configured as you really don’t want to compress H2 gas to over 30-50 bars burner pressure due to the shaft power required. I know that rocket Engines can pump LOX and LH2 (hydrogen rich) to a preburner giving Power to the turbopumps having enough pressure after the turbine to be injected into the main rocket Engine burner but that setup sounds risky and expensive for Commercial Aircrafts.

        • The study link I gave was for PEM fuel cell with a regulated H2 gas supply pressure of 4 atmospheres. For a gas turbine, fuel pressures would be more on the order of 15 to 30 atmospheres.

          For aviation where you need to consume a large fraction of the fuel tank volume, you would have to use H2 gas at the burner and not liquid, as liquid would only be available at certain tank conditions. For a cryo-compressed tank, you’d have the required pressure initially but would have to add heat or use a compression boost (or both) to maintain constant fuel pressure during the entire flight.

          This is all feasible but requires careful & coordinated operation of the tank, engine, throttle, and other fuel regulating mechanisms. You couldn’t just assume the fuel is available to the engine at all operating conditions. Computerized tank & engine controls should make that possible. But it would be a new level of complexity.

          • Having large amounts of coolant can be used to cool the HPC and make it run more efficient and thus feed the burner with much cooler air. This can be used either to increase Power to todays Tubine Inlet Temp or run the Engine much cooler in the hot section.
            Letting the burner heat gasify LH2 and premix with air a few millisec before hitting the burner heat for combusiton is a proven Technology (RR)

          • All those things are possible, yes. But to have LH2 available throughout the tank capacity, would require carefully controlled tank conditions.

            The liquid state for H2 is in a fairly narrow band of temperature and pressure (see phase diagram). From the triple point to critical point is only about 20 K differential. The equivalent pressure differential is from 0.1 atm to 10 atm.

            So at a vented 1 atm you’d need constant cooling throughout the flight, or let evaporative losses absorb the inevitable heat leakage, or have a recovery/liquefaction plant. If you allow pressure to rise in the tank with heat influx (a cryo-compressed tank), that could work initially until you reach 10 atm, at which point you’d have supercritical fluid, and would have to reduce back to liquid again before consumption.

            If you have a terrestrial tank, it can be large enough to be vented with liquid always present, along with a recovery plant to minimize losses. Or with a vented launch booster tank where the H2 is consumed in a few minutes, so you don’t care about losses.

            More difficult to do that in an aircraft that flies for several hours, with volume and weight restrictions on the tanks and support equipment, and with atmospheric pressure decreasing with altitude. These are some of the challenges that will need to be addressed.

          • @Rob, for LH2 tanks in Aircrafts you have fuel consuption by the Engines almost instantly after fuelling hence any LH2 boiling off are consumed by the Engines together with some LH2. After landing the Aircraft needs to be defueled and the hydrogen taken to the Airport LH2 process plant. The question is how high pressure the aircraft tanks will be certified to. By tradition 100psi is common shop pressure. Industry is moving to AGA Genie 300 bar Composite overwrapped pressue vessel bottles from 200 bar steel bottles and it might be that “torpedo size” 20″ dia Composite bottles of different length becomes the Aircraft LH2 standard.

          • Claes, at those pressures you don’t have LH2. To have liquid you need lass than 10 to 15 bar.

            The point I was trying to make was that the fuel tank has to be controlled and operated as a component of the fuel delivery system.

            If you burn H2 as gas, that lessens the tank restrictions as you can have a variety of phases in the tank. This is the trend in automotive tanks (cryo-compressed).

            If you burn LH2, then the tank phase becomes more critical, or you need conversion equipment to adjust the phase of fuel flow.

            So there are tradeoffs involved. Burning the evaporative loss as a means of recovery could work if you have two burners, or a pre-burner. In that case you are regulating the tank pressure as a method of operation. Obviously a lot would depend on the relative rates of flow.

  5. Although this has specific ecological benefits , it is premature . The main reason being that vast quantities of hydrocarbons would be burned , in order to produce and transport the hydrogen in question . The “greenest” strategy would be to wait until most of the energy needed for these , could be produced by renewable energy sources .
    Additionally , the voluminous nature or LHy will require much bulkier aircraft , with highly specialized and expensive storage and distribution systems . This for everthing from the production facilities to the aircraft themselves .
    All-in-all , this is a most worthy goal , but it’s time has not come yet . We should do the preliminary research , but not jump the gun . .D.H. .🤔

    • I agree there are some elements of this which resemble the hype surrounding electric aircraft. In that case the limits of the energy storage technology were too great, as Bjorn pointed out, but the energy carrier itself (electricity) was readily available.

      In this case the technical energy storage hurdles are lower, but the supply of the energy carrier (hydrogen) is still some ways from being available. So it’s more feasible than electric but the investment needed is much larger. The aviation component is only one part of the problem.

      This is why it makes more sense to displace other uses of fossil fuels first, and as we do that, the technologies and supply will be developed to the point that aviation would be among the last applications, as the highest-hanging fruit with the least return on investment.

  6. While I have never run a GT with LH I have run diesels with it. The mass flow of gas H2 is staggering if you are burning gas, but we had one system that delivered liquid using tank pressure and injected liquid directly.
    There are also uses for the LH since it is cold, cooling air, oil, and critical engine components are also also possible.
    LH is actually reasonable easy to handle and work with.
    Making the H2 by a ‘green’ method may actually be the largest huddle.

    • not only for the curious!
      this report MUST be read.
      Not only because it is done by MAC KINSEY, obviously the most prestigious (and costly) signature.
      But because it is certainly the base on which recent H2 décisions were made.
      and a careful reading shows two things:
      – the biggest challenges of H2 are mentioned, but usually swept under the carpet (p43 supplying one hub airport wouls require 4 large offshore Wind parks!)
      P34 SA aircraft will be 10m longer due to tanks. How can airports cope with this?
      some very courageous assumptions are made (just one example: cost of LH2 divided by 4 until 2050! P49)
      and there are many other challenges only mentioned…
      Worth a critical read, definitely

  7. The first accident will be the end of Hydrogen airplanes.
    They will be like small nucular bombs when loaded.
    Remember the Hindenberg?
    The answer is captured carbon combined with Hydrogen.
    A simple hydrocarbon that is carbon neutral and safe.

    • “They will be like small _nucular_ bombs when loaded.”

      Are you referencing GWB’s thesis on how to avoid military service? 🙂

      H2 is a lot less dangerous than some other ignitable volatiles.

    • The Hindenberg was blown up with an on-board bomb. The flames seen in the film clip were burning kerosine fuel. Hydrogen ignites only at a very narrow range of mixtures with air. The hydrogen released from the Hindenberg went up up up.

      No aircraft design is noted for bomb resistance.

      • Well, gas filled = high risk. Liquid hydrogen is a lesser risk. It will be in a low temperature storage tank connected to the fuel cell assembly via vented conduits with enough air flow to keep any leaked hydrogen below the lower explosion limit. They will also have hydrogen detectors of modern design of the type that did not exist when the hindenburg flew. Aviation gas is also very flammable, yet is contained well with modern piping (that is inspected often).
        That said, any hydrogen craft will need the very best in precautions. There are ways to store hydrogen as a hydride which lowers the energy density at greatly increased safety.

  8. “The next largest segment, medium-range aircraft, requires significantly extended fuselages for LH 2 storage

    thus The exact climate impact of non-CO 2 emissions of aviation is a matter of scientific debate. Please see chapter 1 on climate change for estimates by
    technology and annex 1 for the methodology and sources behind these estimates.

    H2 combustion could reduce climate impact in flight by 50 to 75 percent, and fuel-cell propulsion by 75 to 90 percent.

    would consume about 25 percent more energy than conventional aircraft; these aircraft would lead to a cost increase of 30-40 percent per PAX. ”

    So, we have a pretty pictured of an H2 powered bird flying over Seamills, but that does not address if you take Wind away to make Hydro, that the rest used for society has to be sourced from other.

    Note the longer fuselage and higher pax costs. Then offset by CO reduction (supposedly).

    So, what I see is a lot of hardware companies looking at a slice of the pie.

    How about just making clean diesel (Kerosene)?

    No sulfur or other impurities (as I recall, current Jet A is loaded with allowed Sulfur unlike diesel fuel for cars and equipment)

    Note the scheme uses fuel cell for small aircraft and hydro burn for LCA.

    Clearly back int he day with the first IC engines, crude as they were they had a lot of upside and rapidly (due in large part to WWI) got some impressive power density gains.

    As the gains waned (for large aircraft engines) the Jet came alone and had the same upside using the same basic infrastructure.

    Inventing a whole universe on a premises that does not look or compare to alternatives is just another government driven pie in the sky.

    Anyone remember er the previous one of Open Rotor? So yesterday.

    • “No sulfur or other impurities (as I recall, current Jet A is loaded with allowed Sulfur unlike diesel fuel for cars and equipment) ”

      The spec allows 3000ppm.
      market typical is 300..600ppm apparently.
      i.e. .03 .. .06 %
      EU automotive diesel “no sulfur” contains <10ppm

      • And the point is?

        Make Jety A the same as auto (same <10 in US) and you clean it up hugely.

        Easy improvement no one talks about.

        • ULSD was done mainly because it permits emissions control technologies for particulate matter. That was important for reciprocating intermittent combustion engines. The secondary benefit is sulfur emissions reduction.

          The EPA did not require the same for jet fuel or home heating oil because those applications use steady-state combustion. So particulate matter emissions are already greatly reduced and there is not the same need for exhaust treatment.

          The cost differential of ULSJ is not huge (less than 10 cents per gallon for all methods), but still significant for airlines. The EPA may eventually mandate it, for the sulfur emissions benefit alone.

          • As I said, cheap easy fix. Low hanging fruit. All combustion processes created emissions.

            Aviation simply has managed to make itself exempt like the shipping industry (lot of pie in the sky stuff like we are buying new aircraft for the environment, Bull – we are buying new aircraft because we think its to our advantage)

            NOX in particulate (yes that was intended) gets worse at high temps. If there is anything a Jet Engine is good at is high temps. It has nothign to do with the varying combustion process.

            And what are we doing with Jet engines? Yep, running higher temps all the time.

            And the cost (whatever it really is) of processing happens to everyone, its a neutral field if everyone has to buy no sulfur Jet A.

            The sulfur from the de-sulfur process is sold for industrial process, so, it does cost to remove it but they get money back. Ergo, its in their interest to insist its a cost but they don’t want to list the return so they can charge higher.

          • All combustion processes create emissions, but not equally. Steady state combustion in turbines and furnaces is by definition cleaner than intermittent combustion in reciprocating engines. EPA recognized this based on the science, and ruled accordingly.

            Marine fuel is subject to similar regulations beginning this year, again because ships mostly use reciprocating engines. Farm equipment was initially exempt but now is also covered, again because of reciprocating engines.

            As I said, EPA may eventually extend to aviation, or to home heating, based on advancing emissions standards.

    • Why the extended fuselage?
      Remember that all passenger aircraft have a “dowstairs” (cargo hold), which is generally under-utilized. LCCs certainly don’t carry cargo, because the associated loading/unloading times would disrupt their fast-turnaround model.

      Having equipment (evenly distributed) in the cargo hold would also be better from a center-of-gravity / center-of-lift point of view.

      The past few months have shown that the cargo normally carried in the holds of passenger aircraft can also be efficiently carried by a relatively small number of dedicated cargo aircraft. In fact, since cargo isn’t subject to “flight-shaming”, carrying cargo in conventionally-fueled aircraft is something that could carry on for quite some time after passenger aircraft had transitioned to LH2…after all, cargo carriers rarely have a problem using older birds.

      • Safety issues exist with carrying LH2 below the passengers. Hydrogen rises if a leak occurs, so the fire risk would be above the tanks. Also the cargo area is considered a crush zone in the event of an accident, but the energy release with crushed LH2 tanks would be enormous,

        Having a separate and isolated fuselage section for tanks, with venting mechanism, would be better for safety reasons as fire, leakage or burst vessel release could be kept away from passengers. But it may not be very practical given the large volume required.

      • So why not just fill the hold with a Jet A1 and fly round the world?

        • Note that people are ignoring the fact that on LR single aisle models, there are fuel cells in the belly. Also true of the LR A350-900 Singapore super LR.

          You simply are trading pax for fuel, its the weight.

          For Hydro, its the container shape at issue. A ball is the best for pressure. You make it longer, then it has to have heavier walls (or move exotic stronger materials).

          Ergo, you need longer to put in a cylindrical tank which means more weight and efficiency losses.

          The belly on a single aisle is stuff full of baggage. Its not just sitting there empty.

        • Jet A1 makes CO2. and water on combustion. Hydrogen makes only water. Hydrogen is light, so a huge cryo tank of liquid hydrogen might make it around the world – but diseconomic = why do it.

  9. I do not believe in Hydrogen. The distribution system will be to costly to build in comparison to use a liquid hydrocarbon fuel as energy storage and fuel made with electrical power, Water and CO2. A lot of research is done on this by Universities and Car Manufacturers.
    Methanol is the simplest to make, but for aviation use ,it will probably be better with a similar fuel to JetA1.

    • The biggest Gas companies in Europe are Linde in Germany and Air Liquid in France, both countries lack massive oil/gas fields but have Siemens, Enercon in Germany and Alstom and Areva Nuclear in France bedides the Danish windmill factories. So EU’s heavyweights can decide its the way forwad when the UK with BP and Shell interests outside EU (I kn0w part of Royal Dutch Shell is EU)

      • As I said, self serving.

        If you have a hammer then a nail is the fastener of choice.

        The Soviet jet diagram makes it clear, you need a big all by itself section for Hydro.

        • Airports will become hydrogen storage depots. There is zero hydrogen loss, with an actively cooled large storage facility. Any outgassing is condensed and put back in the tank. Airports in general have areas where hydrogen can be stored off the flight line. Some exceptions, that will use cryo piping to offsite storage.
          Cars will never be hydrogen fueled, they have a diseconomy of smaller scale

  10. LH2 seems a poor choice for aircraft fuel, if only from the common sense perspective of having a -240C highly explosive and ‘seepy’ liquid/gas, subjected to inertial stress, vibration etc, so close to several hundred passengers.

    I thought the front-runner was butanol, which was supposed to be an almost drop-in replacement for jetA? That it ‘burns to co2’ is irellevent if it can be made by capturing co2, eg bio-butanol, or other carbon-capture technology.

    Since LH2 is still lacking an efficient and environmentally friendly manufacturing process, I think we should concentrate on a fuel that makes more sense, and work to validate butanol as a fuel, and on efficient production methods.

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