(Guest Post by John Murray)
There has been much discussion for over thirty years or more around the use of hydrogen fuel cells as an alternative to the internal combustion engine. Fuel cells had been promoted in some sectors as the best alternative to the internal combustion engine. Proponents believe such a car could be easily refuelled with hydrogen and assumed it would have greater range than a pure all-electric car. Recent developments in lithium ion batteries, and the consequential range improvements of EVs has significantly dampened enthusiasm for hydrogen fuel cells. Little seems developed in any wide commercial sense and certainly not to the extent of the pure electric car. Honda have produced the Honda FCX Clarity FCEV, a hydrogen powered Fuel Cell Electric Vehicle (FCEV), which they are leasing in limited numbers to selected customers in specially selected locations only. Similarly, Toyota released its Hydrogen Powered Mirai, but again only in selected locations and to selected customers. There are several reasons for this approach and understanding a little more about fuel cell vehicles may explain why.
It is important to realize that a fuel cell car is actually an electric car. The Honda FCX Clarity FCEV and the Toyota Mirai FCEV, both use an electric drive motor and a battery pack. So, fuel cell cars have some of the advantages of pure fully electric cars. The motors are highly efficient, they have the same torque characteristics and they are silent. The hydrogen fuel cell in the FCEV acts to keep the battery charged, but can directly power the electric drive motor, similar to the function of a gasoline-powered range extender. In essence the FCEV is firstly an electric car with a hydrogen fuel cell range extender added. Both the battery and the fuel cell use chemical reactions to produce electricity. More significantly it must be realized that hydrogen, just like a battery, is not an energy source in itself, but simply a means of storing energy. The energy stored within hydrogen has been imparted from electrical energy through the electrolytic hydrogen production process or more likely in the refinement of fossil fuels such as coal seam (methane) gas – both are energy intensive processes in themselves.
The FCEV takes on hydrogen fuel in a compressed gas cylinder similar to, but much stronger than an LPG cylinder. As hydrogen has an extremely low energy density it has to be highly pressurized (over 700 atmospheres) and this process in itself takes a lot of energy beyond the actual production of the hydrogen. During travel, hydrogen is routed to the car’s fuel cell which, through the use of a catalyst, separates its protons and electrons at the anode. The electron flow goes via the car’s lithium-ion battery, in essence keeping it charged, and recombines with the protons and oxygen at the cathode. The only by products are water and a fair degree of heat, the latter indicating a degree of inefficiency and wasted energy. Nonetheless, hydrogen fuel cell cars are, like pure battery powered cars, classed as Zero Emission Vehicles (ZEV).
So why haven’t FCEV becoming as prolific as other electric cars? The reasons are numerous.
First, hydrogen is not as readily attained and certainly not as available as ubiquitous electricity. Most commonly it is refined from conventional coal seam gas, often termed ‘natural gas’ to greenwash what it really is, in essence just methane found with other fossil-fuel deposits. If taken from such sources, hydrogen is a fossil fuel, and is not a renewable resource. In addition, it is subject to similar refining, storage and distribution costs currently associated with petrol and diesel, including upstream CO2 emissions where the electricity required is usually generated from fossil fuels. As already mentioned, it also needs to be highly pressurized to gain any useful energy density and this takes further energy. Hence its supply would not be cheap, renewable nor sustainable in the long term. Thus, if taken from such sources, hydrogen represents a stupid energy pathway and an expensive and temporary solution at best.
Second, while hydrogen can be otherwise produced through the electrolysis of water, this process requires huge amounts of clean and fresh water – a vital and highly valuable commodity of life that can’t be wasted. Also, electrolysis of water by definition requires electricity in addition to the already mentioned pressurization, storage and distribution costs. It is actually the energy in the electricity used for electrolysis that is imparted to the hydrogen i.e. hydrogen is simply a storage medium for the electrical energy. Why not simply use the electricity directly to charge electric cars via the already available distribution network – the electricity grid? Every time there is a conversion of energy from one form to another there are efficiency losses – a concept known as ‘energy vector transition’. It seems completely illogical to use large amounts of electricity to produce hydrogen and then have to use more energy to highly compress it, to be then decanted and physically transported via trucks (even more dangerous than current petrol tankers) through costly distribution networks, only to be decanted again into cars and ultimately reconverted back into electricity in the fuel cells of those cars. This process cannot be more efficient, cost effective or safer than the direct use of electricity from the grid (or the sun) to charge an EV. Again, the hydrogen pathway represents a stupid energy pathway. The mandating of any system such as this would only be about looking after the interests of ‘middlemen’: oil and gas invested companies who would invariably transition into this market as both supply and/or demand for oil recede.
Third, the acidity of a substance is determined by the amount of hydrogen ion present in that solution; the more hydrogen ions, the more acidic. Hydrogen ions are highly acidic and thus highly corrosive. For this reason the anodes of fuel cells need platinum to prevent rapid degradation. The cost of platinum makes hydrogen fuel cells an expensive proposition even in comparison to lithium-ion batteries. Hence, hydrogen fuel cell vehicles are intrinsically more expensive than pure battery-electric cars.
- a hydrogen plant explosion in Santa Clara, California, meaning Honda and Toyota had to provide rental petrol vehicles to their few FCEV owners[8],
- a hydrogen tank explosion in Gangrening, South Korea, killing two people and injuring several others[9] and
- an explosion of a hydrogen filling station in Sandvika, Norway, injuring two people and causing Hyundai and Toyota to cease sales of their FCEV in that country[6,7].
And these incidents are happening already without any widespread uptake of hydrogen FCEV as yet. The safety factors seem never considered with fossil fuels despite thousands of lives lost over the years from significant explosive incident across the world[12].
Finally, and as already indicated, hydrogen FCEVs require a large and expensive distribution infra structure, in order to enable long distance travel. In essence this mandates a complete billion dollar replication of the oil industry’s distribution network. Such an infrastructure will be more expensive than the current oil infrastructure because of the unavoidable pressurization needs to give sufficient energy density by volume. It is this infrastructure factor that has meant the Honda FCX Clarity is only available for lease in particular areas, i.e. those that have a hydrogen refuelling outlet. This factor too, means hydrogen powered FCEV will always be far more expensive to purchase and operate than a simple battery electric vehicle.
In comparison to a pure battery electric vehicle, FCEVs are more complex and heavier. They require all the component parts of the simpler pure battery electric vehicle plus expensive fuel cells and hydrogen storage systems. Hence, they are likely to always have relatively poorer performance, be more expensive in initial purchase, in ongoing maintenance and per kilometre travelled costs. The use of hydrogen as a fuel for cars has a very poor Energy Return on Energy Invested (ERoEI) ratio as well as poor dollar return on dollar invested ratio relative to the pure all-electric car.
It is easier and cheaper to drive an all-electric Kona or Tesla across the country than it would a hydrogen powered FCEV. In fact, when compared to the Honda Clarity FCEV, the all-electric Tesla Model S has both greater range [Tesla 100D 572km (355mi) vs Honda 386km (240mi)] and greater efficiency (Tesla 89% vs Honda 60%). The Toyota Mirai can almost match the Tesla Model S 100D on range (Tesla 100D 572km(355mi) vs Toyota 512km(312mi)) but it does not exceed it and is certainly less competent in all other criteria, including performance and efficiency (Tesla 93mpg-e vs Mirai 66mpg-e).
Reinforcing this perspective, a 2018 paper from a team of Queensland university researchers “Where are we headed with electric vehicles?”[5] evaluated the comparative efficiencies of various power trains including ICE (petrol and diesel), FCEV, PHEV and the pure EV. This study did not just look at the efficiencies of the stand-alone vehicles but also the efficiencies of the full ‘well-to-wheel’ energy pathways. The hydrogen FCEV was shown to have a well-to-wheel efficiency of only 22%, compared with 20% for diesel and 14% for petrol. The pure EV had an efficiency of 67% across the full well-to-wheel analysis, three times that of the FCEV and almost five times that of the petrol-powered ICE[5], again highlighting the stupid energy pathways of fossil fuels. Hydrogen’s fuel-path inefficiency problems are also discussed in another paper by Tom Baxter of Aberdeen University, “Hydrogen cars won’t overtake electric vehicles because they’re hampered by the laws of science” [10]. Baxter details the unavoidable efficiency losses of the hydrogen fuel pathway due to the energy vector transition wherein energy is converted from one medium, electrical to chemical (hydrogen), back to electrical and finally to kinetic energy. Baxter puts the theoretical efficiency of hydrogen FCEVs at 38% at best, compared to 80% for a full battery electric vehicle, basically showing that the conversion losses for hydrogen energy pathways are little better than fossil fuels and fundamentally, inescapable.
“…and hydrogen vehicles come with the other great disadvantage of internal combustion powered cars, not being able to refuel them at home”
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A FCEV also has much larger drive train components than a pure EV thus encroaching on interior and storage space and significantly limiting design flexibilities. And hydrogen vehicles come with the other great disadvantage of internal combustion engined cars – not being able to fuel them cheaply at home. But there is yet another increasingly discussed advantage to the battery electric vehicle: the ability to be charged/fuelled from one’s own domestic solar panels. This essentially free and endless supply of energy is, and will increasingly be shown to be, one of the greatest advantages of EVs over any alternative power trains including over-hyped hydrogen.
Levi Tillemann in his book, The Great Race: The Global Quest for the Car of the Future writes,
“In fact, there was a running joke in the automotive community that hydrogen was the fuel of the future, always had been the fuel of the future and always would be the fuel of the future” (Tillemann, L. 2015, p127)[1].
Some believe that the promotion of hydrogen fuel cells for automobiles is little more than a distraction and delay strategy, seeding in people’s minds the notion that an alternative to gasoline is ‘just around the bend’. A hydrogen powered transport industry has been termed the “alternative-energy red herring” (Fletcher , S. 2011,p66)[3] and Tesla’s Elon Musk has called the concept of hydrogen FCEVs as “incredibly dumb”[5]. Intriguingly, Toyota’s chief engineer in charge of the Toyota Mirai project, Yoshikasu Tanak, recently stated “Elon Musk is right…. it’s better to charge the electric car directly by plugging it in”[4]. In effect, hydrogen as an alternative fuel source for passenger vehicles may simply be mooted to attenuate any sense of urgency around peak oil and global heating, and so prolong fossil fuel dependence while tempering any momentum towards an early shift to pure electric cars.
In summary I will leave it to the recent words of futurist Tony Seba from an interview with David Orban.
“Basically, it is storage [not an energy source]. So, the question is then ‘Can hydrogen compete with batteries?’, especially lithium ion batteries and what’s coming, and the answer is ‘No’. Hydrogen is a classic one to one substitution. Basically, [replacing] natural gas for hydrogen, [replacing] gasoline for hydrogen. It’s not really a disruption. It’s more political than anything, but if you look at purely the economics it doesn’t make any sense. If you look at the environmental aspects it also doesn’t make any sense. You know because 95% of hydrogen comes from natural gas but even if it came from water, the water utilisation the resource utilisation is just insane. I mean from a water perspective basically it would be preferable to use gasoline than to use hydrogen and then you have to build this trillion-dollar infrastructure, which again ‘Who’s going to pay for it?’.” …….. “So the hydrogen infrastructure…..think of it as like a natural gas infrastructure. You need big refineries, you need pipelines, you need gas stations. So it’s a brand new infrastructure at all levels, whereas the electricity network….we have an electricity network. We are going to improve it but we already have an electricity network. So the charging stations, you just need to plug into the existing network. So if you will, it [EV charging infrastructure] is a marginal investment in the existing network as opposed to a brand new infrastructure network. You know I look at things from purely economic reasons and you know, from an economic perspective it makes no sense. I mean you are going to have all the hype but you ask me that if in ten years we are going to have a hydrogen network, my answer is an unqualified ‘No’.” (Seba, T. 2020)[11]
John Murray
- Tillemann,L., (2015) The Great Race: The Global Quest for the Car of the Future. Simon & Schuster. New York.
- Fletcher, S., (2011) Bottled Lightning: super batteries, electric cars and the new lithium economy. Hill and Wang. New York
- Lambert, F., (2017) Toyota admits ‘Elon Musk is right’ but moves forward with fuel cell anyway https://electrek.co/2017/10/26/toyota-elon-musk-fuel-cell-hydrogen/ accessed 27/10/2017
- Muoio, D., (2016) Elon Musk explains why hydrogen cars are ‘incredibly dumb’ Business Insider http://www.businessinsider.com/elon-musk-hydrogen-cars-are-incredibly-dumb-2016-1/?op=1&r=AU&IR=T
- Smit, R., Whitehead, J., & Washington, S. (2018) Where Are We Heading With Electric Vehicles? Journal of Air Quality and Climate Change Vol 52 No 3 Sept 2018https://researchgate.net/publication/328782184_Where_are_we_heading_with_electric_vehicles accessed 4/12/2018
- Lambert,F., (2019) Hydrogen station explodes, Toyota halts sales of fuel cell cars, is this the end? Electrek https://electrek.co/2019/06/11/hydrogen-station-explodes-toyota-halts-sales-fuel-cell-cars/ accessed 19/5/2020
- Szymkowski, S., (2019) Following hydrogen facility explosion, fuel-cell vehicle owners left stranded. CNET Roadshow https://www.cnet.com/roadshow/news/hydrogen-fuel-cell-car-california-explosion/ accessed 19/5/2020
- KPIX CBS SF Bay Area Explosion Sets Off Fire at Chemical Plant in Santa Clara Jun2 2019. https://www.youtube.com/watch?v=S8ZAc38piQM accessed 14/6/2020
- The Korean Times. Hydrogen tank explosion kills 2 in Gangrening The Korean Times http://www.koreatimes.co.kr/www/nation/2019/05/281_269400.html accessed 14/6/2020
- Baxter, T., (2020) Hydrogen cars won’t overtake electric vehicles because they’re hampered by the laws of science. The Conversation https://theconversation.com/hydrogen-cars-wont-overtake-electric-vehicles-because-theyre-hampered-by-the-laws-of-science-139899 accessed 4/6/2020
- Tony Seba (2020) on Searching for the Questions Live with David Orban – Rethinking Humanity with Tony Seba STFQL63 https://www.youtube.com/watch?v=mGzrcmDrFfo accessed 14/8/20
- Oil Spills and Disasters Timeline on Infoplease.com https://www.infoplease.com/world/disasters/man-made/oil-spills-and-disasters-timeline accessed 10/8/20
Another way of thinking of this is why not both Battery Electric Vehicles and Hydrogen Fuel Cell Electric Vehicles? I hope one day my family will have one of each. BEV for around town & short trips and a FCEV for around town and long trips.
FCEV’s weigh considerably less than a BEV as a FCEV needs at most 10% of the battery requirements of a BEV, to allow an extra boost of power during high load periods and somewhere to put the regenerative braking power.
Could you imagine the size of the battery pack required to get a loaded B Double accross Sydney? The private sector will build the hydrogen supply system as interstate trucks move away from diesel. There will be no trucking of hydrogen around the country as anywhere there is water and electricity you can put an electrolysis plant including your garage! One day…
Hydrogen gas is not corrosive in any way. It needs to be chemically bonded to Chlorine or Sulphur and Oxygen to be corrosive.
Platinum isn’t to stop corrosion. It is the catalyst.
Platinum is no longer needed for fuel cells anymore anyway.
Can hydrogen compete with batteries? It doesn’t need to as they are complementary, just like diesel and petrol have been for many decades.
Thanks Steven. I guess like all new technologies many are still learning and have some misconceptions – I am clearly no exception and I appreciate your corrections. I had no idea that platinum was no longer needed, which I imagine would cheapen FCEV. I have always thought fuel cells would be necessary for long haul heavy transport but momentum seems glacially slow. With narrow margins in the heavy transport industry there seems little incentive to make the upfront investments to switch. My big concern with hydrogen is whether it will predominantly be produced using renewables and electrolysis and the environmental impacts of this. Or whether the bulk will come from gas and other fossil fuels and the comparative impacts of that.
There is another big issue which has not yet been resolved. Prof. Graeme Pearman of Melb. Uni. , formerly head of CSIRO Atmospheric Physics, has raised concerns about the effect of hydrogen leakage. There is a constant background level of hydrogen in the atmosphere, largely the result of microbial activity in the soil and sea.
His concern is that if this level is increased, it will potentially destroy the ozone layer! (He also suggests that it could also exacerbate the already problematic greenhouse effect of methane in the atmosphere, but didn’t elaborate on the mechanism involved in the report I read).
He is calling for urgency on more research before we head too far down the hydrogen economy path, but particularly for any uses which have potentially large leakage, like transporting and distributing hydrogen as a fuel. It has important and advantageous uses, such as replacing coal for producing steel, but presumably in these situations, the hydrogen would be generated locally and distributed in permanent pipelines with very low leakage.