*Bei Interesse eine Einschätzung zu H2 in der e-mobility und Ausblick auf den Energiemix (ich arbeite in der Elektronik für e-mob und new energy), Quelle: Lemo Connected, Winter 2023:
Interview mit Prof. Jan van Herle on H2-Mobility (selected parts):
Electric cars have been highly successful, and they don?t emit CO2. So, what?s the use of exploring an alternative solution? This was the naive question addressed to Jan Van Herle, an expert in electrolyses and fuel cells, researcher, and professor at the École polytechnique fédérale de Lausanne (Swiss Federal Institute of Technology Lausanne).
Professor Van Herle, aren?t electric cars sufficient for clean mobility ?
Jan Van Herle : Current electric batteries are not the perfect solution. Their repeated charging and discharging cycles negatively impact their durability. Besides, recharging takes too long, which is not practical for the users. Their weight increases proportionately with the required autonomy and so you quickly reach a limit : it is hardly efficient to embark battery weighing several hundreds of kilos, part of which will never be used. Moreover, lithium resources are limited and will end up lacking. The use of hydrogen would mitigate some of these problems.
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What is the fuel cell/battery proportion ?
Manufacturers adapt the proportion according to their intentions. Typically, it is fifty-fifty. A Hyundai Nexo is an almost purely hydro- gen car : it has a battery, but it is the 5 kg of H2 on board that drives it over 500 km. The solution is still in its early days, is it performing enough ? Over the last few years, research and strong investment in the car industry have contributed to greatly enhancing their performance. We can see the progress for example in their power density ? the kilowatts produced in relation to the cell volume. In the beginning, it was around 0.5 kW/l. Then it reached 1 kW/l. Today, in mass produc- tion, the Toyota Mirai 2 is at 5 kW/l. Some companies have designed cells that provide 8 kW/l. So, cells have become highly compact, and their performance is rather impressive.
How about the price ? A hydrogen car is much more expensive than an electric car... This is probably the main obstacle to their widespread adoption by the public. Some of the materials used in fuel cells are costly. Platinum, used as a catalyser is expensive, but it is used in smaller and smaller quantities. The polymer of the membrane is not cheap either. Bipolar plates are made of graphite, coated steel, or Titan. The latter is expensive. Moreover, it needs to be protected against corrosion in an acid environment. However, all these costs depend on production volumes. Thermal engines, composed of thousands of components, are also costly to start with. But, since they are mass-produced in 70 million copies a year, the price goes down to 50 euros per kW. If the same tendency applies to PEM fuel cells, their price will also drop.
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For example ?
We can?t ? store ? the excess electricity produced by a 2 MW wind tur- bine in the electricity grid, but we can put an electrolyser at the foot of the wind turbine, which will use electricity to produce hydrogen, which can then be stored and used later. We still need to improve the various solutions for storing and transporting H2, which repre- sents a heavy weight in the overall energy balance of this solution. However, scientists and politicians are pushing for large electroly- sis capacities. Gigafactories of electrolysers are being considered to capture green energy and transform it into hydrogen...
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What is required to boost this development even further ? Technological innovation or policy?
Both. A transition of this kind can?t happen without strong politi- cal will. Technologically speaking, nothing is ever finished: the com- bustion engine has been around for 150 years, and billions are still injected every year to improve it... For fuel cells, we need to find ways of reducing the use of platinum. Because it?s expensive, limited, polluting to extract and fragile to source (90% in South Africa, with Russia in the second place...).
In conclusion, what is your vision of the future of hydrogen-pow- ered vehicles ? Will they become dominant ?
No, they won?t. They will coexist with various complementary solutions. Electric batteries seem to be the best solution for light vehicles - bicycles, motorbikes, cars, etc. Fuel cells for heavier vehicles - com- mercial vehicles, lorries, boats, trains, etc. For very heavy vehicles and for covering large distances (crossing an ocean, etc.), fuel cells pose a storage problem, so liquid fuels will be used because their energy density is better. Ammonia and methanol are being considered, and we need hydrogen to produce them! Green mobility will need all these technologies.
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