The obstacles that make hydrogen unattractive for F1’s sustainability push

As the world moves away from fossil fuels to alternative energy sources, hydrogen is often mentioned as a pathway to a low-carbon future. It’s already making its presence felt in motorsport through Extreme H and various sportscar projects, but will it find its way to Formula 1?

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Hydrogen is often thought of as a fuel but in reality it is, like electricity and synthetic fuels, an energy carrier. The difference being that naturally occurring hydrocarbons can be extracted from the earth and burned to release energy with a minimum of processing.

It’s true that the finer cuts of oil need considerable refining but crude oil, like coal or wood, is a naturally occurring fuel. Hydrogen on the other hand, although one of the most abundant molecules on the planet, doesn’t exist in its singular form, preferring to react with other molecules to form compounds. The most common of these is when it combines with oxygen to form water – and it is from water that green hydrogen can be extracted.

We refer to sustainable hydrogen as ‘green’ but unfortunately, at present, less than 1% of available hydrogen is manufactured in a zero-carbon manner. Green hydrogen is made by passing electric current through water in a device known as an electrolyser which splits the water into its constituent parts of hydrogen and oxygen, which are then stored for subsequent use. If the electricity supply comes from a renewable source, then the product can be regarded as carbon neutral.

Most hydrogen is grey hydrogen, obtained by reforming methane gas to split off the hydrogen – but unfortunately allowing the carbon to escape to atmosphere. An interim type of hydrogen production is termed blue. This is manufactured using the same reformers but the escaped carbon is sequestered underground, therefore not adding to atmospheric carbon.

The energy stored in hydrogen can be used in two ways for automotive power. It can either be used to feed a fuel cell or burned in an internal combustion engine (ICE) in a similar fashion to gasoline. The fuel cell is effectively an electrolyser in reverse. It takes hydrogen and mixes it with atmospheric oxygen, generating electricity as it combines the two elements back to produce water.

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Fuel cells have disadvantages when it comes to racing. Firstly, they aren’t particularly efficient, certainly not in the class of battery electric powertrains. This means that if a powerful fuel cell is required then it will also reject a lot of heat. The problem is compounded by the fact that the fuel cell needs to operate at a relatively low temperature – maybe 50 or 60 degrees.

This means that unlike a current Formula 1 power unit, where the water
may run at 130 degrees and the oil at 120, there is a much smaller temperature difference between the fluid being cooled and the ambient air temperature. This then requires fuel cell vehicles to have much larger radiators than internal combustion-engined vehicles. The fuel cell is also rather slow to react to power demands and therefore a battery, albeit a smaller one, is still required to provide instantaneous energy to the electric motors.

Hydrogen can also be used as a fuel in an internal combustion engine and companies as diverse as Toyota and JCB are actively developing this for automotive and off-road use. When used in this way it doesn’t release carbon compounds as products of combustion, although oxides of nitrogen are still produced. However, by running at very lean mixtures the production of NOx is practically eliminated as well as actually making the combustion better controlled.

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The final problem with hydrogen is that it’s the smallest molecule in existence and therefore it has a tendency to work its way through the intermolecular spaces of whatever tries to contain it

Hydrogen also has an advantage in that for a given mass it contains a lot of energy, nearly three times as much as is in gasoline. Unfortunately, while petrol exists as a liquid at atmospheric temperatures and pressures, and therefore can be stored in a simple tank, hydrogen exists as a gas and therefore would require an enormous tank if it were to be stored in this way.

The answer, therefore, is either to cool the gas until it liquifies (which is OK for spacecraft but not suitable for road vehicles), or to compress it to high pressures, which is the route taken by both fuel cell and hydrogen ICE vehicles. In theory, this isn’t a particular problem, other than the tanks need to be extremely robust to withstand the typically 700 bar pressure – but in being robust they’re also heavy and this negates some of the mass advantage the fuel itself has.

The final problem with hydrogen is that it’s the smallest molecule in existence and therefore it has a tendency to work its way through the intermolecular spaces of whatever tries to contain it. In practice, this isn’t a big problem unless you’re leaving your vehicle parked for a very long time (or you’re trying to pipe hydrogen to your central heating system through badly maintained pipes).

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One aspect of this propensity to permeate materials is something called hydrogen embrittlement. This is a real problem
with high-strength steels that are exposed to hydrogen. The hydrogen effectively attacks
the steel, leading to failures at way below the expected stress levels.

So is hydrogen a viable energy source for racing engines? I think the answer is undoubtably yes but is it a better solution than, say, a blend of an advanced sustainable biofuel and e-fuel? That is a more difficult question to answer since much will depend on how the infrastructures for transport fuels develop over the next decade or two.

The production of both green hydrogen and e-fuels must ramp up to provide the economies of scale needed to provide consumers with low-cost energy. In Formula 1 we believe the answer lies in drop-in sustainable synthetic liquid fuels due to their versatility and ease of use. Time will be the judge.

Photo by: Steven Tee / Motorsport Images

Hydrogen technology needs to evolve before F1 considers moving away from its pathway with sustainable fuel