I understand that it may be easier/cheaper to us fossil fuel but hypothetically could hydrogen gas be effective as a fossil fuel replacement for internal Combustion Engines? Would we need to care more of it and or use more of it during the combustion stage?

P.S I'm not using hydrogen gas as a fuel just wanted to know if its possible.

  • 1
    Hydrogen fuel is combined with oxygen in the air to create electricity, powering electric motors. There is no combustion stage with hydrogen fuel. May 31, 2016 at 2:30
  • Hydrogen can be combusted. I have done it myself. Its a very flammable gas. It can make electricity but also can be combusted.
    – LostPecti
    May 31, 2016 at 3:10
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    My mistake. usually when people talk about hydrogen powered vehicles they are referring to hydrogen fueled electric vehicles. You may want to specify your question is about using a traditional internal combustion engine, but replacing gasoline with hydrogen. May 31, 2016 at 4:01
  • No problem. I see where you got your theory. And your right updating now.
    – LostPecti
    May 31, 2016 at 4:06
  • It can and is, in fact there is a but route in London which makes use of hydrogen as a fuel: hydrogenlondon.org/projects/london-hydrogen-bus-project
    – BadAtMaths
    May 31, 2016 at 18:21

5 Answers 5


You can use hydrogen gas, yes. The main problem is that it is not easy to make.

Most hydrogen (about 95% of all hydrogen used today) is produced by partial oxidation of methane and coal gasification, with some from biomass gasification.

A tiny amount is produced by electrolysis of water (but it uses a lot of power to do so)

So, yes, you can use anything that combusts to drive a combustion engine (although it would need to be re-engineered to fit the combustion profile of hydrogen - speed of combustion, temperatures etc are different) but you wouldn't do it this way as it is less efficient than hydrogen fuel cells, and too expensive/difficult.


Hydrogen is an ideal gas to be used for combustion, as there are no harmful emissions byproducts if the combustion (combination of hydrogen and oxygen) is at the proper ratio. You just make pure water, which is fine.

There are several vehicles and several vehicle companies which have explored the concept of pure hydrogen as a combustible fuel.

The engineering challenge consists of how to transport, refuel, and safely carry large amounts of compressed hydrogen in the vehicle "fuel" tank. Someday this may be possible, but it is quite difficult. The Hindenburg disaster has forever made clear the hazards of large amounts of highly flammable hydrogen in a vehicle. (Although that hydrogen was used to create a lighter-than-air vehicle, not INTENDED for combustion.) That was in 1937, and almost 80 years later hydrogen is still just as flammable...


Hydrogen has been used as a fuel in various experiments. The largest-scale experiment I'm aware of is the BMW Hydrogen 7, a 7-series V12 produced from 2005-2007. About 100 were built. This engine could be switched from gasoline to hydrogen.

The difference in fuel consumption is largely due to the different energy density with gasoline (petrol) yielding 34.6 MJ/L and liquid hydrogen yielding 10.1 MJ/L. Based on these energy density figures, one would expect 47.6 L/100 km for hydrogen based on 13.9 L/100 km for gasoline (petrol); which is very close to the stated 50.0 L/100 km.

The big challenge with hydrogen is storing it:

The hydrogen fuel is stored in a large, nearly 170 litre (45 gallon),[6] bi-layered and highly insulated tank that stores the fuel as liquid rather than as compressed gas, which BMW says offers 75% more energy per volume as a liquid than compressed gas at 700 bars of pressure.[7] The hydrogen tank’s insulation is under high vacuum in order to keep heat transfer to the hydrogen to a bare minimum, and is purportedly equivalent to a 17-metre (56 ft) thick wall of polystyrene Styrofoam.[8]

To stay a liquid, hydrogen must be super-cooled and maintained at cryogenic temperatures of, at warmest, −253 °C (−423.4 °F). When not using fuel, the Hydrogen 7’s hydrogen tank starts to warm and the hydrogen starts to vaporize. Once the tank’s internal pressure reaches 87 psi, at roughly 17 hours of non-use, the tank will safely vent the building pressure. Over 10–12 days, it will completely lose the contents of the tank because of this.[9]

The tank is large and heavy, and only a tiny fraction of its weight is fuel:

The hydrogen fuel tank holds roughly 8 kg (18 lb) of hydrogen, enough to travel 201 kilometres (125 mi). The curb weight of the Hydrogen 7 is roughly 250 kilograms (550 lb) heavier than the 760Li...

A third method is storage in a metal hydride. IIRC Mercedes experimented with that in the 1980s, but their fuel tank reportedly cost over $100,000 making it unpractical.

Performance also suffers when running on hydrogen. The conventional BMW V12 develops 327 kW. The hydrogen car was limited to 191 kW.

The car is powered by a 6.0 litre V12 engine capable of running on both premium gasoline and hydrogen fuel. It is rated at 191-kilowatt (260 PS; 256 hp) and 390 N·m (290 lb·ft) of torque using either fuel.[4]


Yes but it would be impractical for Internal combustion engines. Though hydrogen has a very high energy density per kg, producing it, compressing it and storing it just to lose 70% of it's potential energy as heat losses makes little sense. This is why most hydrogen vehicles use fuel cells. Their higher efficiency (up to 60%) combined with the high efficiency of electric motors (up to 92%) is more viable. Even at this point however a diesel engine is still a more competitive option.


Could Hydrogen [gas] Be Used as a Fuel [for motor vehicles]?

Technically - yes. Practically - no.

François Isaac de Rivaz ... invented a hydrogen-powered internal combustion engine with electric ignition and described it in a French patent published in 1807

- Wikipedia

People continued to invent gas powered vehicles, in the second world war there was a brief revival.

enter image description here

The vehicle pictured is using some gas other than hydrogen gas, but you can see the point I'm making.

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