How does a hydrogen car actually work?

A hydrogen car carries a tank of hydrogen gas instead of petrol. Inside the car sits a device called a fuel cell — think of it as a quiet onboard power station. The fuel cell combines hydrogen with oxygen from the air to produce electricity, which drives the wheels. The only by-product is water, which drips out of a small pipe at the back. The experience for the driver is almost identical to a normal petrol car: pull up, fill up in a few minutes, and go. No waiting hours for a battery to charge.

The technology is real and road-tested. The question is not whether it works — it does — but whether it makes economic and practical sense for everyday driving.

The big problem: physics and the missing filling stations

Here is the catch that engineers and environmental groups both point to. When you use renewable electricity to split water into hydrogen (a process called electrolysis — passing a current through water to separate the hydrogen and oxygen atoms), then compress and transport that hydrogen, then convert it back into electricity inside the fuel cell, you end up using roughly five times more renewable electricity per kilometre than a car that simply charges a battery and drives. Studies by transport researchers including Transport & Environment and the ICCT put the hydrogen powertrain’s overall efficiency at around 13–20%, compared with 70–80% for a battery-electric car. That gap translates directly into cost: hydrogen fuel is expensive, partly because so much energy is spent making and moving it.

On top of that, public hydrogen filling stations are rare. You can drive for hundreds of miles in most countries without passing one. Until that network exists, most people cannot rely on a hydrogen car the way they rely on a petrol one. These two obstacles — energy efficiency and infrastructure — explain why hydrogen cars remain a niche product today.

Where hydrogen genuinely makes sense — and a glimpse of what could change the maths

The efficiency argument is strongest for ordinary cars and vans, where batteries work well. It weakens considerably for sectors where batteries cannot realistically do the job: long-haul lorries, deep-sea ships, aircraft, and heavy industry that needs very high temperatures. Those sectors have no good alternative to hydrogen or hydrogen-derived fuels. There is also the matter of the roughly 1.4 billion combustion-engine vehicles already on the road; hydrogen-compatible fuels could give those cars a cleaner life without scrapping them. And the efficiency objection changes entirely if the hydrogen is not made by electrolysis but extracted from the ground — so-called natural or geological hydrogen — because in that case no renewable electricity is consumed to produce it. Belgium launched a geological survey programme in early 2026 specifically to find out whether such natural hydrogen exists beneath its territory, following a promising discovery in France’s Moselle region. If commercially viable natural hydrogen is confirmed anywhere in Europe, the cost and energy equation for hydrogen fuel could look very different.

For now, the honest picture for an ordinary driver is this: a battery-electric car is almost certainly the more efficient and cheaper choice for daily commuting. Hydrogen shines where batteries cannot reach — and that is still a very large part of our energy system.

Sources

• New material developed at Oregon State provides boost to carbon capture technologies
• Future of Carbon Capture Technology Market (2026-2035)

Featured image via Unsplash.