Hydrogen might help buses run but it’s not the ultimate fuel of the future Justin Kase zfivez / Alamy

Replacing fossil fuels with hydrogen could help us reduce greenhouse gas emissions from tricky areas such as heavy goods vehicles. But electrifying our energy supply is the best way to green it, and hydrogen only has a secondary – and perhaps temporary – role to play.

So says a report from the Committee on Climate Change, the expert body that advises the UK on how to meet its climate targets.

“Hydrogen gives an option to help us decarbonise those really difficult bits of the energy system that otherwise we would really struggle to do, because we can’t electrify everything,” says David Joffe, one of the authors of the report.


The report is a blow to the UK’s gas industry, which is promoting the idea that the natural gas widely used for heating homes in many countries should entirely be replaced by hydrogen – made from natural gas. The idea is to capture and store the carbon produced by this process.

But many efforts to make carbon-capture-and-storage cheap and practical have foundered. And the report says that even if it could be done it would not eliminate all emissions, and that the resulting gas would be more expensive than natural gas.

Very selectively

Instead, it concludes that hydrogen should be used very selectively, such as for heating only on the coldest days, for some industrial processes and for replacing diesel in large vehicles.

“This report explains that hydrogen is not the silver bullet it is often claimed to be by the gas industry,” says Richard Lowes of the University of Exeter in the UK, who studies energy policy.

In theory, hydrogen could play a very big role in phasing out fossil fuels, as it produces no CO2 when it is burned. The problem is producing it on the scale required.

The cleanest way is to use electricity to split water into hydrogen and oxygen. But electrolysis is expensive and inefficient. If hydrogen made from electrolysis was used for heating homes, say, you would end up with just 62 per cent as much heat energy as the electrical energy you started with.

If electricity is instead used to a drive heat pump, you end up with 280 to 410 per cent more heat energy than the electricity consumed, because heat pumps use the electrical energy to extract the heat energy already present in the air or ground near a building.

Unmanageable

So it would require building an enormous amount of renewable energy capacity by 2050 to produce enough hydrogen by electrolysis to heat homes, says Joffe. “It has unmanageable implications.”

There are some other practical problems with hydrogen, too, the report notes. For instance, it is more likely to leak because the molecules are smaller, and it produces air pollution in the form of nitrous oxides when burned.

Read more: The race to green domestic heating and prevent climate catastrophe