How green hydrogen could power industries from steel-making to farming
Many industries are eyeing up hydrogen as a source of clean energy, but with supplies of green hydrogen limited, we should prioritise the areas where it could have the most positive impact on carbon emissions, say researchers
Green hydrogen has many possible uses
Bernat Armangue/Associated Press/Alamy
Hydrogen, the most abundant element, gives off energy when combined with oxygen, and the only by-product is water. That is why politicians have touted it as the Swiss Army Knife of climate change, able to power a huge array of vehicles and industrial processes that currently run on fossil fuels.
However, 99 per cent of the hydrogen supply today is “grey” hydrogen, produced by breaking down methane or coal gas, a process that releases carbon dioxide. To reach net-zero emissions, many countries plan to rely instead on “blue” hydrogen, where this CO2 would be captured at the smokestack and injected underground, or “green” hydrogen, which is produced by splitting water with renewable electricity.
Green hydrogen is “an important bet that Western countries should be doing” to compete with China on clean technologies, United Nations chief Antonio Guterres said at a conference on 3 December.
The problem is that low-carbon hydrogen is at least twice as expensive as grey hydrogen. Ramping up production so it gets cheaper will require government subsidies. While places like the European Union are supporting the industry, President Donald Trump has begun to cancel the low-carbon hydrogen hubs planned under a $7 billion programme in the US.
Because of these headwinds, analyst firm BloombergNEF has halved its low-carbon hydrogen production forecast to just 5.5 million tonnes by 2030, roughly 5 per cent of current grey hydrogen consumption. With supply limited, governments and companies should focus only on those clean hydrogen uses that make the most sense for the climate and the economy, experts say.
“Hydrogen can pretty much do everything, but that doesn’t mean it should,” says Russell McKenna at ETH Zurich in Switzerland.
In a recent study, McKenna and his colleagues analysed the CO2 that would have to be emitted to produce and transport low-carbon hydrogen in 2000 planned projects worldwide, comparing this with the CO2 emissions this hydrogen could displace. They found that hydrogen could have the biggest positive climate impact in the steel, biofuels and ammonia industries.
Using hydrogen for road transport, power generation and domestic heating, on the other hand, wouldn’t reduce emissions as much.