If you’re an active follower of climate matters, you may have come across debates around hydrogen and its role in a green economy. But you might not have done. It doesn’t come up very often, it gets technical quite quickly, and it has always felt like it’s a few years away. Compared to the column inches commanded by renewable energy or electric cars, hydrogen has always felt theoretical and niche.
That’s no longer the case. The role that hydrogen will play in our future energy system is being determined right now. It needs more scrutiny, and better understanding.
I’ve written plenty of posts about hydrogen over the last few years, but it occurred to me that I’d never really written an explainer. Now would be a good time for that. After all, in Boris Johnson’s ten point plan for decarbonising the economy, hydrogen comes in at number two. It’s a major priority, and last month the government announced a hydrogen strategy aimed at boosting the sector.
So what are we talking about here?
Hydrogen, as you may remember from school, exists in abundance. It’s the most plentiful element in the universe, and nature burns it for energy already. I’m working by its power right now, because the sun burns hydrogen, hundreds of millions of tonnes of it per second.
Despite its ubiquity, hydrogen isn’t readily found in its pure form. It binds with other molecules, with oxygen to form water, or with carbon to create hydrocarbons. So if you want to use hydrogen, you have to crack it apart from its friends. Provided you can capture it and store it safely, you’ve then got a versatile gas that you can use for energy.
There are two important differences between hydrogen and the fossil fuel gas that fills the grid and runs our boilers. First, fossil fuel gases are found, and hydrogen is made. That means you can create it where and when you need it. You don’t need to pump it from under the North Sea or import it from oppressive regimes. And you don’t have to worry about declining global reserves.
Secondly, fossil fuels release greenhouse gases when you burn them, which is destabilising the climate. Hydrogen burns clean.
The possibilities are obvious. Where can we sub in clean hydrogen for those dirty fossil fuels, and knock down those emissions? There are many applications, from heating, to energy storage, to trains and cars and ships, to heavy industry. So the next question is, given how useful it is, where are we going to get enough hydrogen to make a difference?
And that’s where it starts to get complicated. You need energy to make hydrogen, and so how clean it is depends entirely on how it is made.
We’ll come to that next time.