So you’ve probably heard of grey, blue and green hydrogen – I won’t explain here, if you haven’t then google it and then come back. But as of the last few days, you may also have heard of ‘white’ hydrogen (also sometimes called ‘gold’ hydrogen). I first came across the idea earlier this year, and I’ve been meaning to write about it, but this week it hit the mainstream with a piece in the Telegraph.
White hydrogen is hydrogen that forms naturally in the rocks under our feet, like oil (although by a different process, and in different rocks). And some reliable sources (like the US Geological Survey) have estimated that there may be a lot more of it than anyone had previously guessed – enough to entirely replace the fossil fuel industry with hydrogen that we can extract at about the same cost as those same fossil fuels.
If you’re like me, and most other commentators, your immediate reaction is, that sounds too good to be true, because surely we couldn’t have missed something that big? Right? Well, I’ve linked to some other sources below, but to summarise:
- People have noticed seepages of hydrogen from rocks all over the world for a long time. The same was true of oil for hundreds of years before anyone thought of developing it.
- Hydrogen forms in completely different rocks to oil, so we haven’t looked in the right places at all.
- People prospecting for oil (and other things) just haven’t been testing for hydrogen.
So, it is possible that vast reservoirs of naturally occurring hydrogen exist under our feet and haven’t been found. Surprisingly little of the earth has been comprehensively geologically mapped.
One key thing about white hydrogen is that it is continuously being formed, mainly by water reacting with certain types of rock. That means that if/when a reservoir is tapped, it may well keep producing forever, as unlike oil the hydrogen is continuously replenished. In fact there is the tantalising prospect of a win-win-win – pumping water and carbon dioxide down a hydrogen well, where the CO2 reacts to form rock, some of the water creates fresh hydrogen, and the rest of the water is heated. The heated water and hydrogen then circulate back up, providing geothermal and hydrogen energy.
Of course it’s impossible to know at this point how much H2 might be economically recoverable, and how long this industry might take to develop. But there is the chance it could happen quite quickly – after all, we have a load of highly capitalised global companies specialised in this type of thing, that we’re currently telling to abandon their primary product.
What would be the implications is we could suddenly produce as much hydrogen as we could use, at a cost per unit of energy comparable to oil? A major worry is that even considering that question might lead to a stalling of current efforts to decarbonise using existing technology. However, I think that’s unlikely – even if we find huge amounts of white hydrogen, it will still mainly dovetail with wider efforts at electrification, we’ll just have more fuel cells and fewer batteries.
The fuel cell industry will be a massive winner, as the economics of fuel cells vs bigger batteries will win out for more vehicles. Efforts to decarbonise current industry with hydrogen will get a huge boost – primarily fertiliser, but also steel and chemicals. And it will make decarbonising shipping with ammonia as a fuel far more attractive. Electrolysis may be a big loser, but then again maybe not – hydrogen will still be hard to transport, and if the use of hydrogen becomes far more widespread, then there may well be interest in producing it by electrolysis in locations further from hydrogen wells.
Then of course we have to consider the possibility of leaks, and whether hydrogen is itself a pollutant? Hydrogen is not itself a greenhouse gas, and it doesn’t last long in the atmosphere, but it does increase climate heating by prolonging the life of methane in the atmosphere, and its effects on ozone. However, some useful work has been done on this by the UK government, which concluded that since some hydrogen is created by the burning of fossil fuels anyway, the amount likely to leak in a hydrogen economy would be less than the reduction in hydrogen from the fossil fuels we would have burned instead. Still, leaks would need to be closely regulated from day one if drilling for hydrogen takes off.
Overall, this may sound a little far fetched, but I think it’s something that everyone in the transport and energy space needs to keep a close eye on. It’s just possible that ten years from now the energy economy could look very different from any of the current predictions.
