The Carbfix facility in Iceland Oksana Baliukeviciene/Alamy We desperately need clean hydrogen for processes that cannot be powered by renewable electricity – and it might be possible to generate vast quantities from rocks deep underground while locking away carbon dioxide at the same time. Researchers at the University of Texas at Austin have shown that this process works for one common rock type in lab studies. They now want to work with companies on field trials. “We hope to demonstrate that we will be able to generate hydrogen economically while sequestering CO2,” says team member Orsolya Gelencsér. It might even be possible to generate geothermal energy at the same time, she says. Burning hydrogen produces only water, so doesn’t cause global warming. Hydrogen could therefore play a major part in achieving net zero, for instance by helping to decarbonise industrial processes such as fertiliser production and steel-making. The problem is that almost all hydrogen is currently made from fossil fuels, meaning lots of CO2 is emitted during its production. One way to avoid these emissions …