Hydrogen production and use is expected to grow in 2024, but it remains very expensive to produce and transport, making progress slow. Efforts to decarbonise the global economy reached a milestone at the COP28 climate conference, where there was a concrete pledge to reduce reliance on and make the transition away from fossil fuels. But the potential for renewables is limited in energy-intensive sectors, where very high temperatures and carbohydrates are needed to make products like steel, plastics, pharmaceuticals and fuels for aviation, shipping and trucking. Hydrogen does, on the other hand,…