Wind and solar power are the main focus in the fight against climate change, but there are sources of greenhouse gases they can’t clean up. Manufacturing steel, cement and chemicals has traditionally required fossil fuels, either to burn to create the extreme temperatures needed, or as raw materials and catalysts for chemical reactions. That’s why hydrogen is becoming the new climate bet. It burns far more cleanly than fossil fuels, can stand in for carbon in some reactions and so-called green hydrogen -- gas produced using electricity from renewable sources -- is essentially emissions free. Hydrogen is also seen as a clean solution for fueling cars, trucks and ships and heating buildings. All that involves vast expense and work of creating a new energy industry almost from scratch, and bringing costs down to competitive levels.