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.

1. What’s hydrogen’s advantage?

Hydrogen flames hot and clean. Replacing the fossil fuels now used in furnaces that reach 1,500 degrees Celsius (2,700 Fahrenheit) with hydrogen could make a big dent in the 20% of global carbon dioxide emissions that now come from industry. In steelmaking, hydrogen could replace the coal that’s now used not only for heat but as a purifying agent. Hydrogen also removes the oxygen from the iron ore, but the result is water vapor rather than CO2.

2. How is it made?

There’s plenty of hydrogen in the atmosphere around us, but harnessing it for industrial purposes is a different matter. Here are the main techniques for manufacturing it:

  • A way of making green hydrogen is via electrolysis, a process that sends an electric current through water to split hydrogen atoms from oxygen. Using renewable electricity to feed the process is key to harvesting the full benefit of hydrogen. Nowadays, most of the hydrogen used as fuel is derived by splitting it off from molecules of natural gas. But that requires a good deal of energy and also produces carbon dioxide at the same time, making the process decidedly unclean. So switching to electricity generated by renewables is key to harvesting the full benefit of hydrogen.
  • Another technology option for producing hydrogen from renewables is steam reforming of biomethane and biogas, in which high-temperature steam reacts with the methane source, in the presence of a catalyst.
  • There are also other less developed technologies, such as pyrolysis, which heats up natural gas until it generates hydrogen. Carbon is produced as a residue, but in a solid form that’s easier to store without adding to atmospheric emissions.

Smokestack Fumes

Industry accounts for a fifth of the world’s annual CO2 emissions

Source: IEA

3. Who’s doing this?