Hydrogen gas
Hydrogen gas (H2) is a fuel that when burned, produces no pollution and no carbon emissions - only water vapor (H2O). Just one problem: There are no natural resources of hydrogen gas.
To make hydrogen gas, you need to use some other energy source.
Production
Electrolysis
Electricity can turn water (H2O) into hydrogen gas (H2) and oxygen gas (O2).
The electricity could come from renewable sources such as solar, wind, or hydro.
Research needed for this page
Can electrolysis be done efficiently on a medium scale, for example using the energy from a rooftop of solar panels?
Are rare minerals needed to make efficient electrolysis machines? If so, which minerals and how much of them; what are the different options?
Can natural-gas infrastructure be retrofitted for hydrogen gas, in general?
From fossil fuels
Currently most hydrogen is produced from natural gas via steam reforming, but this emits just as much CO2 as burning the natural gas itself.
There's another (similar) process called methane cracking which takes in natural gas, and produces hydrogen gas + solid carbon (not CO2). The main problem, currently, is that it's a net loss of energy
CH4 → C + 2 H2 (endothermic: 74.850 kJ/mol)
2 H2 + O2 → 2 H2O (exothermic: 285.820 kJ/mol)
Uses
Most hydrogen gas today is used in making fertilizer.
But in the future it could also be used for:
- powering electric vehicles
- energy storage
- home heating
- cooking (similar to natural-gas stoves)
The general idea would be to use surplus electricity to generate hydrogen gas, and then use it as a fuel later.