There's also "white" which is naturally occurring pure hydrogen.
Mostly it's seen as being economically infeasible to extract, though there is one working well in the world, and some other potential sources that may be feasible to extract discovered recently.
But the big problem with hydrogen is that right now, the majority of the supply is grey/brown/black, which all emit CO2 to produce. Green is far more expensive, and the carbon capture needed for blue is also expensive and the methods of storage are dodgy.
The thing about green hydrogen is that it's more efficient to transmit and store electricity than convert it to hydrogen and distribute and store that, so it's basically just a worse way of utilizing green energy sources. The only reason hydrogen is at all economical is that grey/brown/black are cheap, and it's hard to see any path for green or blue to become competitive (and truly zero emissions for blue).
It's possible that we'll find reserves of white hydrogen and efficient ways to extract it, but that's purely speculative right now, while building renewable energy sources, electric distribution, and batteries can be done right now.
Mostly it's seen as being economically infeasible to extract, though there is one working well in the world, and some other potential sources that may be feasible to extract discovered recently.
But the big problem with hydrogen is that right now, the majority of the supply is grey/brown/black, which all emit CO2 to produce. Green is far more expensive, and the carbon capture needed for blue is also expensive and the methods of storage are dodgy.
The thing about green hydrogen is that it's more efficient to transmit and store electricity than convert it to hydrogen and distribute and store that, so it's basically just a worse way of utilizing green energy sources. The only reason hydrogen is at all economical is that grey/brown/black are cheap, and it's hard to see any path for green or blue to become competitive (and truly zero emissions for blue).
It's possible that we'll find reserves of white hydrogen and efficient ways to extract it, but that's purely speculative right now, while building renewable energy sources, electric distribution, and batteries can be done right now.