Splitting methane to get hydrogen and carbon seems like exactly the wrong direction to move. Just because we like the idea of hydrogen fuel?

Interesting to see this on the HN front page. On the subject of methane pyrolysis, it turns out if you look at the Gibbs free energy calculation, about half of the energy of methane combustion is released from the formation of water, and the other half from the formation of carbon dioxide. That suggests that if you can be efficient with conserving the heat of pyrolysis, you can make a methane power plant that starts with a pyrolysis step to separate out the carbon atoms in an oxygen-free environment, and then burn the remaining hydrogen to power the cycle, and the end result would be a zero-emissions natural gas power plant. It would require twice as much gas to run, but if you can find a good value-added use for the carbon, it could potentially still be cost effective.

This would probably be much more efficient than doing pyrolysis to extract the hydrogen for use in electricity generation somewhere else, because you don't lose the substantial stored heat energy in the process of cooling that hydrogen back down.

And I can't help but wonder if fossil fuel companies might suddenly start endorsing aggressive zero-emissions targets if there's a way for this to double the demand for their products, rather than eliminating it.

Monolith was the first mover here, they are making carbon black for Goodyear. Last year they were running into problems meeting targets for a $1B DOE loan, haven't seen if they've managed to get on track.

https://www.wsj.com/business/energy-oil/a-high-profile-clean...

It requires more input energy, but it's been really good to see electrolysis of H2O for hydrogen generation take off. There are honestly industrial/grid scale operations actually starting now (as opposed to being constructed). E.g. Aces Delta in Utah. 220MW of wind/solar as input (i.e. equivalent to power for a medium sized city) As a disclaimer, my wife works on that project, but I think it's incredibly cool regardless.

Pyrolysis is a less energy intensive way to produce hydrogen, and does deserve more attention. But it still requires methane as a feedstock.

Hydrolysis let's use use hydrogen as essentially a fixed loss battery. It's perfectly complimentary to seasonally variable renewables like wind and solar. Batteries have too high of a loss though time for seasonal or multi-year storage. If you can store it (big if... Not everywhere has a salt dome like Delta, UT), hydrogen really is a great solution.

Some back of the envelope calculations from fellows I work with suggested that the waste heat from a single gas turbine exhaust could supply enough H2 for 3 gas turbines - so a CC power plant with 3 gas turbines, 2 with standard HRSGs that use the exhaust gas to run a steam turbine, and the 3rd using the exhaust heat to run a methane pyrolysis process, would be the preferred configuration. Slightly less efficient, but 0 carbon emissions. The biggest issue would be running the plant at varying loads - you would need storage for excess H2 to run more efficiently.