That looks like carbon capture to me, with the difference being whether you bury the carbon / methane (inject underground into previous wells for instance), or whether you use it in a (short!) carbon lifecycle (by say burning it in the winter, and then recapturing it next summer). So its carbon neutral in an active lifecycle, and its carbon negative when the captured carbon is buried. Carbon capture either way. And given that burial of carbon is kind of "easy" (I don't actually know), whatever the form the captured carbon is in, then this sort of usable energy storage carbon capture looks like the best path to making this economical. If the captured carbon itself has some economic value (energy storage), then the odds that we do a lot of it with a lot of excess power is high. The part we don't need gets reburied (and left), and the part we do need is stored and later burned. Doing a lot of it (instead of demonstrating we can do it in a lab) is what strikes me as important. Even if we burn every drop we make.