This stinks of hollywood accounting, like a lot of "negative carbon" plans for things that would otherwise be nonsensical for.

The premise here is that if Bitcoin mining uses an energy source that inherently captures carbon or methane, then it's "carbon negative?" This ignores the fact that the energy budget is shared. We could just as well use that same energy for something else currently on carbon-based sources. So, energy is still being wasted on crypto speculation - you've just fudged the total energy budget calculations by pretending it doesn't apply here.