Seems to me that the methane burning heat pump is fascinating, seems like it’s not the only solution you need though. If standard heat pumps can achieve a similar overall thermodynamic performance using grid energy, and assuming capacity will keep being added to the grid, then you may be at wash with a methane grid vs. methane heat pump. The difference is a methane grid can transition to more renewables over time but a methane heat pump can’t.
Canary just published data showing COPs fairly often stay well above 1.5 even down to sub zero temps. https://www.canarymedia.com/articles/heat-pumps/heat-pumps-outperform-boilers-and-furnaces-even-in-the-cold
Seems to me that the methane burning heat pump is fascinating, seems like it’s not the only solution you need though. If standard heat pumps can achieve a similar overall thermodynamic performance using grid energy, and assuming capacity will keep being added to the grid, then you may be at wash with a methane grid vs. methane heat pump. The difference is a methane grid can transition to more renewables over time but a methane heat pump can’t.