What insanity!!!
They spend more energy to remove the C02 from the air, to make CH4, so they can burn it and return the CO2 to the air.
The net result due to inefficiencies results in more C02 created, than if they used the geothermal directly for electrical power. Because of inefficiencies, the net loss has to be made up with another source of energy to balance out total power for electrical generation.