(Electric energy use per year * 1 year) / (Area * 100 mW/m^2 * 60% thermal to electric conversion efficiency) In reality electricity capacity needs to meet pea

(Electric energy use per year * 1 year) / (Area * 100 mW/m^2 * 60% thermal to electric conversion efficiency) In reality electricity capacity needs to meet peak demand, not average demand, the heat flux in continental crust is more like 65 mW/m^2, and the thermal to electric conversion efficiency is going to be closer to 40%, so the situation is actually much worse for geothermal, but maybe with the right technological developments and implementation you could get better performance.