> Also, you didn't specify a depth for your calculation; won't the flux be higher the deeper you go (i.e. be proportional to the delta-T)? They are talking abou

> Also, you didn't specify a depth for your calculation; won't the flux be higher the deeper you go (i.e. be proportional to the delta-T)? They are talking about going to 20km which as I understand it is WAY deeper than most geothermal systems contemplate. Their whole bet is predicated on the idea that with the gyrotron they can drill deeper since they don't need to mess with high-temp drill bits. The depth doesn't matter at this scale. 20km deep the heat flux is about 0.3% higher. Things get complicated as you go down into the mantle, but at 20km you're still in the top part of the crust. The only thing drilling deep does is increase your max temperature, which increases efficiency, but eventually you hit the same limit as with any other steam generating plant where you can only handle steam that is so hot and so high pressure. With current technology, that limits the efficiency percentage to the low 40s. Maybe with some technological improvements this can go up a bit, but the carnot efficiency of a heat engine where the water is heated to the point it will decompose is 87%, and there is no way you're even going to get near that in a real plant, so increasing efficiency isn't really going to make a huge difference.