We don't need the heat for fire. Maybe for comfort though. The moon gets mighty cold at night. Its temperature range is about 80 to 370 Kelvin. You could use t

We don't need the heat for fire. Maybe for comfort though. The moon gets mighty cold at night. Its temperature range is about 80 to 370 Kelvin. You could use the same kit to radiate away some of that intense daytime heat too. Spread it across all of Earth. Now as to solar PV, in principle it might be doable I guess. But I am not able to make the necessary calculations. How large would the crater need to be for 10MW say? Even as a heat engine, you might get useful power out. If you could achieve say 150 - 200 celsius difference between your concentrator and night time temperature of the surrounding rocks. Which rocks serve as both the engine's heat-sink and a relatively comfy foundation for your habitat.