You'd probably have a good shot at running a small steam turbine or steam engine.
A bunch of servo mounted old CDs synchronised to the earth's rotation, all constantly focused on the same point, or other similarly synchronised battery of mirrors, would generate a whole lotta heat indeed. How in blazes could one keep enough power up to run the water pumps for the conjectured turbine, though? Would the energy bled off to run them, while the rest of the system charged a storage battery at the same time it kept the microcontolled servos running, drain the whole system? How big a pump would be necessary to feed enough water to supply such a turbine? How much current would it require? And so on.
The list of problems involved would be the basis for a nice little future homestead power supply, perhaps.