Peak output doesn't matter: you cannot get more energy out of rain than rain has. You could build a turbine that can theoretically generate 10MW at its max spee

Peak output doesn't matter: you cannot get more energy out of rain than rain has. You could build a turbine that can theoretically generate 10MW at its max speed, but if it's being pushed by ants, who cares what its max theoretical output is? Look at the top comment of this thread. Even at 100% efficiency, there is nowhere near 200 W/m^2 of energy to possibly extract from rain. Four orders of magnitude less.