Question: how much electricity does a water wheel produce?
Answer: The power in a flow For fixed or towed turbines, the efficiency tends to be quite low. An example of power output is about 100 watts in a flow of 4 metres per second from a rotor diameter of about 30cm. The maximum power in that flow is about (4^3) x 0.5 x 1000 x 0.07 = just over 2000 watts.