If you use it as a charger, please connect a diode in series to one end of the output line. If you use it as lighting, it only needs a drive motor to rotate.
The driving method can be tap water, bicycle, hand wind, etc. Wait. I suggest you use tap water. Simply pull out the tap water holes in the fan blades. If you manage to package it, buy some heat capacity glue and make a glue. a box to surround the water flow. It will be perfect.
Yes, if there is a power cut, we will indeed no longer have any water to drink. Because if there is no electricity, the water pumps of the water plant will not supply electricity to the water in the pipe network and the water will be stationary in the pipe network . However, the water plant has water storage and there is a certain amount of water stored in the basin clir from the water plant, but this water cannot be used by users because there is no power supply for the water pump. So, whether or not there is water storage, if there is no electricity, we will still not have running water to drink.