Let's say you have a certain amount of water at a height; think a bucket with 3 liters of water in it on a 4 meters tall wall. By letting this water to fall, we'd have an opportunity to convert some of this potential energy into electricity.
By using cheap commercial gadgets, one could achieve this by:
- Hand-cranked generator, using the falling mass of the full bucket to do the cranking (using pulleys to get the right torque). example
- Micro water turbine, letting the water flow from top to bottom, where the turbine would be located. example
There are many options on the market for each strategy. Some are more expensive, some have very specific limitations in terms of working pressure, minimum rpm, etc.
My question is: is there a preferred method between these two from a purely conceptual point of view? Should one of these methods achieve higher efficiency in most cases under similar limitations?