Muscle Power Generators
Why not? This is the most reliable, renewable energy source. Due to their low efficiency these devices were considered frivolous in the past. The topic of “hand turbine power”, as it is called, has become more relevant. They can give your smartphone the missing percentages to make that important call. With the manual option, you only have to turn the handle for a few moments. “Dynamo” is often a component of a powerbank, which most tourists carry with them. We wrote above about portable wind turbines powered by water and wind. You can also unwind the turbines with your hand.
