Historical water mills or places where water mills used to be, are the most suitable places to generate electricity with hydroelectricity. When mechanical work was very expensive water mills proved their worth. Now we are installing them again for generating 100% green energy.

A modern water wheel has a yield of between 65 and 85%. To work out the potential capacity of a location, the type of water wheel, the discharge (the amount of water per second) and the falling height are deciding factors. The gearbox, generator and possible convertor are all highly efficient. Eventually, the complete installation yield is between 60 and 80%. Compare this to wind and sun energy and it is clear that hydro-electricity yields more.

A complete installation costs approximately between 7.000 and 10.000 euros per kW of installed power. Smaller installations are relatively more expensive, bigger ones relatively cheaper. A well designed installation runs for about 7.000 hours with optimal yield. Usually as well as yield for your own use, electricity can also be transported to the public grid.

A well working hydro-electricity installation, with proper maintenance runs for between 30 and 100 years. The amount you earn back depends on the current electricity price. After between seven and fifteen years the hydro-electricity installation begins to earn money.