Wooden water wheels operating on the Yellow River in the city of Lanzhou, China. With diameters ranging from 10 to 20 metres, they are used to pump irrigation water.

Mankind has been using water, as well as its energy, for a very long time. Water can be drunk, it sustains fish that can be eaten, one can wash in it and bathing can be very relaxing. These are obvious uses but very early on people realized that water can also be harnessed as a source of energy. The first machines to use energy from water were simple water wheels which helped with some of the heavy work.

The earliest known water-powered machines date back to the last centuries BC and were used by ancient civilisations including the Greeks, Romans and Chinese. In those times, water energy was used mainly for grinding grain and raising water for irrigation. With time, water energy started driving sawmills, trip hammers and various other machines. Finally, people started using it to power electric generators. The use of water energy became much more efficient with the invention of the water turbine. As the turbines were connected to dynamos, the first hydroelectric power plants came about.

14 pictures

14 pictures