1 Background to hydroelectricity
Water power, or hydropower, became a major ‘modern’ energy source over a hundred years ago, supplying the input for some of the earliest electric power stations. Hydroelectricity has now become a well established technology, delivering in 2014 a little over 16% of the world’s annual electricity; or nearly 4000 terawatt hours (TWh). (IEA, 2016).
This type of power, like most renewable energy sources, is indirect solar power, and has been contributing to local energy supplies for many centuries, for example in the water wheels shown in the figures below.
What hydropower resources are available? You’ll look at that next.