Hydropower has been used for generating electricity ever since the end of the nineteenth century, and is now used in 159 countries around the world. Today, it is the most widely used renewable energy source for generating electricity worldwide. At around 3,490 TWh, hydropower accounted for 16 per cent of the world’s electricity generation in 2011. Given rising demand, the proportion of hydropower in the world’s electricity generation is unlikely to increase any further in 2020, though it will total approximately 4,500 TWh.
Base load capability, storage capability, grid stabilisation and decentralisation are hydropower’s strengths, which still holds great potential in the context of the international transformation from conventional energy supply to the increased use of renewables.
Hydropower will play an even greater role as a base load in an energy mix where more electricity will be generated from renewable energy sources. It can contribute to balancing the fluctuations in generation which arise through the use of weather-dependent solar and wind energy, and therefore enable a stable electricity supply from renewable energy sources. Significant investment therefore continues to be made in pump storage technologies. Pumps with a variable speed, in particular, are required to balance out the increasing short-term fluctuations, caused by wind and solar electricity.