Hydropower

Hydropower is energy derived from flowing water. More than 2,000 years ago, the Ancient Greeks used waterpower to run wheels for grinding grain, today it is among the most cost-effective ways discovered so far to generate electricity. An outstanding 99% of Norway’s electricity needs are met by hydropower. In many countries, micro-hydropower projects are significantly improving lives of many communities, in even the most remote locations.

The basic principle of hydropower is using water to drive turbines. The water’s kinetic energy – or energy of motion – is turned into mechanical energy, which is then turned by a generator into electrical power.

The largest hydropower plant is the 22.5 gigawatt Three Gorges project in China. It produces 80 to 100 terawatt-hours per year, which is equivalent to the yearly demand of 70 to 80 million Chinese households.

Hydropower plants consist of two basic configurations: the first based on dams with reservoirs and the second, run-of-the-river scheme (with no reservoir). Hydropower dams with a large reservoir can store energy over short or long time periods to meet peak demand. The dam scheme can also be sub-divided into small dams with night-and-day regulation, large dams with seasonal storage, and pumped storage reversible plants for both pumping and electricity generation. Small-scale hydropower is normally designed to run in-river, and is considered an environmentally friendly option since it does not significantly interfere with a river’s flow