Norway is the sixth largest producer of hydropower in the world. The Norwegian hydropower sector has been designed to accommodate variation in the natural supply of water to the power stations and to match production to seasonal changes in demand. A number of reservoirs can store water from surplus wet years for use in years with low precipitation, which facilitates coordination with countries utilizing electricity generated from thermal power systems. Power trade between Norway and other countries takes place under the auspices of Nordel and Nord Pool - the Nordic power exchange.
Traditionally, increases in the need for electricity have been met by developing new hydropower facilities. In the mid-1990s, however, a government decision was taken to construct two gas power stations. The introduction of gas power in Norway has been a topic of heated debate, and has been met with protests from environmentalists.
Substantial research has also been conducted on nuclear energy, but plans to introduce nuclear power plants were set aside by the Storting (Norwegian national assembly) in 1979.
Electricity for household use in Norway is distributed over a 230 and 400 V low-voltage and a 22 kV high-voltage network that is delivered from a national power grid to a regional grid, and further distributed locally at a much lower voltage. Larger-scale power stations are built with a voltage of 300-420 kV so as to be able to transport power over long distances. The various systems in Norway are linked together through the national grid. This facilitates internal coordination and power trading, and ensures optimal utilization of the individual power station under varying production conditions. Cables laid to neighbouring countries make it possible to conduct similar coordination and power trade activities across national borders.