Norway is a heavy producer of renewable energy, first of all due to good resources in hydropower. Over 99% of the electricity production in mainland Norway is covered by hydropower plants. The total production of electricity from hydropower plants amounted to 135.3 TWh in 2007[1] There is also a large potential in wind power, offshore wind power[2] and wave power, as well as production of bio-energy from wood.[3] Norway has limited resources in solar energy, but is one of the worlds largest producers of solar grade silicon and silicon solar cells, much thanks to the activities of Renewable Energy Corporation.