Norway is a heavy producer of renewable energy because of hydropower. Over 99% of the electricity production in mainland Norway is from hydropower plants. The total production of electricity from hydropower plants amounted to 135.3 TWh in 2007 There is also a large potential in wind power, offshore wind power and wave power, as well as production of bio-energy from wood. Norway has limited resources in solar energy, but is one of the world's largest producers of solar grade silicon and silicon solar cells.
The system for Guarantees of Origin was implemented by the EU Renewable Energy Directive 2009/28/EC. In 2010 the average electricity consumption mix of a Norwegian household was 36% renewable.
As per the European Union's 2009 Renewables Directive (later added in the EEA Agreement), Norway has established a national goal for renewable energy - 67.5% of gross final consumption of energy supplied by renewable sources by 2020.
Norway is Europe's largest producer of hydropower and the 6th largest in the world. The largest producer is the Norwegian government, through the state-owned Statkraft which in turn, owns nine largest hydroelectric plants and is also a major player in the international energy markets. Electricity is also produced by 156 other companies. Hydropower generation capacity is around 31 GW in 2014, when 131 TWh was produced; about 95% of total production. Hydro production can vary 60 TWh between years, depending on amount of precipitation, and the remaining undeveloped hydro potential is about 34 TWh. By 2010 70% of the total potential had already been developed, one of the highest ratios in the world. Dam safety reassessment began in 1995 and by 2014, 26 per cent of existing installations have been rehabilitated or upgraded. Generating capacity in Norway is growing, between 2001 and 2014 there were 397 new projects commissioned, larger than 1 MW. Upgrades to older installations larger than 10 MW represents 70% of all new capacity. Electricity trading with wind power generated in the Netherlands and Denmark is driving modifications to the Norwegian hydro system.