Oil is the most important fuel, accounting for 40% of primary energy in OECD countries, followed by gas (22%), coal (20%), nuclear energy (11%), and renewable sources including hydropower, biomass and waste (7 %) (2005 figures from RISO, 2008). Unlike most new renewable sources, in developed countries wind turbines are increasingly competitive with conventional power production. Analysis from the Danish Energy Association, for instance, estimates that offshore wind turbines will be competitive with other energy technologies in 2015 (RISO, 2008).