<P> Another important factor in reduced electrical demand in recent years has come from the phasing out of incandescent light bulbs and a switch to compact fluorescent and LED lighting . Research by the University of Oxford has shown that the average annual electrical consumption for lighting in a UK home fell from 720 kWh in 1997 to 508 kWh in 2012 . Between 2007 and 2015, the UK's peak electrical demand fell from 61.5 GW to 52.7.GW . </P> <P> While in some ways limited by which powers are devolved, the four countries of the United Kingdom have different energy mixes and ambitions . Scotland currently has a target of 80% of electricity from renewables by 2020, which was increased from an original ambition of 50% by 2020 after it exceeded its interim target of 31 per cent by 2011 . It has a quarter of the EU's estimated offshore wind potential, and is at the forefront of testing various marine energy systems . </P> <P> Britain's fleet of operational reactors consists of 14 advanced gas - cooled reactors on six discrete sites, along with two Magnox units at Wylfa, and one PWR unit at Sizewell B. Overall, the installed nuclear capacity in the United Kingdom is between 10 and 11 GW . In addition, the UK experimented with Fast Breeder reactor technologies at Dounreay in Scotland, however the last fast breeder (with 250MWe of capacity) was shut down in 1994 . </P> <P> While nuclear power does not produce significant carbon dioxide in generation (though the construction, mining, waste handling and disposal, and decommissioning do generate some carbon emissions), it raises other environmental and security concerns . Despite this, it has enormous potential for generating electricity, when it is taken into consideration that uranium could last up to a hundred years . However, even with changes to the planning system to speed applications, there are doubts over whether the necessary timescale could be met, and over the financial viability of nuclear power with present oil and gas prices . With no nuclear plants having been constructed since Sizewell B in 1995, there are also likely to be capacity issues within the native nuclear industry . The existing privatised nuclear supplier, British Energy, had been in financial trouble in 2004 . </P>

Where does the uk get its power from