The UK had installed electricity generation capacity of 74.0 gigawatts (GW) in 2003. Also in 2003, the UK generated 369.9 billion kilowatthours (Bkwh) of electricity while consuming 346.1 Bkwh. Most electricity generation comes from conventional thermal sources (74 percent), followed by nuclear (23 percent), other renewables (2 percent), and hydroelectricity (1 percent). The UK has a privatized electricity sector, where generators and distributors trade electricity on a wholesale market. The largest power producer in the country is British Energy (BE), which controls most of the nuclear power capacity and generates about 20 percent of the total electricity supply. Other important generating companies include E.ON UK, RWE npower, Scottish and Southern Energy (SSE), and ScottishPower (SP). Twelve regional monopolies control electricity distribution in the UK, most of which are owned by the leading generation companies. NGT owns and operates the national transmission system in England and Wales, whereas SSE and SP operate the grid in Scotland, and Northern Ireland Electricity (NIE), a subsidiary of the Viridian Group, operates the grid in Northern Ireland. The UK has slowly integrated the formally-separate electricity markets of its component parts (England, Northern Ireland, Scotland, and Wales). The British government formed the New Electricity Trading Arrangements (NETA) in 2001 to integrate the electricity markets of England and Wales. In 2005, the British government extended NETA to Scotland as the British Energy Transmission and Trading Arrangements (BETTA). There are plans to eventual incorporate Northern Ireland in to the BETTA. In addition, SP and SSE have increased the transmission capacity between England and Scotland to allow them to sell more electricity to English and Welsh customers.