Energy in Bhutan has been a primary focus of development in the kingdom under its Five-Year Plans. In cooperation with India, Bhutan has undertaken several hydroelectric projects whose output is traded between the countries. Though Bhutan's many hydroelectric plants provide energy far in excess of its needs in the summer, dry winters and increased fuel demand makes the kingdom a marginal net importer of energy from India. Bhutan’s installed power generation capacity is approximately 1.6 gigawatts (GW). Over 99 percent of the country's installed capacity comes from hydropower plants, accounting for 1,614 megawatts (MW) of the country’s total capacity of 1,623 MW in 2018. More than 99.97 percent of households have access to electricity. As of 2011, the Bhutanese government supplied electricity to 60 percent of rural households, a significant increase from about 20 percent in 2003. About 2,500 people use solar power throughout Bhutan. Even where electricity was available for lighting, most rural households cooked by wood fire. Rural homes were often heated with firewood, kerosene, or liquefied petroleum gas. Bhutan has no natural petroleum or natural gas reserves. The kingdom has some 1.3 million tonnes of coal reserves, but extracts only about 1,000 tonnes of coal yearly, entirely for domestic consumption. Bhutan also imports oil at some 1,000 barrels per day. Most oil imports supplied fuel for automobiles. Bhutan remains overall carbon-neutral and a net sink for greenhouse gases. As Bhutan develops and modernizes, however, its domestic demand for energy in household, commercial, and industrial sectors has been steadily increasing. Government agencies and operations Until 2002, Bhutan's energy sector was overseen by the Department of Power under the Ministry of Trade and Industry. In 2002, reforms in the executive body, the Lhengye Zhungtshog, produced three new agencies under the Ministry of Economic Affairs: the Department of Energy, its subsidiary Bhutan Electricity Authority, and the Bhutan Power Corporation. While the Department of Energy formulates policy, planning, and coordination, the Bhutan Electricity Authority is the main regulatory agency of the energy sector. Since 2006, the Electricity Authority has had the ability to impose differential tariff structures on low, medium, and high voltage consumers. Through 2011, the Bhutan Power Corporation remained a publicly held corporation, comprising about 9 percent of the nation's civil service, though its long-term goals included privatization. In December, 2009, Bhutan Power Corporation had 91,770 customers across the country, out of which 47,846 were rural domestic users. It