Coal burning accounts for about 40% of the PM 2.5 in Beijing and is also the chief source of nitrogen and sulphur dioxide. Since 2012, the city has been converting coal-fired power stations to burn natural gas and aims to cap annual coal consumption at 20 million tons. In 2011, the city burned 26.3 million tons of coal, 73% of which for heating and power generation and the remainder for industry. Much of the city's air pollutants are emitted by neighboring regions. Coal consumption in neighboring Tianjin is expected to increase from 48 to 63 million tons from 2011 to 2015. Hebei Province burned over 300 million tons of coal in 2011, more than all of Germany, of which only 30% were used for power generation and a considerable portion for steel and cement making. Power plants in the coal-mining regions of Shanxi, Inner Mongolia and Shaanxi, where coal consumption has tripled since 2000, and Shandong also contribute to air pollution in Beijing. Shandong, Shanxi, Hebei and Inner Mongolia, respectively rank from first to fourth, among Chinese provinces by coal consumption. There were four major coal-fired power plants in the city to provide electricity as well as heating during the winter. The first one (Gaojing Thermal Power Plant) was shut down in 2014. Another two were shut in March 2015. The last one (Huaneng Thermal Power Plant) would be shut in 2016. Between 2013 and 2017, the city planned to reduce 13 million tons of coal consumption and cap coal consumption to 15 million tons in 2015.