Coal and gas are burned as fuel to produce heat and electricity. In some territories coal and gas are a major source of energy. Other power sources include wood, petroleum, nuclear, and hydroelectrics. Imports depend on the demand for power, and the availability of affordable power sources.
Japan has the largest total of net imports of gas and coal. Belgium has the highest imports when measured per person. When divided equally, US$199 worth of coal and gas is imported (net) for each of the 10.3 million people living in Belgium.