Fuel and energy complex, oil and gas

The fuel and energy complex includes the fuel industry (extraction and processing of oil, gas, coal, peat and shale) and electric power. Energy resources are fuel resources and hydropower (the energy of river water falling from a height). Science is looking for ways to use inexhaustible sources such as solar, wind and geothermal energy widely. To compare fuels, they are converted into conventional fuel: 1 kg of high-quality hard coal with a combustion heat of about 7000 kcal is taken as the unit, and the heat of other fuels is expressed by a coefficient relative to it. Low-heat fuels (peat, shale, brown coal) become expensive if carried far, so they count as local fuel and are used where mined. The most economical fuels are oil and gas: they are cheap to extract and to send by pipeline. The ratio between fuel produced and fuel used is called the fuel-energy balance; today natural gas is the largest part of it.