Reality → Energy → World energy → Fossil fuels
Coal, oil, and natural gas are non-renewable, fast depleting fossil energy resources that nature built from organic matter over tens to hundreds of million years. Population growth and rapid economic development of middle and low-income countries continue to increase the demand, while new reserves are more difficult to find and costlier to develop. In the long-run, exhaustion of reserves and peaking of production are inevitable, but the timing is uncertain [1] . The present (2023) world situation is as follows:
Dramatic increase of coal mining (closely linked with the Industrial Revolution) started in the 19th century, followed by rapid expansion of oil production in the early 20th century and natural gas in the late 20th century. For all fossil fuels, the economically recoverable reserves are difficult to assess due to inconsistent reporting, scarcity of exploration drilling, and debatable recovery rates (see peak oil for an example of uncertain forecasts).
Saudi Arabia exports about 400 million tons of oil (85% crude and 15% products), equivalent to about 75% of its production. China imports about 620 million tons (90% crude and 10% products) from a variety of countries, equivalent to 80% of consumption. While China is by far the largest importer, the US remains the largest consumer with 20% of the world's oil production consumed by 4% of the world's population.
New conventional oil is mainly discovered offshore under increasingly difficult conditions (water depths about 2 km, well depths about 10 km, pressure exceeding 1000 bars, explosion risk, capital cost of drilling platform $3 billion). At higher oil prices, presently untapped heavy oil could become competitive and extend world oil reserves. The country with the largest oil reserves is deemed to be Venezuela with its presently unexploited Orinoco oil sands.
Hard coal (German: Steinkohle) is often listed separately as steam coal (about 85%), which is used almost exclusively for electric power generation, and metallurgical or coking coal (about 15%), which is transformed into coke for use as reducing agent as well as fuel in blast furnaces for steel production. Lignite (German: Braunkohle), geologically younger than hard coal, has only a third of the heat content of hard coal and causes high CO2 emissions. It is almost exclusively used for mine-based power generation (in Germany, lignite still generates one sixth of the country's electric power).
In 2023, Indonesia exported about 60% of its 760 million tons coal production. The exports account for more than a quarter of world coal trade. Major markets are China, India, South Korea, Philippines, and Japan. China imported about 470 million tons, amounting to 10% of its consumption. The largest source is Indonesia, followed by Russia and South Mongolia.
The quoted world coal 'reserves' include all types of coal (see USGS circular for a classification system and the difficulties involved in determining 'reserves'). At the present rate and pattern of production, bituminous coal may last 50 or more years, while much of the lower-grade coal may never be exploited. The largest reserves are ascribed to the United States (260 billion tons, 87% hard coal and 13% lignite).
In 2023, about 55% of the internationally traded gas was transported by pipeline and 45% in liquified form by LNG carriers over long sea routes. The US exported about 200 billion m3 (20% of its production), mainly to Mexico. The EU imported about 510 billion m3 (two thirds by pipeline and one third as LNG). Liquefaction, transport, and re-gasification of LNG cause an energy loss of about 15%.
The lifetime of gas reserves could be shorter if world production is significantly increased to replace coal in electricity generation. The two countries with the largest gas reserves are Russia and Iran, which together harbor 40% of world reserves.