The ancient plants buried underground gradually formed solid combustible minerals through complex biochemical and physical and chemical changes.

Coal is considered as black gold and industrial food. Since18th century, it has been one of the main energy sources used in the human world. Since the 2 1 century, although the value of coal is not as good as before, it is still one of the indispensable energy sources for our human production and life for a long time to come. The supply of coal is also related to the stability of China industry and even the whole society. Coal supply security is also the top priority of China's energy security.

Second, oil.

A naturally occurring mixture of gaseous, liquid and solid hydrocarbons. Petroleum is divided into crude oil, natural gas, natural gas liquid and natural tar, but it is customary to use "oil" as the definition of "crude oil".

Petroleum is a thick dark brown liquid, which is called "industrial blood". There are oil reserves in some parts of the upper crust. The main components are mixtures of alkanes, cycloalkanes and aromatic hydrocarbons. It is one of the main targets of geological exploration.

Third, natural gas.

All natural gas in nature includes gases formed by various natural processes in the atmosphere, hydrosphere and lithosphere (including oilfield gas, gas field gas, mud volcano gas, coalbed methane and biogas, etc.). ).

The commonly used definition of "natural gas" for a long time is a narrow definition from the perspective of energy, which refers to the mixture of hydrocarbon and non-hydrocarbon gases naturally contained in the stratum. In petroleum geology, it usually refers to oilfield gas and gas field gas. Its composition is mainly hydrocarbons and contains non-hydrocarbon gases.

Fourth, water.

Inorganic substances composed of hydrogen and oxygen are nontoxic and drinkable. At normal temperature and pressure, it is a colorless and odorless transparent liquid, which is called the source of human life. Water is one of the most common substances on the earth, an important resource for all life, including inorganic compounds and human beings, and the most important component of organisms.

Extended data

First, disposable energy

Coal, oil and natural gas have been formed in the earth's crust for millions of years and cannot be regenerated in the short term.

Second, renewable energy.

Gezhouba Hydropower Station, Three Gorges Hydropower Station and other hydropower stations will not stop generating electricity as long as the Yangtze River water does not dry up.

Baidu encyclopedia-coal

Baidu encyclopedia-petroleum

Baidu encyclopedia-natural gas

Baidu encyclopedia-water

Baidu encyclopedia-conventional energy