How is energy classified?

The energy family is very large. In order to deeply study, develop and utilize various energy sources, people arrange and combine them according to different classification methods, and "sit in the right place". Classification methods include: according to the formation and source of energy, according to the utilization status, according to whether it is renewable or not, according to the acquisition mode and so on. In addition, energy can also be classified according to the degree of pollution, use, nature of storage and transportation.

According to the impact and pollution degree of energy on the environment, it can be divided into clean energy and non-clean energy. Any energy that has no or little pollution to the environment in use is called clean energy, such as solar energy, hydro energy, wind energy and ocean energy. Any energy that causes or may cause serious pollution to the environment in use is called non-clean energy, such as coal and oil.

It can be divided into fuel energy and non-fuel energy according to its use. Fuel energy includes fossil fuels (such as coal, oil, natural gas, etc. ), biofuels (such as wood, biogas, carbohydrates, organic waste, etc. ), chemical fuels (such as propane, methanol, alcohol, aniline, gunpowder, etc. ) and nuclear fuel (such as uranium, thorium, deuterium, tritium, etc. Non-fuel energy includes hydropower, wind energy, solar energy, ocean energy, geothermal energy, laser and electric energy.

According to the nature of energy storage and transportation, it can be divided into high energy and process energy. All objects containing energy are called potential energy, which can be directly stored and transported by people. All kinds of fuel energy and geothermal energy are high energy sources. Process energy refers to the energy generated in the process of movement, which cannot be directly stored and transported by people, such as wind, running water, ocean currents, tides, waves and other energy sources.