There are many kinds of energy, and after continuous development and research by human beings, more new energy sources have begun to meet human needs. According to different ways of division, energy can also be divided into different types.
1. Primary energy and secondary energy
According to different basic forms, energy can be divided into primary energy and secondary energy. Primary energy refers to energy resources that exist in nature in a natural form and has not been processed or converted; secondary energy refers to energy products converted from primary energy processing. Primary energy can be either renewable energy (such as hydropower, wind energy and biomass energy) or non-renewable energy (such as coal, oil, natural gas, oil shale, etc.). Among them, coal, oil, natural gas and water are the core of primary energy, and they constitute the foundation of global energy in contemporary society. In addition, renewable energy sources such as solar energy, wind energy, geothermal energy, ocean energy, biomass energy and nuclear energy are also included in the scope of primary energy. Secondary energy is the direct or indirect conversion of primary energy into other types and forms of energy resources, such as electricity, gas, gasoline, diesel, coke, clean coal, laser and biogas.
2. Conventional energy and new energy
According to the current development and utilization conditions, energy can be divided into two types: conventional energy and new energy. So far, it has been widely used by people, and the energy with relatively mature technology is called conventional energy, such as coal, oil, natural gas, water energy and biomass energy. Although solar energy, geothermal energy, wind energy, etc. have been utilized for a long time, the technology for large-scale development is not yet mature and has not been widely used, and it has not received further attention until recently. Nuclear energy, biogas energy, hydrogen energy, laser, ocean energy, shale gas, combustible ice, etc., these energy forms have only been recognized and applied in recent years. And in the use of technology and methods are to be improved and perfected, these forms of energy are called new energy. Compared with conventional energy, different types of new energy have different characteristics. For example, the energy density is low, or the grade is low, or intermittent, or according to the existing technical conditions, the economy of large-scale conversion and utilization is still poor, and it is still in the research and development stage, so it can only be developed and utilized according to local conditions. However, most new energy sources are renewable energy sources, which are rich in resources and widely distributed, and will be one of the main energy sources in the future.
3. Renewable and non-renewable energy
Primary energy is further classified. Any energy that can be continuously replenished or can be regenerated in a short period is called renewable energy, and vice versa is called non-renewable energy. Wind, hydro, ocean, tidal, solar and biomass energy are renewable energy sources, while fossil energy sources such as coal, oil and natural gas are non-renewable energy sources. Geothermal energy is essentially a non-renewable energy source, but the huge reserves from the earth and the small amount of human utilization make it have the nature of renewable energy. The new development of nuclear energy will make the nuclear fuel cycle have the property of proliferation, and the energy produced by nuclear fusion may be 5-10 times higher than that produced by nuclear fission. The most suitable fuel for nuclear fusion, deuterium (tritium), exists in large quantities in seawater, which can be described as "inexhaustible and inexhaustible". In this sense, nuclear energy is also renewable. Renewable energy can be primary energy, secondary energy, new energy, or conventional energy.
With the increasing demand for energy in the global economic and social development, many countries pay more attention to the research and development of renewable energy and new energy. It can be expected that with the continuous progress of human science and technology, people will continue to research and develop more new energy sources to replace existing energy sources to meet the high demand for energy from global economic and social development. At the same time, we also believe that there are many new energy sources on the earth that have not yet been discovered by human beings waiting for us to explore and study. The future energy must be sustainable, renewable, non-polluting advanced energy.
The characteristics and development trend of renewable energy
The International Energy Agency (IEA) defines renewable energy as follows: Renewable energy is energy that originates from natural processes of sustainable recharge. Its various forms are directly or indirectly derived from solar radiation energy, geothermal energy or tidal energy, including solar energy, wind energy, biomass energy, geothermal energy, hydroelectric energy, etc., as well as energy from biofuels and hydrogen derived from renewable sources.
The "Renewable Energy Law of the People's Republic of China" was adopted by the 14th meeting of the Standing Committee of the Tenth National People's Congress on February 28, 2005, and came into force on January 1, 2006. Article 1 states that "renewable energy as used in this law refers to non-fossil energy such as wind energy, solar energy, biomass energy, geothermal energy, and ocean energy."
Compared with fossil energy, renewable energy has the advantages of abundant resources, renewable energy and less environmental pollution, but their development and utilization have the following problems (or one of them): low energy density and relatively scattered;
Solar energy, wind energy, tidal energy, etc. are random and intermittent; at present, the development and utilization of renewable energy is technically difficult, and the economy is still difficult to compare with fossil energy. However, renewable energy will surely play an important role in the long-term life of human beings. Developed countries have made the research and development of renewable energy a strategic priority. China is a country with relatively insufficient fossil energy, and high-quality oil and gas resources are even scarcer. Therefore, energy allocation diversification is the only way to solve China's energy problems, and the research and utilization of new energy and renewable energy is one of the ways to diversify energy allocation.
At present, the renewable energy utilization technology has made great progress and has formed a certain scale all over the world.