What Is Primary Energy?

According to the basic form of energy, energy can be divided into primary energy and secondary energy. Primary energy refers to energy resources that exist in their original form in the natural world without conversion and are also called natural energy sources, such as coal, oil, natural gas, and water energy ^[1] .

According to the basic form of energy, energy can be divided into primary energy and secondary energy. Primary energy, that is, natural energy, refers to energy existing in the natural world, such as coal, oil, natural gas, water, etc. ^[1]

Secondary energy refers to energy obtained after processing and conversion of primary energy, including

coal

Coal was buried underground in ancient times due to crustal movement. It evolved over a long period of time in a suitable geological environment. The carbon content is generally 46% to 97%. Coal is an important fuel and raw material for the chemical industry. Coal is abundant in the earth. Coal is produced from the decomposition of organic matter that grows in the swamp or river delta. The coal reserves in the major regions of the world today are the highest in non-Europe, Asia and Oceania, and North America. In other words, it is estimated that the current reserves of coal can be used for 200 years.

Coal is composed of a mixture of organic and inorganic substances. Organic matter in coal is mainly composed of four elements: carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), and some elements constitute inorganic matter in coal, mainly sulfur (S) and phosphorus ( P) and rare elements. In China, coal resources are mainly distributed in Shanxi, Shaanxi, Inner Mongolia, Heilongjiang, Liaoning, and Shandong provinces. Famous large coal mines include Datong Coal Mine, Dongsheng Coal Mine, and Shenfu Coal Mine.

oil

Petroleum is generally considered to be formed by the organic substance "kerogen" in the formation, which is gradually cultivated by the ground temperature for a long period of time and floats in the formation. Due to buoyancy, oil slowly moves upwards along the formation or fault in the water every year until it is blocked by the oil-tight closed formation and stays. As the oil in this enclosure accumulates, the more it accumulates.

Petroleum is second only to coal as a fossil fuel. It is a natural yellow, brown or black flowing or semi-flowing viscous combustible liquid hydrocarbon mixture. Oil is also called "crude oil". It can be processed into various fractions, including natural gas, gasoline, naphtha, kerosene, diesel, lubricating oil, paraffin, and many other derived products. It is the most important liquid fuel and chemical raw material.

natural gas

Natural gas is a kind of hydrocarbon, which is often accompanied by the mining of crude oil in the mining area. In the past, it could not be transported across the ocean, so it could only be used for local use. If natural gas is stored in artificial construction facilities, it will be extremely dangerous if it is damaged by external forces such as earthquakes and fires. If natural gas is stored in artificial construction facilities, it will be extremely dangerous if it is damaged by external forces such as earthquakes and fires.

Natural gas is another important primary energy source besides coal and oil. It has a high calorific value when burning, and has less environmental pollution, and it is also an important chemical raw material. Natural gas is produced similarly to oil, but it is easier to produce than oil.

Natural gas is mainly composed of hydrocarbons such as methane, ethane, propane and butane, of which methane accounts for 80% to 90%. Natural gas can be divided into four types: pure natural gas, petroleum associated gas, condensate gas and mine gas.

Water energy

Hydropower is a widely used primary energy source in nature. It can be easily converted into high-quality secondary energy- electrical energy through hydroelectric power stations. "Hydropower" is both a conventional and widely used renewable energy source. And hydropower has no pollution to the environment, so hydropower is an inexhaustible high-quality energy source among many energy sources in the world.

The use of water resources (commonly referred to as water conservancy development) is to make full and reasonable use of the ground and groundwater sources in river waters in order to obtain the highest comprehensive benefits. Water energy utilization is a systematic project, and its task is to formulate an optimal water resource utilization plan based on the needs of national economic development and water resource conditions, and on the basis of river planning and power system planning. China has vast land, numerous rivers, abundant runoff, and huge drops, and it is rich in hydropower resources. It is estimated that the theoretical reserves of hydropower resources in China's rivers are 676 million kW, and the annual power generation is 590 billion kW · h. Whether it is the theoretical reserves of hydropower resources or the hydropower resources that may be developed, China Both ranked first.

The development method of hydraulic resources is selected according to the centralized drop. There are roughly three basic methods, namely, dyke type, diversion type and mixed type. However, each of these three development methods also needs to be adapted to the natural conditions of certain river sections. Hydropower stations built according to different development methods have very different hub layouts and building compositions. Therefore, hydropower stations are also divided into three basic types: dam type, diversion type and hybrid type.

Solar energy

Solar energy is both primary energy and renewable energy. It is rich in resources, can be used free of charge, and does not require transportation, without any pollution to the environment. But solar energy also has two main disadvantages: one is that the energy density is low; the other is that its intensity cannot be kept constant due to various factors. These two major disadvantages greatly limit the effective use of solar energy.

Humans have a long history of using solar energy. Solar energy utilization mainly includes solar thermal utilization and solar light utilization. Solar thermal applications are widely used, such as solar hot water, heating and cooling; solar drying of agricultural and sideline products, medicinal materials and wood; solar desalination of seawater; solar thermal power generation. The use of solar light is mainly solar photovoltaic power generation and solar hydrogen production.

Wind energy

Sunlight illuminates the atmosphere from top to bottom, heating it up. In addition, due to the rotation and revolution of the earth, uneven heating around the ground causes large air temperature differences to cause air movement. The horizontal flow of air forms wind. Because wind has a certain mass and speed, and a certain temperature, it has energy. About 2% of the light energy radiated from the sun to the earth is converted into wind energy. Nevertheless, the amount of wind energy is still large. It is equivalent to more than 1,000 times the annual global coal consumption energy.

Wind energy has a long history. China is one of the earliest countries in the world to use wind energy. Wind energy is the use of wind turbines to convert wind energy into electrical energy, thermal energy, mechanical energy and other forms of energy, which are used for power generation, water extraction, navigation assistance, refrigeration and heating.

Geothermal Energy

The planet where we humans live is very much like a huge "thermos", it is cool outside and hot inside, and the temperature gets higher as we move inward. People call the thermal energy stored inside the earth "geothermal energy". The earth continuously transports its internal thermal energy source to the ground through volcanic eruptions and hot spring overflows. Modern people often say that hot spring is a kind of geothermal energy that human ancestors began to use long ago. However, it can be said that the large-scale development and utilization of geothermal energy by human beings has just begun. Therefore, geothermal energy is a new energy source with great development potential.

At present, there are more than 120 countries and regions in the world, and more than 7,500 geothermal springs and geothermal wells have been discovered and exploited. The development and utilization of geothermal energy is mainly in the areas of heating, power generation, breeding, greenhouse cultivation and bathing. The use of geothermal energy can be divided into two categories: geothermal power generation and direct utilization.

Ocean Energy

The ocean is a huge treasure trove of energy. Only the kinetic energy of waves, tides and currents in the ocean and the difference in temperature and salinity of the ocean are as high as astronomical. These marine energy sources are inexhaustible and renewable energy sources. Marine energy usually refers to the renewable natural energy contained in the ocean, which is mainly tidal energy, wave energy, ocean current energy (tidal current energy), seawater temperature difference energy, and seawater salt difference energy. More broadly, marine energy also includes wind energy over the ocean, solar energy on the ocean surface, and marine biomass energy. Investigating its cause, tidal energy and tidal energy come from the gravitational changes of the sun and moon to the earth, and the rest from solar radiation.

The amount of ocean energy in the total body of the ocean is huge, but the energy per unit volume, unit area, and unit length is small. That is to say, if you want to get a lot of energy, you have to get it from a lot of seawater. It is renewable. Ocean energy is derived from the gravitational attraction between solar radiant energy and celestial bodies. As long as celestial bodies such as the sun and the moon coexist with the earth, this energy source will be regenerated and inexhaustible.

Bioenergy

Bioenergy is a form of energy that solar energy stores in living organisms in the form of chemical energy. It is a kind of energy that uses biomass as a carrier. It is derived directly or indirectly from photosynthesis of plants. Among various renewable energy sources, biomass Energy is unique, it is stored solar energy, and it is also the only renewable carbon source that can be converted into conventional solid, liquid and gaseous fuels.

Biomass is the fourth largest energy source after coal, oil, and natural gas, and occupies an important position in the entire energy system. Biomass energy has always been one of the most important energy sources for human survival. In terms of energy equivalent, it is the fourth most important energy source after coal, oil and natural gas. In the world s energy consumption, biomass energy accounts for the total 14% of energy consumption, but more than 40% in developing countries.

nuclear energy

Nuclear energy, also called atomic energy, is a highly efficient and durable energy source. Nuclear power generation uses uranium 235's nuclear fission chain reaction to release a large amount of thermal energy, turning water into water vapor, and using these vapors to drive generators to generate electricity. There are many methods of nuclear power generation. In Taiwan, boiling water nuclear power and pressurized water nuclear power are used. In addition to the main application of nuclear power generation, it has many uses in agriculture, medicine, industrial technology, etc. Such as agriculture: use it to keep vegetables and fruits fresh, improve varieties, and prevent diseases and insect pests; in medicine, you can use it to kill cancer cells and treat cancer and other functions. Nuclear power plants have large investment amounts, are time-consuming, and are suitable for construction The site is hard to find. The biggest disadvantage is the disposal and safety of radioactive nuclear waste. The advantages are easier acquisition of nuclear fuel, convenient transportation and storage of raw materials, less demand, and less expenditure on safety stock.

There are two methods for the actual use of nuclear energy: one is the heavy nuclear fission method that has reached the practical stage, which is the principle of nuclear fission reactors; the second is the light nuclear fusion method, which is still in the research and experimental stage, which is the nuclear fusion reaction. principle.