A power plant, also known as a power station, is a factory that converts all kinds of primary energy stored in nature into electric energy (secondary energy). At the end of the 19th century, as the demand for electricity grew, people began to put forward the idea of building electricity production centers. With the development of motor manufacturing technology, the expansion of electric energy application and the rapid growth of the demand for electricity, power plants emerge as The Times require. Power plants generate electricity in many ways: coal-fired power plants, hydroelectric power plants, solar (photovoltaic) and wind and tidal power plants. Nuclear power plants powered by nuclear fuel are playing an increasingly important role in many countries around the world.
Classification of editing
Hydroelectric power plant
A plant that uses the kinetic and potential energy of water to produce electricity. The amount of water flow and the height of water head determine the amount of water flow energy. From the point of view of energy conversion, the process is as follows: water energy → mechanical energy → electric energy. The production method to realize this energy conversion is to build a dam at the upper reaches of a river to raise the water level and cause a higher water head. Build hydraulic facilities to efficiently capture concentrated water flow. The water is introduced into the turbine of the hydropower plant through the channel of the water diversion machine, and the water energy is converted into the rotating mechanical energy of the turbine. A generator directly connected to the turbine converts mechanical energy into electricity, which is pumped into the grid by the power plant’s electrical system.
When building powerful hydroelectric plants, consideration should be given to improved navigation and land irrigation as well as ecological balance. Hydropower plants are classified into diversion type, dam type and hybrid type according to their structure and hydropower development mode. According to the power plant performance and flow regulation degree, there are runoff type and reservoir type hydropower plants. According to the layout position of power plant plant, there are dam behind type and dam inside type hydropower plants; According to the main engine layout, there are ground type and underground type hydropower stations.
The construction cost of hydropower plant is high, and the power generation is limited by hydrological and meteorological conditions, but the power cost is low, and it has comprehensive benefits of water conservancy. It only takes a few minutes for the turbine to take full load from start-up, and it can adapt to the load change of the power system. Therefore, the hydraulic power plant can serve as the system frequency regulation, peak regulation and load backup.
Small hydropower
In terms of capacity, it is at the end of all hydropower stations, which generally refers to those with a capacity of less than 50,000 kilowatts. The proportion of small hydropower in the world’s total hydropower is roughly 5 to 6 percent. China’s exploitable small hydropower resources are 70 million kW, accounting for about half of the world’s total. Moreover, China’s small hydropower resources are widely distributed, especially in the rural areas and remote mountainous area, suited to local conditions the development and utilization, can develop the local economy to solve the local people’s electricity and difficult problems, and brings considerable benefits to investors return, has a great development prospect, it will become the 21st century first 20 years of development.
In the world, many developing countries have formulated a series of policies to encourage private enterprises to invest in small hydropower. Small hydropower stations have low investment, low risk, stable benefit and low operating cost. Encouraged by various preferential policies in China, a surge of investment in the construction of small hydropower stations has been set off throughout the country. Due to the serious shortage of electricity in the country, private investment in small hydropower stations has mushroomed quietly. The state’s general policy of encouraging rational development and utilization of small hydropower resources has been determined, and since 2003, large hydropower investment projects have also been opened to private investment. According to the 11th Five-Year Plan and the 2015 development plan of The State Council and the Ministry of Water Resources, more preferential policies will be given to private investment in small hydropower and its development. The exploitable amount of small hydropower in China accounts for 23% of the country’s exploitable hydropower resources, ranking first in the world.
Thermal power plant
A plant that produces electricity using combustible materials as fuel. From the point of view of energy conversion, its basic process is: chemical energy → heat energy → mechanical energy → electric energy. Most of the world’s coal-fired power plants are based on coal. The pulverized coal and air are suspended in the boiler chamber of the power plant and intensely mixed and oxidized. The chemical energy of the fuel is converted into heat energy. The heat energy is transferred to the high-pressure water medium in the boiler by means of radiation and thermal convection, and the process of preheating, vaporization and overheating of water is completed in stages, so that the water becomes the superheated water vapor of high pressure and high temperature. The steam is fed to the steam turbine by pipe in a controlled way, and the steam energy is converted into rotating mechanical energy by the steam turbine. The turbine rotor, which spins at high speed, uses a coupling to drag a generator to generate electricity that is pumped into the grid by the plant’s electrical system. [3]
Garbage power plant
Garbage power generation as a kind of thermal power, by the end of 2007, China’s total number of garbage incineration power plant has reached 75, which build up 50, 25 under construction waste incineration plant yield stability and low operating costs and enjoy certain preferential tax policies, can give investors with stable income, but the garbage power generation of the environmental problems cannot be ignored.
Nuclear power plant
Plants that use nuclear energy to produce electricity are also called nuclear power plants. The nuclei (neutrons and protons) of an atomic nucleus have strong binding forces. When heavy nuclear fission and light nuclear polymerization, both will release huge energy, called nuclear energy. The relatively mature technology and large-scale operation are only atomic energy power plants that produce electric energy from nuclear energy released by heavy nuclear fission. From the perspective of energy conversion, it is a conversion process from heavy nuclear fission nuclear energy → heat energy → mechanical energy → electric energy.
Solar power plant
A solar farm is a factory that generates electricity from the sun, a renewable source of energy. It works using photoelectric technology that converts solar energy into electricity. Germany is the world leader in solar power generation, with enough power to power 550,000 homes.
Wind power plant
By the end of 2003, 40 wind farms had been built in 14 provinces (autonomous regions) rich in wind energy resources, with a total capacity of 567.02MW of wind power generating units in operation.
Geothermal power plant
Geothermal energy refers to the renewable energy stored in the Earth’s interior, generally concentrated around the edges of tectonic plates, resulting from the earth’s molten magma and radioactive decay. The global geothermal energy reserves and potential resources are huge, and the annual heat transfer from the earth’s interior to the surface is equivalent to 100PW·h. However, the distribution of geothermal energy is relatively scattered, so it is very difficult to develop. Because geothermal energy is stored underground, it is not affected by any weather conditions, and geothermal has all the characteristics of other renewable energy sources. It can be used at any time, without harmful substances. The key is whether more advanced technology can be developed. Geothermal energy is widely used in many parts of the world and the development technology is improving day by day. For the use of geothermal energy, including low temperature geothermal resources are used in bath and space heating and greenhouse heating, heat pump, and some heat treatment process, at the same time, also can use dry superheated steam and hot water to generate electricity, electricity generation by using moderate temperature water through the shuangliu systemic power generation equipment, etc., the geothermal energy development and application of technology has gradually matured, The research on the effective methods of extracting geothermal energy from dry rocks and from geothermal pressurized resources and magma resources can further improve the application potential of geothermal energy, but the exploration and extraction technology of geothermal energy needs to be improved.
Space power plant
The space power plant could be the largest orbiting structure ever built. If completed, it would cover six square kilometers and be deployed at an altitude of 36,000 kilometers. The man-made structures are so large that they are even visible to the naked eye. The researchers say that from the ground the orbiting power station looks like a star high in the sky. The advantages of moving a solar farm into space are obvious: the power output is not affected by day and night, and the weather is not a concern: there are no clouds to block the power plant’s ability to capture sunlight. What’s more, space power plants don’t take up land resources.
Of course, there are major problems to overcome in building an orbiting power station, such as how to transmit the energy to Earth, using microwaves or lasers. The Japanese scientists’ solution is to use microwaves to transmit energy remotely to the ground. But the orbiting power station will weigh 10, 000 tons. NASA is working on a super rocket that can lift only 120 tons into orbit at a time. The installation of solar panels is also a problem, and they need to be replaced regularly, which involves a huge amount of money.
At present, the power system plays a leading role in the thermal power, hydraulic power, nuclear power plants.