Compared with conventional energy sources, new energy sources include nuclear energy, solar energy, wind energy, biomass energy, hydrogen energy, geothermal energy and tidal energy. The new energy is also relatively clean, and it is almost inexhaustible except for nuclear fission fuel. Because conventional energy sources such as coal, oil and gas have the disadvantages of polluting the environment and being non-renewable, people pay more and more attention to the development and utilization of new energy sources.

(1) nuclear energy technology. There are two kinds of nuclear energy: fission energy and fusion energy. Nuclear fission energy refers to the energy released when the nuclei of heavy elements (such as uranium and thorium) split, which is usually called atomic energy. Nuclear fusion energy refers to the energy released when the nuclei of light elements (such as deuterium and tritium) polymerize. A great deal of heat energy generated by nuclear energy can be used to generate electricity and heat. The biggest advantage of nuclear energy is that it has no air pollution and concentrated production, which can replace coal, oil and natural gas fuels. (1) nuclear fission technology, since the completion of the world's first atomic power station in 1954, more than 400 nuclear power plants have been built in more than 20 countries around the world, accounting for 16% of the global power generation. The first nuclear power plant designed, manufactured and built in China is Zhejiang Qinshan Nuclear Power Plant, with a capacity of 300,000 kilowatts. 1800,000 kW Guangdong Daya Bay Nuclear Power Station was built with imported technology. The difference between nuclear power plants and conventional thermal power plants is that nuclear reactors replace boilers, and nuclear reactors are divided into thermal neutron reactors and fast neutron reactors according to neutrons that cause fission. Thermal neutron reactors are used more because they are easier to control. According to the difference of moderator, coolant and nuclear fuel, thermal neutron reactor includes light water reactor (using light water as moderator and coolant and enriched uranium as fuel, including pressurized water reactor and boiling water reactor), heavy water reactor (moderator and cooling heavy water, using natural uranium as fuel), graphite gas-cooled reactor (graphite moderator, carbon dioxide or helium cooling, using enriched uranium as fuel) and graphite water-cooled reactor (graphite moderator, light water cooling, so as to concentrate). The advantage of fast neutron reactor is that it can make full use of natural uranium resources. Thermal neutron reactors can only use about 2% of natural uranium, while fast neutron value-added reactors can use more than 60%. This type of reactor is still undergoing commercial scale demonstration tests. (2) Nuclear fusion technology is that more than two light nuclei polymerize at extremely high temperature, so it is called thermonuclear reaction. Deuterium, the fusion nuclear fuel, is rich in seawater and almost inexhaustible for human beings. Therefore, all countries in the world attach great importance to it. It can be said that the energy guarantee for the eternal development of mankind in the world is nuclear fusion energy.

(2) Solar energy technology. ① The solar heat utilization technology is relatively mature, including solar water heaters, solar boilers burning steam to generate electricity, solar refrigeration, solar focused high-temperature processing, solar cookers, etc. , widely used in industry and civil; (2) Solar photoelectric conversion technology, which converts light energy into electric energy (direct current) through solar photovoltaic cells, is mainly a photovoltaic cell manufacturing technology. There are many kinds of solar cells, including monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium sulfide and zinc arsenide cells. This power generation technology is the most convenient to use, but the cost of high-power power generation is too high. ③ Photochemical conversion technology, which uses solar photovoltaic cells to electrolyze water to produce hydrogen, which is a very clean fuel.

(3) Wind power technology. Wind energy is a kind of mechanical energy, and wind power generation is a common technology. At present, the world's largest wind turbine is 3200 kW with a diameter of 97.5 meters, which is installed in Hawaii, USA. The total installed capacity of wind power in China is * * * 200,000 kilowatts, and the largest wind generator is 120 kilowatts.

(4) Biomass energy technology. This is a technology that uses organic wastes of animals and plants (such as wood, firewood, feces, etc.). (1) thermochemical conversion technology, which converts wood and other wastes into gas by heating in a gasifier, or converts biomass into gas, tar and charcoal by dry distillation; (2) Biochemical transformation technology, which mainly produces biogas through anaerobic fermentation of biomass such as feces, and the main component of biogas is methane. Biogas technology has been well applied in rural areas of China, and industrial biogas technology has also begun to be applied. ③ Biomass molding technology, which squeezes the dried and crushed biomass into high-density solid fuel.

(5) Hydrogen energy technology. Hydrogen has a high calorific value, and the combustion product is water, which is completely pollution-free. Moreover, the raw material for hydrogen production is mainly water, which is inexhaustible. Therefore, hydrogen energy is a promising clean fuel. (1) hydrogen production technology, including water electrolysis, hydrothermal chemical hydrogen production, water photovoltaic cell decomposition, etc. ; ② Hydrogen storage and transportation technology. There are three ways to store hydrogen, one is compression, the other is low temperature liquefaction, and the third is hydrogen storage metal absorption. (3) There are three ways to utilize hydrogen technology, one is direct combustion as fuel, the other is direct power generation through hydrogen fuel cells, and the third is medium for various energy conversion.

(6) Geothermal energy technology. Geothermal energy can be divided into steam and hot water. Geothermal steam has high pressure and temperature, and can be directly used to generate electricity through steam turbines. Geothermal hot water is best used in a cascade way. First, high-temperature geothermal water is used for high-temperature purposes, then the used medium-temperature geothermal water is used for medium-temperature purposes, then the used low-temperature geothermal water is reused, and finally it is used for fish farming, swimming pools, etc. (table 13-6).

(7) Tidal energy technology. Tidal power generation technology is a low-head hydropower generation technology with small capacity and high cost. China's coastline is as long as 14000 km, and it is rich in tidal energy. It is estimated that the installed capacity of tidal power generation that can be developed and utilized in China is 28 million kilowatts, and the annual power generation is 70 billion kWh.