What is tidal power generation like?

The never-ending fluctuation of sea water contains great energy. Can we make full use of the enormous energy of the tides? This is a problem that people have been considering since ancient times. 1000 years, the working people in China have made great contributions to the study of tidal utilization.

For example, in Penglai County, Shandong Province, China, people use the water level difference between high tide and low tide to push the grinding of cars and grains. On the Luoyang River bordering Hui 'an County in the northeast of Quanzhou City, Fujian Province, there is a famous ancient stone bridge in China-Luoyang Bridge, which was built from the fifth year of Song Dynasty to the fourth year of Jiayou (1053 ~ 1059). After visiting this well-preserved ancient stone bridge, we will be surprised to ask: How did dozens of tons of Liang Shi get on the pier under the technical conditions more than 900 years ago? To put it simply, skilled craftsmen at that time skillfully used tidal energy. They put Liang Shi on the raft in advance and drove the raft between the two docks at high tide. As the tide rises, Liang Shi rises slowly. When the high tide comes and Liang Shi passes the pier, it doesn't take much effort to align Liang Shi with the pier. At low tide, the big stone beam will be firmly placed on the pier. The tidal range of the spring tide in Quanzhou can reach more than 6 meters, and the huge tide can lift Liang Shi to the sky effortlessly. Today, when people stand on Luoyang Bridge and admire the intelligence of our people, they can't help but feel sorry that the tide can be wasted year after year.

The above is the way of directly using the tide, that is, directly converting the potential energy and kinetic energy contained in the tide into another form of mechanical energy to do work. This way of utilization is inconvenient and overqualified. Therefore, using tidal power generation to convert tidal energy into electric energy is the goal pursued by modern people.

After the generator came out, it provided people with the conditions to use the tide to generate electricity.

Only 30 years after the establishment of the first power plant in the world, that is, 19 12 years, Germany built the world's first tidal power plant using tidal power in Schleswig-Busum, Holstein. Since then, with the increase of energy demand, more and more countries have studied tidal power generation. France, China, Canada, the Soviet Union, the United States, Britain, India, Australia and Argentina are all competing to invest a lot of manpower and material resources.

The energy contained in the tide is really attractive. It is estimated that124 billion kwh can be generated every year if tidal energy on the earth is used.

Tidal power generation is superior to river power generation. It is not affected by weather and drought, nor does it need to occupy cultivated land and move because of the construction of reservoirs. Therefore, tide is the "fourth energy source" after coal, oil and hydropower. River power generation is called "white coal" and tidal power generation is called "blue coal sea".

The principle of tidal power generation is similar to that of hydroelectric power generation. It also uses the power of water to turn potential energy into mechanical energy through a turbine, and then the turbine drives a generator to turn mechanical energy into electrical energy. So, how can we make water strong? The conditions are simple. People build seawalls at suitable estuaries, separating estuaries or bays from the sea, forming reservoirs, and using the fluctuation of water level during tidal fluctuation to obtain potential energy, thus promoting hydro-generator sets to generate electricity.

The methods of tidal power generation are usually classified according to the different ways of building stations and the different directions of operation, which are generally divided into three categories, namely, one-way tidal power generation in a single reservoir-when the tide rises, the gate is opened to let the tide flood into the Bay Reservoir, so that the water level of the reservoir rises with the tide level. When the highest tide level is reached, the sluice gate will be closed immediately to isolate the reservoir water from the sea, so as to prevent the water from the bay reservoir from flowing back to the sea with the ebb tide. When the tide recedes to a certain extent, the water level of the bay reservoir will be higher than the seawater, which forms the condition for the water to flow downwards and has the power to do work. At this time, the gate of the reservoir is opened again, so that the water in the reservoir can push the blades of the turbine to drive the generator to generate electricity, and then flow back to the sea.

This is the oldest form of tidal power generation, and the first tidal power station in the world works like this. For the sea that fluctuates twice a day, this power station can work twice a day to generate electricity 10 ~ 12 hours.

As time goes on, people find that this power generation method does not make full use of the power of water. Because water with a certain gap and flow is too precious for human beings, it is a pity to let it flow away in vain! In this way, people began to develop a new type of hydraulic turbine. After hard exploration, this new type of hydraulic turbine came out. This kind of hydraulic turbine can rotate forward or backward, and with a generator that can rotate forward and backward, it becomes a reversible hydraulic generator set that can run in both directions. In this way, no matter whether the sea is in high tide or low tide, we can use the tide to generate electricity.

This is another two-way single reservoir tidal power generation-two gates are built on both sides of the dam, and the turbine is located in the middle of the four gates. At high tide, open two gates (1 and 4) and close two gates (2 and 3). Seawater impacts the blades of the turbine to drive the generator to generate electricity, and seawater flows into the reservoir. At low tide, two gates 2 and 3 are opened, and two gates 1 4 are closed, and seawater flows to the sea through the turbine to generate electricity. During the flat tide, all four gates are closed and no power is generated.

This kind of power station can generate electricity twice in a tidal fluctuation process, and it uses one reservoir, so it is called single reservoir bidirectional. It can generate electricity 10 ~ 20 hours every day, and the benefit is much better than that of a single reservoir unidirectional tidal power station.

There are also two reservoirs for tidal power generation, and two reservoirs will be built, one high and one low. The water level of the high reservoir is always kept at the high level, and the water level of the low reservoir is always lower than that of the high reservoir, and the hydro-generator runs in one direction. The upper reservoir has an intake sluice and the lower reservoir has a drainage sluice. At high tide, the intake gate opens and the power station starts to work. The water level of the high reservoir rises with the tide level, and the water level of the low reservoir also rises due to the entry of electrified water. At high tide and low tide, the intake sluice is closed. Due to continuous power generation, the water level of the high reservoir begins to drop, and the water level of the low reservoir rises accordingly. The water level of the low reservoir is lowered by opening the sluice on the low reservoir. The power station is still in operation due to the large gap between the high and low reservoirs. When the water level of the high reservoir drops to a certain gap with the tidal level, the gate is closed and the intake gate of the high reservoir is opened. In this way, the reservoir has always maintained a certain gap, and the power station can generate electricity continuously for 24 hours.

However, the site selection of this kind of power station requires high topography and is generally used less.

Although tidal power stations have various forms, they are generally composed of three parts. The first part is the dam, which is used to prevent seawater from forming a reservoir and is the main part of the power station. The length and height of the dam should be determined according to the local geographical conditions and tidal range. Because the tidal range is not very large, the height of dam body is generally lower than that of barrage of river hydropower station; The second part is the water diversion system, which consists of various gates and water diversion channels. Its main function is to cause the gap between the water surface of the reservoir and the sea surface, as well as between the high and low reservoirs, thus promoting the hydro-generator set to generate electricity; The third part is the power generation equipment and transmission lines with hydro-generator set as the main body. The power generation equipment is installed in the underwater part of the dam, which is the heart of the power station. With these three parts, the tidal power station can work.

The development of tidal power generation in the world is unbalanced, among which France, Russia, Britain and Canada have developed rapidly and made some achievements. At present, they have built tidal power stations with an annual power generation of more than 500 million kWh, and are moving towards giant and super-giant tidal power stations. Scientists are designing tidal power stations with an annual output of more than 65.438+0 billion kWh, and this idea will definitely become a reality in the 265.438+0 century.

China's coastline is 18000 km long, and the island coastline is 14000 km long, which contains a lot of tidal energy. Only one province in Zhejiang can develop 22.7 billion kWh of electricity, which is equivalent to the power generation of two Gezhouba hydropower stations! At present, Jiangxia tidal power station has been built, with an installed capacity of 3,000 kilowatts and an annual power generation of more than107,000 kwh. Its completion and use have accumulated rich experience for further development and utilization of tidal energy in China in the future. After investigation, Huangdun Port in Ninghai County has been used as the site of the 10,000 kW tidal test power station. This harbor can install nearly 50,000 kilowatts, and the annual power generation can be above 65.438+300 million kWh.