What Are Hydroelectric Generators?

Hydropower, science and technology that studies technical and economic issues such as engineering construction and production operations that convert water energy into electricity. The hydro energy used by hydropower is mainly the potential energy contained in water bodies. In order to convert water energy into electricity, different types of hydropower stations need to be built.

Hydropower, science and technology that studies technical and economic issues such as engineering construction and production operations that convert water energy into electricity. The hydro energy used by hydropower is mainly the potential energy contained in water bodies. In order to convert water energy into electricity, different types of hydropower stations need to be built.

Chinese name

Hydropower

Foreign name

Hydroelectric power

Principle

Converting water to electricity

the way

Hydropower station

Raw materials

River, lake

Classification

Dam-type hydropower plant

Hydropower development

Driven by the strong demand of China's electric power, China's water turbine and auxiliary machinery manufacturing industry has entered a period of rapid development, and its economic scale and technical level have significantly improved. China's water turbine manufacturing technology has reached the world's advanced level.

At present, the comprehensive strength of China's hydraulic turbine and auxiliary machinery manufacturing industry has increased significantly, and the entire industry has shown a booming and vibrant situation. The improvement of the industry is reflected in the improvement of the quality of economic operations and the significant increase in economic benefits. In 2010, there were 68 enterprises in China's hydro turbine and auxiliary machinery manufacturing industry above the designated size (the annual sales revenue was more than 5 million yuan), and realized sales revenue of 4.470 billion yuan, an increase of 2.35% year-on-year. .

At present, energy-saving, environmental protection, and high-efficiency units have become the development direction of power generation equipment products. As an important part of hydropower generation equipment, turbines will also develop in the direction of high power and high parameters in the future. The localization of large-scale mixed-flow hydraulic motors has also driven the technological progress of China's cross-flow turbines and impact turbines, and China's water turbine manufacturing industry has continuously improved its position in the international market.

In 2010, China s hydropower installed capacity reached 211 million kilowatts, with a newly-approved hydropower scale of 13.22 million kilowatts and a construction scale of 77 million kilowatts. According to China's commitment to the international community that "non-petrochemical energy will reach 15% of total energy in 2020", China's hydropower industry must have an installed capacity of 380 million kilowatts in 2020. And even in accordance with the Medium and Long-Term Development Plan for Renewable Energy announced by China, it is determined that the installed hydropower capacity will reach 300 million kilowatts by 2020, and there will be nearly 300 large hydropower units with a single unit capacity of more than 50 kilowatts in China in 11 years, with an average annual Newly installed 25 large hydropower units of 500,000 kilowatts and above. If the installed capacity of 380 million kilowatts is reached in 2020, China's required water turbines and auxiliary equipment will further increase, and China's water turbine and auxiliary machinery industry has a bright future.

Introduction to Hydropower

Hydroelectric power uses rivers, lakes, and other high-potential water flows to a low level to convert the potential energy contained in them into kinetic energy of a hydroturbine, and then uses the hydroturbine as the motive force to drive the generator to generate electricity. Use hydraulic power (with water head) to propel the hydraulic machine (turbine) to turn the water energy into mechanical energy. If another type of machine (generator) is connected to the water turbine, it can generate electricity as the water turbine rotates. For electrical energy. Hydropower is, in a sense, the process by which the potential energy of water is transformed into mechanical energy and then into electrical energy. Due to the low voltage of the power generated by the hydropower plant, if it is to be transmitted to users who are far away, the voltage must be increased through a transformer, and then transmitted from the empty transmission line to the substation in the user concentration area, and finally reduced to suitable for families. The voltage of users and factories' electrical equipment is transmitted to various factories and households through power distribution lines.

Hydropower Principle

The basic principle of hydropower is to use the water level drop and cooperate with the hydro-generator to generate electricity, which is to use water

Three Gorges Dam

The potential energy is converted into the mechanical energy of the water wheel, and then the generator is driven by the mechanical energy to obtain electricity. Scientists use the natural conditions of water level drop to effectively use fluid engineering and mechanical physics, etc., to carefully match to achieve the highest power generation for people to use cheap and pollution-free power.

The low-level water circulates around the earth by absorbing sunlight, thereby restoring high-level water sources.

In 1882, the first place where hydropower was applied was in the state of Wisconsin. Until now, the scale of hydroelectric power has ranged from the small and small tens of watts used in the countryside of the Third World to the millions of watts used for power supply in large cities.

Types of hydropower

According to the method of centralized drop, there are: dam-type hydropower plants, diversion hydropower plants, hybrid hydropower plants, tidal hydropower plants and pumped storage power plants.

Classified by the degree of runoff regulation, there are: unregulated hydropower plants and regulated hydropower plants.

According to the nature of the water source, it is generally called a conventional hydropower station, which uses natural water sources such as rivers and lakes to generate electricity.

According to the size of the water head used by the hydropower station, it can be divided into high water head (more than 70 meters), medium water head (15-70 meters) and low water head (less than 15 meters) hydropower stations.

According to the installed capacity of hydropower stations, it can be divided into large, medium and small hydropower stations. Generally, those with an installed capacity below 5,000kW are called small hydropower stations, those with 5,000 to 100,000kW are called medium-sized hydropower stations, and those with 100,000kW or more are called large hydropower stations or giant hydropower stations.

Hydropower process

The usual process of hydropower generation is: after the water of the river is taken through the water blocking facilities, it is sent to the power plant through waterway facilities such as pressure tunnels and steel pipes. When the unit must run to generate electricity, open the main valve (similar to the function of a faucet in the home) and then open The guide wing (the small water gate that actually controls the output power) makes the water impact the turbine. After the turbine rotates, it drives the generator to rotate. After the generator is excited, the generator establishes a voltage and starts to send power to the power system after the circuit breaker is turned on. If you want to adjust the output of the generator set, you can adjust the opening of the guide wing to increase or decrease the amount of water. The water after power generation is returned to the river channel through the tailwater channel to supply downstream water.

Hydropower advantages

Hydroelectric power

Water energy is an inexhaustible, renewable, clean energy source. But to have

Hydropower

Effective use of natural water energy requires artificial construction of hydraulic structures, such as dams, diversion pipes, and culverts, which can concentrate the flow drop and regulate the flow. Therefore, the project has a large investment and a long construction period. However, hydropower generation has high efficiency, low power generation cost, fast unit startup and easy adjustment. Due to the use of natural water flow, it is greatly affected by natural conditions. Hydropower is often an important part of comprehensive utilization of water resources, and it forms a comprehensive water resource utilization system with shipping, breeding, irrigation, flood control and tourism.

Hydropower

Hydropower is a renewable energy source and has less impact on the environment. In addition to providing cheap electricity, it also has the following advantages: controlling floods, providing irrigation water, and improving river navigation. The related projects also improve transportation, electricity and electricity in the area.

Hydropower

Power supply and economy, especially tourism and aquaculture. The Tennessee River Comprehensive Development Plan in the United States is the first large-scale water conservancy project to drive overall economic development.

Disadvantages of hydropower

General overview of hydropower

1. Too much capacity cannot be built due to terrain restrictions. The single unit capacity is about 300MW.

2. The construction period is long and the construction cost is high.

3 Because it is located in natural rivers or lakes and marshes, it is susceptible to feng shui disasters and affects other water conservancy projects. Power output is susceptible to weather and drought. .

4 It is not easy to increase capacity after the plant is built.

5. Ecological damage: the erosion of water flow below the dam is intensified, the changes of rivers and the impact on animals and plants.

6. Dam construction and resettlement are required, and infrastructure investment is large.

7. The fertile alluvial soil downstream is reduced by erosion.

Ecological impact of hydropower

Huge dams that need to flood a wide range of upstream areas can destroy biodiversity, productive lowlands, forests, wetlands, and grasslands along river valleys. Reservoirs built for hydropower can cause habitat fragmentation and water and soil erosion Deterioration of churn.

Flood large tracts of land for water storage

Hydropower projects affect aquatic ecosystems upstream and downstream of the surrounding area. For example, studies have shown that dams along the North American Atlantic and Pacific coasts reduce the number of salmon populations that need to lay eggs upstream because dams prevent these fish from breeding eggs upstream. Although fish ladders are installed at the largest dams in salmon habitats, this cannot be avoided. Young salmon are also suffering because they must pass through the turbines of the power station as they migrate to the sea. To protect these fish, some parts of the United States transport small salmon by yacht to downstream parts of the year. In special cases, some dams, such as the Marmot Dam, have been demolished due to its impact on fish. How to design a turbine generator with less damage to aquatic life is an active research area. Some mitigation measures, such as fish ladders, have become a necessary condition for the approval of new projects and the approval of existing projects in some countries.

Factors such as the construction of large-scale water conservancy projects in the Yangtze River Basin have severely affected the migratory routes and breeding sites of Chinese sturgeon, causing its population to decrease drastically and threatening extinction.

Environmental impact of hydropower

Environmental Impacts of Water Power Generation Environmental Impacts of Water Power Generation Environmental Impacts of Water Power Generation

I. Geography: Huge reservoirs may cause surface activities and even induce earthquakes. In addition, it will cause hydrological changes in the watershed, such as lower water levels downstream or reduced sediment from upstream. After the completion of the reservoir, due to the large amount of evaporation, the climate is cool and stable, and the rainfall is reduced.

2. Biological aspects: For terrestrial animals, after the completion of the reservoir, a large number of wild animals and plants may be drowned and even extinct. For aquatic animals, after the reservoir is completed, due to changes in the upstream ecological environment, fish will be affected, leading to extinction or reduction in population.

At the same time, due to the expansion of the upstream waters, the habitat of certain organisms (such as Oncomelania snails) has increased, which has created conditions for the spread of some regional diseases (such as schistosomiasis).

3. Physical and chemical properties: The water flowing into and out of the reservoir changes in physical and chemical properties such as color and odor, and the density, temperature, and even solubility of water in each layer of the reservoir are different. The water temperature of the deep water is low, and the organic matter at the bottom of the sedimentary reservoir cannot be fully oxidized and undergoes anaerobic decomposition, and the carbon dioxide content of the water body is significantly increased.

Hydropower classification

According to the nature of the water source, it can be divided into:

Hydropower

Conventional hydropower stations use natural water sources such as rivers and lakes to generate electricity.

Pumped-storage power stations use the excess electricity when the grid load is low, and pump the water from the lower reservoir to the higher place for storage. When the grid load peaks, water is discharged to generate electricity, and the tail water is collected in the lower reservoir.

According to the development of hydropower stations, they can be divided into:

There are three basic types of dam hydropower stations, diversion hydropower stations and hybrid hydropower stations.

According to the size of the water head used by the hydropower station, it can be divided into:

High head (above 70 meters), medium head (15-70 meters) and low head (below 15 meters) hydropower stations.

According to the installed capacity of hydropower stations, it can be divided into:

Large, medium and small hydropower stations. Generally, those with a installed capacity of less than 5,000 kW are small hydropower stations, 5,000 to 100,000 kW are medium-sized hydropower stations, and 100,000 kW or more are large hydropower stations, or giant hydropower stations.

History of Hydropower

In 1878, France built the world's first hydropower station. America

Hydropower schematic diagram

The first hydropower station was built on the Fox River in Appleton, Wisconsin, USA. It consists of two DC generators driven by a waterwheel, with an installed capacity of 25kW. It was generated on September 30, 1882. The first commercial hydropower station in Europe was the Tivoli Hydropower Station in Italy, which was completed in 1885 and has an installed capacity of 65kW. Since the 1890s, hydropower has been valued in many countries in North America and Europe. A number of tens to thousands of kilowatts of hydropower stations have been built using the mountainous rapid rivers, falling water, waterfalls and other excellent terrain locations. In 1895, a 3750kW hydropower station was built at Niagara Falls on the US-Canadian border. Since the beginning of the 20th century, due to the development of long-distance power transmission technology, hydropower resources in remote areas have been gradually developed and used, and power has been supplied to cities and power centers. Since the 1930s, the speed and scale of hydropower construction have developed faster and greater. Thanks to advances in science and technology such as dam construction, machinery, and electricity, it has been possible to repair various types and different sizes of hydropower under very complex natural conditions. Power generation project. The hydropower resources that can be developed around the world are about 2.261 billion kW, which are unevenly distributed, and the degree of development varies from country to country.

China is the country with the richest hydropower resources in the world, and its developable capacity is about 378 million kW. The first hydropower station in mainland China was the Shilongba Hydropower Station (see color picture), which was built on the Mantis River in Yunnan Province (see color picture). . Before the founding of the People's Republic of China in 1949, a total of 42 hydropower stations were completed and partially completed nationwide, with a total installed capacity of 360,000 kW, and the annual power generation was 1.2 billion kW · h (excluding Taiwan). Since 1950, hydropower construction has made great progress, with a single hydropower station installed above 250,000 kW as a large-scale, between 25,000 and 250,000 kW as a medium-sized, and below 25,000 kW as a small, large, medium and small. A number of large-scale backbone hydropower stations. The largest of these is the Three Gorges Dam on the Yangtze River. A number of medium-sized hydropower stations have been built on some rivers, some of which are also connected in cascades. In addition, a large number of small hydropower stations have been built on some small and medium rivers and creeks. By the end of 1987, the country s total installed hydropower capacity was 30.19 million kW (excluding small hydropower stations below 500 kW), and the total installed capacity of small hydropower stations was 11.1 million kW (including small hydropower stations below 500 kW, see Small Hydropower). On August 25, 2010, the largest single-invested project ever in Yunnan ProvinceHuaeng Xiaowan Hydropower Station Unit 4 (installed 700,000 kilowatts) was formally put into operation, generating China s hydropower installed capacity exceeding 200 million kilowatts. As a result, the total installed power generation capacity ranks first in the world.

China is one of the countries with the most abundant hydropower resources in the world. The developable installed capacity of hydropower resources technology is 542 million kilowatts, and the economically developable installed capacity is 402 million kilowatts, with great development potential.

Hydropower Outlook

In some countries (including China) that are rich in water resources and less developed,

Hydropower-customary hydropower process

In the future, in the construction of electric power, priority will be given to developing hydropower according to local conditions. In countries and regions where the level of hydropower development and utilization is already high or water resources are scarce, the expansion and reconstruction of existing hydropower stations is imperative, and pumped storage power stations built in cooperation with the construction of nuclear power stations will increase. In addition to focusing on the construction of large-scale backbone power stations in China, small and medium-sized hydropower stations will receive further attention due to their short construction cycles, quick results, and low impact on the environment. With the reform of the electricity price system, the economic benefits of hydropower can be more appropriately reflected and evaluated, which will help absorb investment and accelerate hydropower construction. In the preliminary work of hydropower construction, new types of surveying technologies such as remote sensing, telemetry, geophysical exploration, and computer and computer-aided design will be developed and popularized. Issues such as floods, sediment, reservoir resettlement, and environmental protection will be handled more appropriately; The automation and telemobilization of hydropower stations will also be further improved and promoted; the development of long-distance, ultra-high voltage, superconducting materials and other transmission technologies will help accelerate the development of the rich hydropower resources in western China and transmit electricity to the eastern coastal areas.

With the implementation of the national energy saving and emission reduction policy, energy substitution emission reduction has become a practical choice for China, and hydropower has become the first choice for renewable energy. At this stage, hydropower companies with cost advantages will enter the fast track of rapid development. Therefore, the outstanding domestic hydropower companies pay more and more attention to the research on the industrial market, especially the in-depth research on the industry development environment and industry buyers. Because of this, a large number of outstanding domestic hydropower companies have risen rapidly and gradually become the leader in China's hydropower industry!

The former world's largest hydroelectric generator runner was processed in the Three Gorges Dam area, and the ship was shipped to the Jinsha River Xiangjiaba Hydropower Station. So far, the Three Gorges Dam area has the ability to process the world's largest hydroelectric turbine runners.

The Xiangjiaba Hydropower Station located downstream of the Jinsha River is the fourth largest power station in the world. The installed single unit capacity of the unit is 812,000 kilowatts, surpassing the Three Gorges to become the world's largest hydropower unit. The runner, which was shipped yesterday, has a maximum diameter of 10.5 meters, a height of 4.7 meters, and a weight of 406 tons. It is the core component of Unit 3 of the Xiangjiaba Power Station. Its size, weight, technical content and manufacturing difficulty are among the highest in the world today. ^[1]

In 2012, the global hydropower generation increased by 4.3, which was higher than the historical average. All the net increase in power generation came from China, accounting for 100% of the global net hydropower annual growth, setting a record for the largest annual increase in a single country in the data sheet. According to domestic statistics: In 2012, the country s new hydropower installed capacity was 15.51 million kilowatts. By the end of 2012, the nation s installed hydropower capacity reached 248.9 million kilowatts (including 20.31 million kilowatts of pumped storage), accounting for 21.7 of the country s installed electricity capacity. An increase of 3.2 percentage points over the previous year. In 2012, the average utilization hours of hydropower generating equipment of 6000 kW and above for the whole year was 3555 hours, a year-on-year increase of 536 hours.
In 2012, China s hydropower consumption reached 194.8 million tons of oil equivalent, an increase of 22.8 from 158.2 million tons of oil equivalent in the previous year (2011); in 2012, China s hydropower consumption was 194.8 million tons of oil equivalent Equivalent, accounting for 23.4 of the global hydropower consumption of 831.1 million tons of oil equivalent, becoming the world's largest hydropower producer / consumer, and the second largest Brazilian producer / consumer of hydropower production / consumption (94.5 million tonnes of oil equivalent) Of 206.

Hydropower technology

Study the science and technology of technical and economic issues such as engineering construction and production operation that convert water energy into electrical energy. The hydro energy used by hydropower is mainly the potential energy contained in water bodies. In order to convert water energy into electricity, different types of hydropower stations need to be built. It is an engineering measure consisting of a series of buildings and equipment. Buildings are mainly used to concentrate the drop of natural water flow to form a water head, and pool and adjust the natural water flow with a reservoir; the basic equipment is a hydro-generator set. When the water flow enters the water turbine through the diversion building of the hydropower station, the water turbine is driven by the water flow to rotate, so that the water energy is converted into mechanical energy; the water turbine drives the generator to generate electricity, the mechanical energy is converted into electrical energy, and then the power is sent to the user through the transformer and transmission and distribution equipment . Water energy is a renewable energy source in the natural world. It is repeatedly regenerated with the hydrological cycle. Water energy and fossil fuel both belong to the resource primary energy, which is called secondary energy after being converted into electricity. Hydropower construction is an electric power construction in which primary energy development and secondary energy production are completed at the same time. No fuel is consumed during operation, and operating management costs and power generation costs are much lower than coal-fired power stations. Hydroelectric power does not undergo chemical changes in the process of converting water energy into electricity, does not excrete harmful substances, and has a small impact on the environment. Therefore, hydropower generates a clean energy source.

Hydropower research content

Hydropower Overview

Hydro generator room

Most of the hydropower stations that have been built in the world are conventional hydropower stations built by utilizing the natural drop and flow of rivers. This type of hydropower station is divided into two types of runoff type and storage type according to the utilization method and regulation capacity of natural water flow; according to the development method, it can be divided into dam type hydropower station, diversion type hydropower station and dam-diversion mixed type hydropower station. Pumped storage power stations are a type of hydropower station that has developed rapidly since the 1960s. The tidal power station has not been able to be developed and utilized on a large scale due to its high cost. Other forms of hydropower, such as wave power, are still in experimental research. (See hydropower station)

In order to achieve different types of hydropower development, knowledge of hydrology, geology, hydraulic structures, hydraulic machinery, electrical installations, water conservancy surveys, water conservancy planning, water conservancy engineering construction, water conservancy management, water conservancy economics, and grid operation needs to be used. The following aspects are studied.

Hydropower planning

Hydropower is an integral part of a comprehensive water resources development, management, and utilization system. Therefore, in the planning of hydropower projects, we must comprehensively consider the needs of power generation, flood prevention, irrigation, navigation, driftwood, water supply, aquaculture, tourism and other aspects from the full use of water resources and the comprehensive planning of rivers. Fully meet the requirements of all relevant parties and achieve the greatest national economic benefits. Hydropower resources are also one of the power sources. When planning for power, you must also plan based on energy conditions. In areas with abundant water resources, priority should be given to the development of hydropower and the full use of renewable energy in order to save precious coal, petroleum and other resources. Hydropower and thermal power are the two main power generation methods today. In a power system that has both methods, they should exert their own characteristics in order to obtain the best economic benefits of the system. In general, thermal power generation should bear the stable part of the power system load (or called the base load part), so that it runs as efficiently as possible, which can save system fuel consumption, which is conducive to safe and economical operation. Hydropower generation is more flexible because of startup and shutdown. For the load change part of the power system, including

Hydropower

Including peak load and accident standby. Hydroelectric power generation is also suitable for the tasks of frequency regulation and equalization for power systems.

Hydroelectric building

Hydropower station buildings include: water retaining structures required to form reservoirs, such as dams, sluices, etc .; drainage structures that discharge excess water, such as spillways, overflow dams, and drainage holes; water inlets for water generation; Water diversion buildings from water inlets to turbines; flat-water buildings (see surge tanks, front ponds), and hydropower plant buildings, tailraces, and booster switching stations of hydropower stations, which are designed to stabilize the flow and pressure changes of diversion buildings. The performance, applicable conditions, structural and structural forms, design, calculations, and construction techniques of these buildings must be carefully studied.

Hydropower equipment

Water turbines and hydro-generators are the basic equipment. In order to ensure safe and economic operation, corresponding machinery and electrical equipment are also arranged in the factory building, such as water turbine governor, oil pressure device, excitation equipment, low-voltage switch, automatic operation and protection system, etc. Booster transformer stations, high-voltage power distribution switchgear, transformers, lightning arresters, etc. are mainly set up in the booster switch stations of hydropower stations to receive and distribute electrical energy. The electric energy is finally delivered to users through transmission lines and step-down substations. These devices require safety, reliability, economical applicability, and high efficiency. For this reason, the design, construction and installation must be carefully studied.

In addition to its own conditions such as watercourse parameters and reservoir characteristics, hydropower station operations are closely related to grid dispatching. Hydropower station reservoirs should be kept at a high water level as far as possible to reduce waste water so as to maximize the power generation capacity of the hydropower station or minimize the fuel consumption of the power system. The goal is to obtain the highest economic benefits from the power grid. For hydropower stations and reservoirs with flood control or other water-use tasks, flood control scheduling and timely water supply should also be carried out, flood control and profitable storage capacity should be reasonably arranged, and basic requirements of relevant departments should be comprehensively established to establish an optimal operation mode of the reservoir. When there is a group of reservoirs in the power grid, the mutual compensation benefits of the reservoir groups must be fully considered. (See Hydropower Station Operation Dispatching)

Benefit evaluation of hydropower

The financial income from hydropower's power supply to the grid and users is its direct economic benefits, but there are also indirect benefits and social benefits from non-financial income. Some countries in Europe and the United States implement a variety of electricity price systems, such as calculating electricity prices for different times of the day and seasons of the year, different electricity prices for emergency power supply in the event of an accident, and electricity prices based on kilowatt capacity. For a long time, China has implemented a single electricity price based on electricity, but in addition to generating electricity, hydropower can also assume peak regulation, frequency regulation, phase regulation, and accident (rotation) backup of the power grid, bringing economic benefits to the entire power grid operation. Provide water for power generation and give play to comprehensive utilization benefits. Therefore, when carrying out the construction of hydroelectric power, we must consider the overall situation of the national economy, clarify the economic benefits, and carry out the national economic evaluation.

Hydropower Features

Renewable energy. As the water flow continues according to a certain hydrological cycle

Hydropower

Circulation is never interrupted, so hydropower is a renewable energy source. Therefore, the energy supply of hydropower is only the difference between the high water year and the low water year, without the problem of energy exhaustion. However, when encountering special dry years, the normal power supply of hydropower stations may be damaged due to insufficient energy supply, and the output will be greatly reduced.

Hydropower

Low cost of power generation. Hydroelectric power only uses the energy carried by the water flow, without the need to consume other power resources. In addition, the water flow used by the previous power station can still be used by the next power station. In addition, because the equipment of a hydropower station is relatively simple, its maintenance and maintenance costs are also much lower than thermal power plants of the same capacity. Taking into account fuel consumption, the annual operating cost of a thermal power plant is about 10 to 15 times that of a hydropower station of the same capacity. Therefore, the cost of hydropower is low, and it can provide cheap electricity.

Efficient and flexible. The hydro-generators of the main power equipment of hydroelectric power generation are not only more efficient, but also more flexible to start and operate. It can be quickly started and put into operation in a few minutes from a stationary state; it can complete the task of increasing and decreasing the load in a few seconds, and it can adapt to the needs of changing the power load without causing energy loss. Therefore, using hydropower to undertake tasks such as peak regulation, frequency regulation, load backup, and accident backup of the power system can improve the economic efficiency of the entire system.

Comprehensiveness of project benefits. Because damming and blocking water forms a vast artificial lake and controls the flow of water, the construction of hydropower stations generally has multiple benefits such as flood control, irrigation, shipping, water supply, and tourism. On the other hand, after the construction of the hydropower station, sedimentation may also occur, flooding cultural facilities such as good fields, forests and monuments, and disease transmission may occur near the reservoir area. The construction of a dam may also affect the life and reproduction of fish. The greatly increased position will adversely affect the growth of fruit trees and crops at its edges. The construction of large hydropower stations may also affect the climate of the river basin, leading to drought or flooding. Especially large reservoirs have the potential to induce earthquakes. Therefore, in the construction of large-scale hydropower stations in seismically active areas, the seismic resistance of the dam body, abutment and rocks on both sides of the bank must be studied and simulated, and fully demonstrated. These are the issues to be studied in hydropower development.

Large one-time investment. The earth and stone and concrete projects for the construction of the hydropower station are huge; it will cause considerable inundation losses, and huge resettlement costs must be paid; the construction period is longer than that of the thermal power plant construction, which affects the turnover of construction funds. Even if the beneficiary departments share some of the investment in water conservancy projects, the unit kilowatt investment of hydropower is much higher than that of thermal power. However, in future operations, the savings in annual operating expenses will be offset annually. The maximum allowable compensation period is related to the country's development level and energy policy. If the compensation period is less than the allowable value, it is considered reasonable to increase the installed capacity of the hydropower station.