The variety of options and uniqueness of technical solutions used in the construction of hydroelectric power plants is amazing. In fact, it is not so easy to find two identical stations. But there is still a classification of them, based on certain characteristics - criteria.
Method of creating pressure
Perhaps the most obvious criterion is method of creating pressure:
- run-of-river hydroelectric power station (HPP);
- diversion hydroelectric power station;
- pumped storage power plant (PSPP);
- tidal power station (TPP).
There are characteristic differences between these four main types of hydroelectric power plants. River hydroelectric power station is located on a river, blocking its flow with a dam to create pressure and a reservoir. Derivation hydroelectric power station usually located on winding mountain rivers, where it is possible to connect the branches of the river with a conduit to allow part of the flow to flow along a shorter path. In this case, the pressure is created by the natural difference in the terrain, and the reservoir may be completely absent. Pumped storage power plant consists of two pools located at different levels. The pools are connected by conduits through which water can flow into the lower pool from the upper and be pumped back. tidal power station located in a bay blocked by a dam to create a reservoir. Unlike pumped storage power plant The operating cycle of the TES depends on the tidal phenomenon.
Pressure value
Based on the amount of pressure created by the hydraulic structure (HTS), hydroelectric power stations are divided into 4 groups:
- low-pressure - up to 20 m;
- medium-pressure - from 20 to 70 m;
- high-pressure - from 70 to 200 m;
- ultra-high-pressure - from 200 m.
It is worth noting that the classification according to pressure value is relative in nature and varies from one source to another.
Installed power
According to the installed capacity of the station - the sum of the rated capacities of the generating equipment installed on it. This classification has 3 groups:
- micro-hydroelectric power station - from 5 kW to 1 MW;
- small hydroelectric power plants - from 1 kW to 10 MW;
- large hydroelectric power plants - over 10 MW.
Classification by installed capacity as well as in terms of pressure, it is not strict. The same station may be classified in different groups in different sources.
Dam design
There are 4 main groups of hydroelectric dams:
- gravitational;
- buttress;
- arched;
- arched-gravity.
Gravity Dam It is a massive structure that holds water in a reservoir due to its weight. Buttress dam uses a slightly different mechanism - it compensates for its relatively low weight with the weight of water pressing on the inclined face of the dam from the upstream side. Arch dam , perhaps the most elegant, has the shape of an arch, the base resting on the banks and the rounded part convex towards the reservoir. Water is retained at the arch dam due to the redistribution of pressure from the front of the dam to the banks of the river.
Machine room location
More precisely, according to location of the turbine room relative to the dam, not to be confused with layout! This classification is only relevant for run-of-river, diversion and tidal power plants.
- channel type;
- dam type.
At channel type the turbine room is located directly in the body of the dam, dam type - is erected separately from the dam body and is usually located immediately behind it.
Layout
The word “layout” in this context means the location of the turbine room relative to the river bed. Be careful when reading other literature on this topic, because the word layout has a broader meaning. The classification is valid only for run-of-the-river and diversion power plants.
- channel;
- floodplain;
- coastal.
At channel layout the turbine hall building is located in the riverbed, floodplain layout - in the floodplain of the river, and when coastal layout - on the river bank.
Overregulation
Namely, the degree of regulation of the river flow. The classification is only relevant for run-of-the-river and diversion hydroelectric power plants.
- daily regulation (operation cycle - one day);
- weekly regulation (work cycle - one week);
- annual regulation (operation cycle - one year);
- long-term regulation (operation cycle - several years).
The classification reflects how large the hydroelectric reservoir's reservoir is in relation to the volume of the river's annual flow.
All the above criteria are not mutually exclusive, that is, the same hydroelectric power station can be of a river type, high-pressure, medium power, run-of-river layout with a dam-type machine room, an arch dam and an annual regulation reservoir.
List of sources used
- Bryzgalov, V.I. Hydroelectric power plants: textbook. allowance / V.I. Bryzgalov, L.A. Gordon - Krasnoyarsk: IPC KSTU, 2002. - 541 p.
- Hydraulic structures: in 2 volumes / M.M. Grishin [and others]. - Moscow: Higher School, 1979. - T.2 - 336 p.
Hydroelectric power plants or hydroelectric power plants use the potential energy of river water and are today a common means of producing electricity from renewable sources.
Hydroelectric power supplies more than 16% of the world's electricity (99% in Norway, 58% in Canada, 55% in Switzerland, 45% in Sweden, 7% in the USA, 6% in Australia) of more than 1060 GW of installed capacity. Half of this capacity is located in five countries: China (212 GW), Brazil (82.2 GW), USA (79 GW), Canada (76.4 GW) and Russia (46 GW). Apart from these four countries with relative abundance (Norway, Canada, Switzerland and Sweden), hydropower is usually applied at peak load because hydroelectric power can be easily stopped and started. This also means that it is an ideal addition to the on-grid system and is used most effectively in Denmark.
Hydroelectric power plants use the energy of falling water to generate electricity. The turbine converts the kinetic force of the falling H2O into mechanical force. The generator then converts the mechanical energy from the turbine into electrical energy.
Hydropower in the world
Hydropower uses large areas and is not a major option for the future in developed countries because most of the large sites in these countries with potential for hydropower development are either already in operation or are inaccessible for other reasons, such as environmental concerns. Mainly in China and Latin America, hydropower growth is expected until 2030. China has commissioned $26 billion worth of hydroelectric power plants in recent years, producing 22.5 GW. Hydropower in China has played a role in displacing over 1.2 million people from dam sites.
The main advantage of hydraulic systems is their ability to handle seasonal (as well as daily) high peak loads. In practice, the use of stored water energy is sometimes complicated by irrigation requirements that may occur out of phase with peak loads.
Running hydraulic systems from a river is usually much cheaper than creating dams and has potentially wider applications. Small hydroelectric power plants under 10 MW represent about 10% of the world's potential and most of them operate from rivers.
There are three types of hydropower structures: hydroelectric power plants, pumping stations, and pumped storage power plants.
Operating principle of hydroelectric power station
The operating principle of a hydroelectric power station is when water energy is converted into mechanical energy through hydraulic turbines. The generator converts this mechanical energy from the water into electricity.
The operation of the generator is based on Faraday principles: when a magnet moves past a conductor, electricity is generated. In a generator, electromagnets are created by current direct current. They create pole fields and are installed around the perimeter of the rotor. The rotor is attached to a shaft that rotates the turbines at a fixed speed. When the rotor rotates, it causes a change of poles in the conductor mounted in the stator. This, in turn, according to Faraday's law, generates electricity at the terminals of the generator.
Composition of hydroelectric power station
Hydroelectric power plants range in size from “micro hydropower plants” that power a few homes to giant dams that provide electricity to millions of people.
Most conventional hydroelectric power plants include four main components:
The use of hydropower peaked in the mid-20th century, but the idea of using H2O to generate electricity goes back thousands of years. More than 2,000 years ago, the Greeks used a water wheel to grind wheat into flour. These ancient wheels are like turbines today, through which water flows.
Hydropower plants are the world's largest source of renewable energy.
What is a hydroelectric power plant?
Hydroelectric power plants are very efficient sources of energy. They use renewable resources - the mechanical energy of falling water. The water back-up necessary for this is created by dams that are erected on rivers and canals. Hydraulic installations make it possible to reduce transportation and save mineral fuel (approximately 0.4 tons of coal are consumed per 1 kWh). They are quite easy to operate and have a very high efficiency (more than 80%). The cost of this type of installation is 5-6 times lower than thermal power plants, and they require much less maintenance personnel.
Hydraulic installations are represented by hydroelectric power plants (HPP), pumped storage power plants (PSP) and tidal power plants (TPP). Their placement largely depends on natural conditions, for example, the nature and regime of the river. In mountainous areas, high-pressure hydroelectric power plants are usually built; on lowland rivers, installations with lower pressure but higher water flow are used. Hydraulic construction in plains is more difficult due to the predominance of soft foundations under dams and the need to have large reservoirs to regulate flow. The construction of hydroelectric power stations on the plains causes flooding of adjacent areas, which causes significant material damage.
A hydroelectric power station consists of a sequential chain of hydraulic structures that provide the necessary concentration of water flow and the creation of pressure, and energy equipment that converts the energy of water moving under pressure into mechanical rotational energy, which, in turn, is converted into electrical energy.
The pressure of a hydroelectric power station is created by the concentration of the fall of the river on the site being used by a dam, or diversion, or a dam and diversion together. The main power equipment of a hydroelectric power station is located in the hydroelectric power station building: in the turbine room of the power plant - hydraulic units, auxiliary equipment, automatic control and monitoring devices; in the central control post there is a control panel for the operator-dispatcher or an automatic operator of the hydroelectric power station. The step-up transformer substation is located both inside the hydroelectric power station building and in separate buildings or in open areas. Switchgears are often located in open areas. A hydroelectric power plant building can be divided into sections with one or more units and auxiliary equipment, separated from adjacent parts of the building. An installation site is created at or inside the hydroelectric power station building for the assembly and repair of various equipment and for auxiliary operations for the maintenance of the hydroelectric power station.
Based on installed capacity (in MW), hydroelectric power stations are distinguished between powerful (over 250), medium (up to 25) and small (up to 5). The power of a hydroelectric power station depends on the pressure Nb (the difference between the levels of the upper and lower pools), the water flow Q (m3/sec) used in hydraulic turbines, and the efficiency of the hydraulic unit hg. For a number of reasons (due to, for example, seasonal changes in the water level in reservoirs, fluctuations in the load of the power system, repairs of hydraulic units or hydraulic structures, etc.), the pressure and flow of water continuously change, and in addition, the flow changes when regulating the power of a hydroelectric power station. There are annual, weekly and daily cycles of hydroelectric power station operation.
According to the maximum used pressure, hydroelectric power stations are divided into high-pressure (more than 60 m), medium-pressure (from 25 to 60 m) and low-pressure (from 3 to 25 m) hydroelectric power stations. On lowland rivers, pressures rarely exceed 100 m; in mountainous conditions, pressures of up to 300 m or more can be created using a dam, and with the help of diversion - up to 1500 m. The classification by pressure approximately corresponds to the types of power equipment used: at high-pressure hydroelectric power stations, bucket and radial hydroelectric power plants are used. axial turbines with metal spiral chambers; on medium-pressure ones - rotary-blade and radial-axial turbines with reinforced concrete and metal spiral chambers, on low-pressure ones - rotary-blade turbines in reinforced concrete spiral chambers, sometimes horizontal turbines in capsules or in open chambers. The division of hydroelectric power stations according to the pressure used is of an approximate, conditional nature.
According to the scheme of water resource use and pressure concentration, hydroelectric power stations are usually divided into run-of-river, dam-based, diversion with pressure and free-flow diversion, mixed, pumped storage and tidal. In run-of-river and dam-based hydroelectric power plants, the water pressure is created by a dam that blocks the river and raises the water level in the upper pool. At the same time, some flooding of the river valley is inevitable. If two dams are built on the same section of the river, the flood area is reduced. On lowland rivers, the largest economically permissible flood area limits the height of the dam. Run-of-river and near-dam hydroelectric power stations are built both on lowland high-water rivers and on mountain rivers, in narrow compressed valleys.
In addition to the dam, the structures of a run-of-the-river hydroelectric power station include the hydroelectric power station building and spillway structures. The composition of hydraulic structures depends on the head height and installed power. At a run-of-the-river hydroelectric power station, the building with the hydraulic units housed in it serves as a continuation of the dam and together with it creates a pressure front. At the same time, the upper pool is adjacent to the hydroelectric power station building on one side, and the lower pool is adjacent to it on the other. The supply spiral chambers of hydraulic turbines with their inlet sections are laid under the level of the upstream, while the outlet sections of the suction pipes are immersed under the level of the downstream.
In accordance with the purpose of the waterworks, it may include shipping locks or a ship lift, fish passage structures, water intake structures for irrigation and water supply. In run-of-the-river hydroelectric power plants, sometimes the only structure that allows water to pass through is the power plant building. In these cases, useful water sequentially passes through the inlet section with waste-retaining gratings, a spiral chamber, a hydraulic turbine, and a suction pipe, and the river's flood flows are discharged through special conduits between adjacent turbine chambers. Run-of-river hydroelectric power plants are characterized by pressures of up to 30-40 m; The simplest run-of-the-river hydroelectric power stations also include previously built rural (hydroelectric power stations) hydroelectric power stations of small capacity. On large lowland rivers, the main channel is blocked by an earthen dam, adjacent to which is a concrete spillway dam and a hydroelectric power station building is constructed. This arrangement is typical for many domestic hydroelectric power plants on large lowland rivers. Volzhskaya HPP named after. 22nd Congress of the CPSU - the largest among the river-bed stations.
The most powerful hydroelectric power stations were built on the Volga, Kama, Angara, Yenisei, Ob and Irtysh. A cascade of hydroelectric power stations is a group of hydroelectric power stations located in steps along the flow of water flow with the aim of fully sequentially using its energy. Installations in a cascade are usually connected by a common regime in which the reservoirs of the upper stages have a regulatory influence on the reservoirs of the lower stages. Industrial complexes specializing in energy-intensive industries are being formed on the basis of hydroelectric power stations in the eastern regions.
The most efficient resources in terms of technical and economic indicators are concentrated in Siberia. One example of this is the Angara-Yenisei cascade, which includes the largest hydroelectric power stations in the country: Sayano-Shushenskaya (6.4 million kW), Krasnoyarsk (6 million kW), Bratsk (4.6 million kW), Ust-Ilimskaya (4.3 million kW). The Boguchanovskaya hydroelectric power station (4 million kW) is under construction. The total capacity of the cascade is currently more than 20 million kW.
When constructing hydroelectric power stations, the goal is usually to generate electricity, improve conditions for navigation on the river and irrigate land. Hydroelectric power plants usually have reservoirs that allow them to store water and regulate its flow and, therefore, the operating power of the station so as to provide the most beneficial mode for the energy system as a whole.
The regulatory process is as follows. During a period of time when the load on the power system is low (or the natural inflow of water in the river is large), the hydroelectric power station consumes water in an amount less than the natural inflow. In this case, water accumulates in the reservoir, and the operating capacity of the station is relatively small. At other times, when the system load is high (or the water inflow is small), the hydroelectric power plant uses water in an amount that exceeds the natural inflow. In this case, the water accumulated in the reservoir is consumed, and the operating power of the station increases to maximum. Depending on the volume of the reservoir, the regulation period, or the time required to fill and operate the reservoir, can be a day, a week, several months or more. During this time, the hydroelectric power plant can use a strictly defined amount of water, determined by natural inflow.
When hydroelectric power plants operate together with thermal and nuclear power plants, the load of the power system is distributed between them so that, at a given water flow during the period under consideration, the demand for electrical energy is met with minimal fuel consumption (or minimal fuel costs) in the system. Experience in operating energy systems shows that during most of the year it is advisable to operate hydroelectric power plants in peak mode. This means that during the day the operating power of a hydroelectric power station must vary within wide limits - from minimum during hours when the load on the power system is low to maximum during hours of the highest load on the system. With this use of hydroelectric power plants, the load of thermal stations is leveled and their operation becomes more economical.
During periods of flood, when the natural influx of water in the river is high, it is advisable to use hydroelectric power stations around the clock with an operating capacity close to maximum, and thus reduce idle water discharge through the dam. The most profitable mode of a hydroelectric power plant depends on many factors and must be determined by appropriate calculations.
The operation of hydroelectric power plants is characterized by frequent starts and stops of units, a rapid change in operating power from zero to nominal. Hydraulic turbines by their nature are adapted to this regime. For hydrogenerators, this mode is also acceptable, since, unlike steam turbine generators, the axial length of the hydrogenerator is relatively small and temperature deformations of the winding rods are less pronounced. The process of starting the hydraulic unit and gaining power is fully automated and requires only a few minutes.
The duration of use of the installed capacity of hydroelectric power plants is usually shorter than that of thermal power plants. It is 1500-3000 hours for peak stations and up to 5000-6000 hours for base stations.
The unit cost of a hydroelectric station (RUB/MW) is higher than the unit cost of a thermal station of the same capacity due to the larger volume of construction work. The construction time of a hydroelectric power station is also longer than the construction time of a thermal station. However, the cost of electricity generated by hydroelectric power plants is significantly lower than the cost of energy from thermal power plants, since operating costs do not include the cost of fuel.
It is advisable to build hydroelectric power stations on mountain and sesquicentral rivers. On lowland rivers, their construction can lead to the flooding of large areas of floodplain meadows and arable land, forests, a decrease in fish stocks and other consequences.
Small hydraulic turbines are very specific in the principle of their operation, in contrast to the turbines of conventional hydroelectric power plants. The process of operation of a micro-hydraulic turbine is interesting in that the properties of its structure can provide for a specific object the volume of water masses that will flow to the parts of the hydraulic turbine (blades), bring the generator into working condition (the generator plays the role of generating electricity).
The process of increasing water pressure is ensured by the formation of “derivation” - water discharges in a free flow (provided that this micro hydroelectric power station is of a diversion type) or a dam (provided that it is a mini thermal power plant of the dam type).
Power of mini hydroelectric power station
The power level of a mini hydroelectric power station directly depends on the conditions in which its hydraulic properties are located:
- Water flow is the volume of water masses (l) that passes through the turbine in a certain period of time. It is customary to take 1-2 seconds for this period.
- Water pressure is the distance between two opposite points of the water mass (one is located at the top, the other at the bottom). The pressure has a number of characteristic features, on which the types of micro hydroelectric power stations depend (high pressure, medium pressure, low pressure)
The peculiarity of the operation of a micro hydroelectric power station is assessed from the point of view of its territorial location. For example, a pressure micro hydroelectric power station works by diverting water flows through a special channel made of wood, located at a certain angle of inclination, which allows water to flow faster. The water pressure in such a hydroelectric power station depends on how long the channel is. Next, the water flows into the pressure pipeline, after which it enters the hydraulic unit, which is located in the lower part. The recycled water is then forced back to its source by extrusion.
Location of mini hydroelectric power station
It is important to note that the position of the hydraulic turbine may be different depending on the type of construction:
- Horizontal position. This position of the hydraulic turbine leads to a natural increase in the size of the mini hydroelectric power station itself (with the help of a turbine shaft, which also increases the size of the energy system during rotation, as well as a change in the scale of the turbine room). However, it is worth noting that the construction of such hydraulic turbines is not more complicated than others, but on the contrary, simplifies it.
- Vertical arrangement. This type of arrangement helps to reduce the size of the hydroelectric power station, improves the balance of the axial lines and its compactness. This placement is more complex to construct, since it creates the need for a detailed balance of the axis in the rotational element. Also in such a situation, it is important to be more careful about the mandatory position of the working floor, when it is in one horizontal line, and its strength characteristics, so that they are able to withstand the weight of the entire structure. The vertical position increases the pressure on the axis of the structure.
Application of mini hydroelectric power station
In general, small hydroelectric power plants are used mainly for their application in remote areas of residential buildings. They cannot be serious competitors to large power plants, but rather serve to ensure energy savings. Recently, a number of people have been using both hydroelectric power plants, solar batteries and various wind control installations. The turbines described in this article may soon become one with these innovative energy sources, which will ultimately lead to the creation of new electrical circuits and models.
What can these structures be used for?
- to provide electricity to private property;
- for remote industrial areas;
- for electric charging stations;
- for temporary use.
Advantages of mini hydroelectric power stations
Small hydropower plants have a number of special advantages:
- they are available in two versions: fixed to the bottom of the reservoir, and also with special hooks that allow work to be carried out on the surface
- the installation can reach a power of 5 kW, in order to increase the power and efficiency of hydroelectric power plants, turbines are installed as modules
- Hydroelectric power stations do not negatively affect the environment during the construction process, because To create it, natural water is used, which is directed into a certain flow and sets the blades in motion.
Turbines for mini hydroelectric power stations
Now let's talk directly about hydraulic turbines for mini hydroelectric power stations and what we need for its construction. Characteristics and operating features of the hydraulic turbine:
- The temperature of the water supplied to the turbine must exceed +4 °C.
- The temperature that should be in the block module is +15 °C and above.
- The sound pressure, the source of which is located 1 m from the hydraulic turbine, is 80 dB and no more.
- The outer surface of the hydraulic turbine must be heated to a temperature no higher than +45°C, provided that the air temperature is around +25°C.
Let's consider the example of a well-balanced and operating hydraulic turbine under ideal conditions.
Let's assume that we have a flow-through hydraulic turbine, radial, pressure-driven with medium pressure, which provides a tangential supply of water to the blades, the shaft is horizontal. These types of pipes are classified as “quiet”. They have the peculiarity of adapting to the environment, installation location and various altitude pressure differences. If the water flow changes sharply, then the turbine uses a two-chamber bag design, which makes the device work better.
The body of any hydraulic turbine is made of structural steel; it is strong and reliable. The costs of materials and construction are significantly reduced compared to hydraulic turbines for conventional hydroelectric power plants. The most common material used for the construction of a hydraulic turbine will withstand differences from 90 to 120 meters, some parts are made of stainless steel (casing, pipelines).
In new generation hydraulic turbines, it is possible to replace the generator and impeller without severe deformation and alteration. It is worth noting that the impeller has the property of self-cleaning due to water flows that pass through the impeller area during operation. During the design of the generator and the hydraulic turbine itself, a number of measures are taken to reduce the cavitation level. Current hydraulic turbines are 100 percent free of this problem.
The main part of a hydraulic turbine is the impeller. The material for the manufacture of blades is often profile-type steel. Due to their properties, the blades can create an axial force, facilitating the work of the bearings, and the impellers themselves are in constant balance. The duration of operation of the impeller axis is determined by its position; for longer operation it is installed at the bearing level.
Features of hydraulic turbines for mini hydroelectric power stations
- Can be used in purification systems to obtain high-quality drinking water.
- It is possible to connect an industrial generator.
- Increased requirements for generator reliability.
Some characteristics of the technical plan:
- Height difference: 3 - 200 m
- Water flow: 0.03 - 13 cubic meters per second
- Power: 5 - 3,000 kW
- Number of blades located on the axial sector: 37
- Efficiency: 84% - 87%
Of course, mini hydroelectric power stations are unlikely to become the main source of energy, but their use is quite advisable as a means of reducing the load on the main power supply network, especially during periods of peak consumption.
A hydroelectric power station is a complex of complex hydraulic structures and equipment. Its purpose is to convert the energy of water flow into electrical energy. Hydropower is one of the so-called renewable energy sources, i.e. it is practically inexhaustible.
The most important hydraulic structure is a dam. It retains water in the reservoir and creates the necessary water pressure. A hydraulic turbine is the main engine in a hydroelectric power station. With its help, the energy of water moving under pressure is converted into mechanical rotational energy, which is then (thanks to an electric generator) converted into electrical energy. Hydraulic turbine, hydrogenerator, automatic monitoring and control devices - consoles are located in the turbine room of the hydroelectric power station. Step-up transformers can be located both inside the building and in open areas. Switchgears are most often installed outdoors near the power plant building.
In the Soviet Union, which has large hydropower resources (11112% of the world's total), extensive construction of hydroelectric power stations has begun. Based on installed hydroelectric capacity. Only in the 30 post-war years, from 1950, stations were divided into small - until 1980, electricity production increased by up to 5 MW, medium - from 5 to 25 and large - hydroelectric power stations increased more than 10 times. over 25 MW. There are 20 hydroelectric power stations in our country, each of which has an installed capacity exceeding 500 MW. The largest of them are the Krasnoyarsk (6000 MW) and Sayano-Shushenskaya (6400 MW) hydroelectric power stations.
The construction of hydroelectric power stations is unthinkable without a comprehensive solution to many problems. It is necessary to satisfy the needs not only of energy, but also of water transport, water supply, irrigation, and fisheries. These tasks are best met by the principle of cascading when not one, but a number of hydroelectric power stations are built on the river, located along the river. This makes it possible to create several reservoirs located successively on the river at different levels, which means more fully using the river flow, its energy resources and maneuvering the power of individual hydroelectric power stations. Cascades of hydroelectric power stations have been built on many rivers. In addition to the Volzhsky, cascades were built on the Kama, Dnieper, Chirchik, Hrazdan, Irtysh, Rioni, and Svir. The most powerful Angara-Yenisei cascade with the world's largest hydroelectric power stations - Bratsk, Krasnoyarsk, Sayano-Shushenskaya and Boguchanskaya with a total capacity of about 17 GW and an annual production of 76 billion kWh of electricity.
There are several types of power plants that use the energy of water flow. In addition to hydroelectric power plants, pumped storage power plants (PSPPs) and tidal power plants (TPPs) are also being built. At first glance, you will hardly notice the difference between a conventional hydroelectric power plant and a hydro-storage power plant. The same building where the main power equipment is located, the same power lines. There is no fundamental difference in the method of generating electricity. What are the features of pumped storage power plants?
Unlike a hydroelectric power station, a pumped storage station requires two reservoirs (not one) with a capacity of several tens of millions of cubic meters each. The level of one should be several tens of meters higher than the other. Both reservoirs are connected to each other by pipelines. A pumped storage power station building is being built on the lower reservoir. In it, the so-called reversible hydraulic units - hydraulic turbines and electric generators are placed on the same shaft. They can work both as current generators and as electric water pumps. When energy consumption decreases, for example at night, hydraulic turbines act as pumps, pumping water from the lower reservoir to the upper one. In this case, generators operate as electric motors, receiving electrical energy from thermal and nuclear power plants. When electricity consumption increases, pumped storage power plant hydraulic units switch to reverse rotation. Water falling from the upper reservoir to the lower one rotates hydraulic turbines and generators generate electrical energy. Thus, at night, a pumped storage power plant, as it were, accumulates electricity generated by other power plants, and releases it during the day. Therefore, pumped storage power plants usually serve, as power engineers say, to cover “peaks” of load, i.e., it provides energy when it is especially needed. There are more than 160 pumped storage power plants operating around the globe. In our country, the first pumped storage power plant was built near Kiev. It has a low head, only 73 m, and a total power of 225 MW.
A larger pumped storage power plant has come into operation in the Moscow region, with a capacity of 1.2 GW and a head of 100 m.
Typically pumped storage power plants are built on rivers. But, as it turned out, such power plants can be built on the shores of seas and oceans. Only there they received a different name - tidal power plants (TPP).
Twice a day at the same time, the ocean level rises and falls. It is the gravitational forces of the Moon and the Sun that attract masses of water. Far from the coast, fluctuations in water level do not exceed 1 m, but near the coast they can reach 13 m, as, for example, in Penzhinskaya Bay on the Sea of Okhotsk.
If a bay or the mouth of a river is blocked with a dam, then at the moment of the greatest rise in water, hundreds of millions of cubic meters of water can be locked in such an artificial reservoir. When the tide goes out in the sea, a difference is created between the water levels in the reservoir and in the sea, which is sufficient to rotate the hydraulic turbines installed in the PES buildings. If there is only one reservoir, the PES can generate electrical energy continuously for 4-5 hours with breaks of 1-2 hours, respectively, four times a day (the water level in the reservoir changes so many times during high and low tides).
To eliminate uneven power generation, the station's reservoir is divided by a dam into 2-3 smaller ones. One maintains the low tide level, the other maintains the high tide level, and the third serves as a reserve.
Hydraulic units are installed at the TPP, which are capable of operating with high efficiency both in generator (producing electricity) and pumping mode (pumping water from a reservoir with a low water level to a reservoir with a high level). In pump mode, the PES operates when excess electricity appears in the power system. In this case, the units pump up or pump out water from one reservoir to another.
In 1968, the first pilot industrial power plant in our country was built on the coast of the Barents Sea in Kislaya Bay. The power plant building houses 2 hydraulic units with a capacity of 400 kW.
Ten years of experience in operating the first TPP allowed us to begin drawing up projects for the Mezen TPP on the White Sea, Penzhinskaya and Tugurskaya on the Sea of Okhotsk.
Harnessing the great forces of the tides of the world's oceans, even the ocean waves themselves, is an interesting problem. They are just beginning to solve it. There is a lot to be studied, invented, designed.
The construction of large energy giants - be it hydroelectric power plants, pumped storage power plants or power plants - is every time an exam for builders. Here the work of workers of the highest qualifications and different specialties is combined - from concrete masters to climbers.
