River energy pros and cons. What are the advantages and disadvantages of hydraulic power plants compared to thermal? Environmental "pros" and "cons" of hydropower

Power plants are an essential part of every person's life as they convert energy into electricity. One station is a whole complex of activities, artificial and natural subsystems that serve to convert and distribute all types of energy sources. The whole process can be divided into several stages:

1. The process of extraction and processing of primary energy source.
2. Delivery to the power plant.
3. The process of converting primary energy into secondary energy.
4. Distribution of secondary (electrical or between consumers.

The electric power industry includes the production of energy at the station and its subsequent delivery through power lines. Such critical elements of this chain as power plants differ in the type of primary sources that are available in a given region.

Let us consider some types of transformation processes in more detail, as well as the advantages and disadvantages of each of them.

They belong to the group of traditional energy and occupy a significant share of the world's electricity generation (approximately 40%). The advantages and disadvantages of TPPs are shown in the following table:

Use as a primary source of energy for example, reservoirs and rivers. The advantages and disadvantages of HPPs are also summarized in the table.

Nuclear power plants (NPP) - a set of installations and activities intended for which is released as a result of the fission of atomic nuclei, into thermal, and then into the most important element of this system is also a complex of related devices. The table below shows the advantages and disadvantages of nuclear power plants.

An equally important stage is the transportation of fuel resources to the power plant. This process can be carried out in several ways, each with its own advantages and disadvantages. Consider the main modes of transportation:

• Water transport. Delivery is carried out with the help of tankers and bunkers.
• Automobile transport. Transportation is carried out in tanks. The ability to transport only liquid or gaseous fuel determines the existing advantages and disadvantages of road transport.
• Railway transport. Delivery in tanks and open wagons over long distances.
• Suspended and rarely used and only for very short distances.

Traditionally, hydroelectric power plants (HPPs) are a source of cheap electrical energy. In them, the energy potential of huge masses of water is converted into electricity.

What are hydroelectric power plants and how do they work

Most often for them on the rivers are built dams, thanks to which huge reservoirs of a water resource are formed. At the same time, the river on which the power plant is supposed to be built must be full-flowing in order to surely provide water to the turbines of electric generators all year round. In addition, it should have the largest possible slope. The ideal option for the construction of hydroelectric power stations are the canyons formed by the riverbeds.

The dam created to accommodate the station and other hydraulic structures provide the necessary pressure of the water flow that rotates the blades of hydraulic turbines and the rotors of electric generators. In addition to using the pressure of water for the production of electricity, the natural current of the water flow, called derivation, can be used. Sometimes both versions of water energy are used simultaneously.

The power generation equipment required by the power plant is installed directly in the hydroelectric power plant. There, units are installed in separate halls that directly convert the force of the water flow into the mechanical energy of the turbines, and then into electricity.

In addition, the hydroelectric power station must be equipped with various other equipment, with the help of which the control of the station's operation and its management are organized. The normal operation of the station is impossible without devices that distribute and transform electricity, and many other systems.

What are they like

According to the generated power, HPPs are usually divided into categories. This is due to the flow of water and the force of its pressure, as well as the efficiency of the generators and water turbines installed at the station. Plants producing 25 MW or more are considered powerful. Medium-power ones include those that produce less than 25 MW. The performance of low-power stations does not exceed 5 MW.

HPPs are high-pressure, when water comes from a height of more than 60 m, medium-pressure from 25 m high and low-pressure, where the water height can be from three to 25 meters. Their turbines are located in reinforced concrete or steel chambers. They may have different designs and technical parameters related to the indicators of the working water pressure.

At high-pressure stations, radial-axial and bucket turbines are operated. They are installed in special spiral chambers made of metal. Radial-axial and rotary-blade turbines are used mainly at stations where the average head pressure. Low-pressure hydroelectric power plants are mainly equipped with rotating blade turbines.

Depending on the scheme for using water resources, HPPs are divided into:

1. Channel.
2. Dam.
3. Derivative.
4. Hydroaccumulating.

In the first variant, the river is completely blocked by a dam. The water level in it rises to the design height. From it, water is discharged directly to the hydraulic turbines. Such a station is convenient where the riverbed narrows, and on rivers flowing through mountains.

There is also a dam in the dam scheme, but the production building of the HPP is located in its lower part. Here the water pressure is stronger than in the channel version. This requires the construction of special pressure tunnels for its supply to the turbines.

In diversion-type plants, water flows directly through the power plant building, where turbines are installed.

Pumped-storage HPPs allow accumulating hydropower for use during periods of peak loads. In non-stressful mode, for example, at night, its water turbines function as pumps, pumping water into the upper reservoir. When peak loads appear, water from it is directed to a pipeline that supplies it to the turbine blades.

Advantages of hydroelectric power plants

The construction and operation of hydroelectric power plants is accompanied by discussions about their pros and cons.

The positive factor of such electricity production is renewal of used natural resources. As a result, the cost of electrical energy obtained in this way is significantly lower than at other types of power plants. For example, at Russian hydroelectric power stations it is half that of thermal ones.

Hydrostations are flexible in management. With the help of their turbines, you can adjust the power of the station from minimum to maximum. At the same time, unlike thermal and some other stations, they are able to quickly gain operating power from minimal performance.

The operation of the HPP is not accompanied by harmful air pollution. Positive factors include the influence of their reservoirs on the formation of more moderate climatic indicators in the corresponding region.

The construction of dams and education improve navigation, influence the increase in fish stocks in them, and promote fish farming.

Their cons

Critics of HES rightly point to problems, primarily environmental, which are caused by their appearance. First of all, this is the flooding of large areas of agricultural land, including fertile lands. The remaining floodplain soil loses moisture. Many types of vegetation are disappearing. As a result, less valuable nutrients enter the seas and oceans.

Limited or stopped water flows at dams force unique ecological systems in riverbeds and floodplains to change. As a result, the rivers become shallow and polluted, the number of fish is reduced, and some of their species disappear. Dams sometimes prevent the spawning of migratory fish, forcing local fisheries to adapt to new conditions. Some invertebrates and other aquatic animals disappear with the simultaneous appearance of an abundance of midges. Many migratory birds are losing their usual nesting sites.

In the design of stations and their construction, priority is given only to areas with large water reserves. They are often much further from consumers than thermal power plants. However, other factors are not always taken into account. Hydroelectric power stations on mountain rivers, which are sometimes built in areas with high seismic hazard, represent a potential hazard.

Significantly higher capital costs are indicated in comparison with the construction of thermal power plants. During the construction of dams, huge expenditures are needed for the construction of locks to transfer ships to the desired water level.

One of the main advantages of small hydropower facilities is environmental safety. During their construction and subsequent operation, there are no harmful effects on the properties and quality of water. Reservoirs can be used both for fishery activities and as sources of water supply for the population. However, in addition to this, micro and small hydropower plants have many advantages. Modern stations are simple in design and fully automated, i.e. do not require the presence of a person during operation. The electric current generated by them meets the requirements of GOST in terms of frequency and voltage, and the stations can operate both in stand-alone mode, i.e. outside the power grid of the power system of the region or region, and as part of this power grid. And the full service life of the station is at least 40 years (at least 5 years before overhaul). Well, and most importantly, small-scale energy facilities do not require the organization of large reservoirs with the corresponding flooding of the territory and colossal material damage.

During the construction and operation of SHPPs, the natural landscape is preserved, there is practically no load on the ecosystem. The advantages of small hydropower - compared to fossil fuel power plants - can also include: low cost of electricity and operating costs, relatively inexpensive replacement of equipment, longer service life of HPPs (40-50 years), integrated use of water resources (electricity, water supply, land reclamation, water protection, fisheries).

Many of the small HPPs do not always provide guaranteed energy generation, being seasonal power plants. In winter, their energy output drops sharply, snow cover and ice phenomena (ice and sludge), as well as summer low water and drying up of rivers, can generally suspend their work. The seasonal nature of small HPPs requires redundant energy sources; a large number of them can lead to a loss of energy supply reliability. Therefore, in many areas, the capacity of small HPPs is considered not as the main one, but as a backup.

The reservoirs of small hydropower plants, especially mountainous and foothill areas, are very acutely affected by the problem of their silting and the related problem of rising water levels, flooding and flooding, reducing the hydropower potential of rivers and generating electricity. It is known, for example, that the reservoir of the Zemonechalskaya HPP on the Kura River was silted up by 60% within 5 years.

For fisheries, the dams of small hydroelectric power plants are less dangerous than medium and large ones, which block the migration routes of migratory and semi-anadromous fish and block spawning grounds. Although, in general, the creation of hydropower facilities does not completely eliminate the damage to the fish stock on the main rivers, since the river basin is a single ecological system and violations of its individual links inevitably affect the system as a whole.

I am sure that if an average person is asked a question about the differences between hydraulic and thermal power plants, he will answer: one works on hydraulics, the other on fuel. But I think the answer is more complicated...

Types of power plants

Today, there are three main types of power plants: hydraulic, thermal and nuclear.

The efficiency of nuclear power plants is the highest in relation to the cost of electricity generation. With proper and reasonable use, nuclear energy will hold a leading position in the near future.

There are still wind or solar power plants, but their productivity today is negligible and is able to provide a person with electricity only at the household level.

Advantages of hydraulic power plants

Among the advantages of hydraulic over thermal power plants, the following can be distinguished:

• lower cost of electricity;
• less harm to the environment;
• renewable source of energy conversion.

The production of electricity using the flow of water requires less finance than the production of electricity by burning fuel: there is no need to conduct costly mining and build logistics for their transportation.

A hydraulic power plant causes less damage to the environment during operation. There are no emissions into the atmosphere and hydrosphere of by-products and harmful substances from the production of electricity - gases, solid toxic waste, and the like.

Due to the natural water cycle, the source of electricity production (water) can be used repeatedly, in contrast to the one-time combustion of fuel.

Disadvantages of hydraulic power plants

Hydraulic power plants also have disadvantages:

• low efficiency compared to fuel;
• the cost of building a significant length of transmission lines;
• are located in a certain place on the banks of large rivers, at a distance from industrial centers, which complicates the repair work of the units and the delivery of bulky equipment to them.

These are the features of the production of these two types of power plants.

A hydroelectric power station is a power station that uses the energy of discharged water as a source of energy. They are most often erected on existing reservoirs, constructing artificial dams and reservoirs to store the required volume of water.

For effective generation of electricity at this kind of station, two main requirements must be met: year-round uninterrupted water supply and the presence of sharp river slopes.

Technology for generating electricity hydroelectric power plants is a transformation of the mechanical energy of water, due to the presence of different levels of heights through the use of engines and generators.

Today, there are the following types of hydroelectric power plants, which differ from each other in the way water is supplied - dam, diversion and pumped storage stations.

Dam hydroelectric power stations are the most popular and powerful type of stations. A reservoir is created by erecting artificial partitions to hold the flow of the river. The descent of water occurs for two reasons - when there is a need for electricity and to form the required level in the reservoir.

The diversion type is different in that it does not use the entire course of the river, but with the help of pipes and a drainage system, the required volume of water is taken, which is then sent to the turbine.

Hydrostorage stations are installations that store electrical energy and return it to the system if necessary, used to equalize the daily heterogeneity of the electrical load schedule.

Marine stations are also used, which operate through the energy of tides and waves.

Advantages of a hydroelectric power plant

Flexibility. Hydropower is recognized as a flexible source of electricity because a hydroelectric power plant can easily and quickly adapt to changing energy needs, increasing or slowing down the output of electricity. The existing turbine is up and running in just a few minutes.

Low electricity costs. The main advantage of a hydroelectric power plant is the absence of fuel costs and complete independence from fossil fuels. All such stations have a huge lifespan, even today there are hydroelectric power stations that were built about 100 years ago, and besides, they do not require many employees to maintain them.

Use for industrial purposes. A hydroelectric power plant is used both to serve the population and to provide electricity to certain plants.

Minimal carbon footprint. Hydroelectric power plants themselves are not capable of producing carbon dioxide, which can most often be formed only during the construction work of the station. The German scientist Paul Scherrer, after conducting research, came to the conclusion that hydropower ranks first in terms of the minimum production of carbon dioxide, followed by wind, nuclear energy and solar energy.

The benefits of creating a reservoir. Built reservoirs are often a great option for water sports, and some are even considered tourist attractions. Also, the water from them is perfect for irrigation or for breeding various types of fish in it. Plus, artificial dams help prevent floods.

Disadvantages of hydroelectric power plants

Environmental damage and loss of land. The huge reservoirs that are required for the operation of hydroelectric power plants are the causes of flooding of colossal areas of land located upstream of the dam, which means that forests, fields, swamps and their inhabitants are being destroyed.

Silting. The flow of water brings with it various particles and residues that harm both the dam and the power plant. Such deposits can reduce the size of the reservoir and impair the ability to prevent flooding. And also reduce electricity production.

Methane emissions. Hydroelectric power plants located in tropical regions, due to the huge amount of decaying plant materials, produce large volumes of methane. Therefore, before building a hydroelectric power station and a dam, it is necessary to clear the territory from forests in the area where an artificial reservoir is formed.

Resettlement. Many researchers consider the need to relocate the population living in the area of ​​the future reservoir to the significant disadvantages of the construction of hydroelectric power plants. At the beginning of the 21st century, the World Commission on Dams published its statistics, the data of which showed that due to the construction of dams, almost 80 million people around the world had to leave their places of residence.