List of the largest geothermal power plants in the world. What are geothermal power plants. Positive and negative aspects of GeoPP

Kirill Degtyarev, researcher, Moscow State University them. M. V. Lomonosova

(End. Beginning see “Science and Life” No.)

Collector for collecting thermal boron water in Larderello (Italy), first half of the 19th century.

Motor and inverter used at Larderello in 1904 in the first geothermal electricity generation experiment.

Schematic diagram of the operation of a thermal power plant.

Operating principle of GeoPP using dry steam. Geothermal steam coming from a production well is passed directly through a steam turbine. The simplest existing operating scheme for GeoPP.

The operating principle of GeoPP with an indirect scheme. Hot underground water from the production well is pumped into the evaporator, and the resulting steam is supplied to the turbine.

Operating principle of binary GeoPP. Hot thermal water interacts with another liquid that performs the functions of a working fluid and has a lower boiling point.

Scheme of operation of a petrothermal system. The system is based on the use of a temperature gradient between the surface of the earth and its interior, where the temperature is higher.

Schematic diagram of a refrigerator and heat pump: 1 - condenser; 2 - throttle (pressure regulator); 3 - evaporator; 4 - compressor.

Mutnovskaya GeoPP in Kamchatka. At the end of 2011, the installed capacity of the station was 50 MW, but it is planned to increase it to 80 MW. Photo by Tatyana Korobkova (Research Laboratory of Renewable Energy, Faculty of Geography, M.V. Lomonosov Moscow State University.)

The use of geothermal energy has a very long history. One of the first known examples is Italy, a place in the province of Tuscany, now called Larderello, where even in early XIX centuries, local hot thermal waters, flowing naturally or extracted from shallow wells, were used for energy purposes.

Water from underground springs, rich in boron, was used here to obtain boric acid. Initially, this acid was obtained by evaporation in iron boilers, and ordinary wood from nearby forests was taken as fuel, but in 1827 Francesco Larderel created a system that worked on the heat of the waters themselves. At the same time, the energy of natural water vapor began to be used to operate drilling rigs, and at the beginning of the 20th century - for heating local houses and greenhouses. There, in Larderello, in 1904, thermal water vapor became an energy source for generating electricity.

The example of Italy was followed by several other countries at the end of the 19th and beginning of the 20th centuries. For example, in 1892, thermal waters were first used for local heating in the USA (Boise, Idaho), in 1919 in Japan, and in 1928 in Iceland.

In the USA, the first power plant operating on hydrothermal energy appeared in California in the early 1930s, in New Zealand - in 1958, in Mexico - in 1959, in Russia (the world's first binary GeoPP) - in 1965 .

Old principle on a new source

Electricity generation requires a higher temperature of the hydrosource than for heating - more than 150 o C. The operating principle of a geothermal power plant (GeoPP) is similar to the operating principle of a conventional thermal power plant (CHP). In fact, a geothermal power plant is a type of thermal power plant.

At thermal power plants, the primary energy source is usually coal, gas or fuel oil, and the working fluid is water vapor. Fuel, when burned, heats water into steam, which rotates a steam turbine, which generates electricity.

The difference between a GeoPP is that the primary source of energy here is the heat of the earth’s interior and the working fluid in the form of steam is supplied to the turbine blades of the electric generator in a “ready” form directly from the production well.

There are three main operating schemes for GeoPPs: direct, using dry (geothermal) steam; indirect, based on hydrothermal water, and mixed, or binary.

The use of one or another scheme depends on the state of aggregation and temperature of the energy carrier.

The simplest and therefore the first of the mastered schemes is direct, in which steam coming from the well is passed directly through the turbine. The world's first geoelectric power station in Larderello in 1904 also operated on dry steam.

GeoPPs with an indirect operating scheme are the most common in our time. They use hot underground water, which is pumped under high pressure into an evaporator, where part of it is evaporated, and the resulting steam rotates a turbine. In some cases, additional devices and circuits are required to purify geothermal water and steam from aggressive compounds.

The exhaust steam enters the injection well or is used for heating the premises - in this case the principle is the same as when operating a thermal power plant.

At binary GeoPPs, hot thermal water interacts with another liquid that performs the functions of a working fluid with a lower boiling point. Both fluids are passed through a heat exchanger, where thermal water evaporates the working fluid, the vapors of which rotate the turbine.

This system is closed, which solves the problem of emissions into the atmosphere. In addition, working fluids with a relatively low boiling point make it possible to use not very hot thermal waters as a primary source of energy.

In all three schemes, a hydrothermal source is exploited, but petrothermal energy can also be used to generate electricity (see “Science and Life” No. 9, 2013).

The circuit diagram in this case is also quite simple. It is necessary to drill two interconnected wells - injection and production. Water is pumped into the injection well. At depth it is heated, then the heated water or steam formed as a result of strong heating is supplied to the surface through the production well. Then it all depends on how petrothermal energy is used - for heating or for generating electricity. A closed cycle is possible with pumping waste steam and water back into the injection well or another disposal method.

The disadvantage of such a system is obvious: to obtain a sufficiently high temperature of the working fluid, it is necessary to drill wells to great depths. And these are serious costs and the risk of significant heat loss when the fluid moves upward. Therefore, petrothermal systems are still less widespread compared to hydrothermal ones, although the potential of petrothermal energy is orders of magnitude higher.

Currently, the leader in the creation of so-called petrothermal circulation systems (PCS) is Australia. In addition, this area of geothermal energy is actively developing in the USA, Switzerland, Great Britain, and Japan.

Gift from Lord Kelvin

The invention of the heat pump in 1852 by physicist William Thompson (aka Lord Kelvin) provided humanity with a real opportunity to use the low-grade heat of the upper layers of the soil. The heat pump system, or as Thompson called it, the heat multiplier, is based on the physical process of transferring heat from environment to the refrigerant. Essentially, it uses the same principle as petrothermal systems. The difference is in the heat source, which may raise a terminological question: to what extent can a heat pump be considered a geothermal system? The fact is that in the upper layers, to depths of tens to hundreds of meters, the rocks and the fluids they contain are heated not by the deep heat of the earth, but by the sun. Thus, it is the sun in this case that is the primary source of heat, although it is taken, as in geothermal systems, from the ground.

The operation of a heat pump is based on the delay in heating and cooling of the soil compared to the atmosphere, resulting in the formation of a temperature gradient between the surface and deeper layers that retain heat even in winter, just as it happens in reservoirs. The main purpose of heat pumps is space heating. In essence, it is a “reverse refrigerator”. Both the heat pump and the refrigerator interact with three components: the internal environment (in the first case - a heated room, in the second - the cooled chamber of the refrigerator), the external environment - an energy source and a refrigerant (refrigerant), which is also a coolant that ensures heat transfer or cold.

A substance with a low boiling point acts as a refrigerant, which allows it to take heat from a source that has even a relatively low temperature.

In the refrigerator, liquid refrigerant flows through a throttle (pressure regulator) into the evaporator, where due to a sharp decrease in pressure, the liquid evaporates. Evaporation is an endothermic process requiring the absorption of heat from outside. As a result, heat is removed from the inner walls of the evaporator, which provides a cooling effect in the refrigerator chamber. Next, the refrigerant is drawn from the evaporator into the compressor, where it returns to a liquid state. This is a reverse process leading to the release of the removed heat into external environment. As a rule, it is thrown indoors, and the back wall of the refrigerator is relatively warm.

A heat pump works in almost the same way, with the difference that heat is taken from the external environment and enters through the evaporator internal environment- room heating system.

In a real heat pump, water is heated by passing through an external circuit placed in the ground or reservoir, and then enters the evaporator.

In the evaporator, heat is transferred to an internal circuit filled with a low-boiling point refrigerant, which, passing through the evaporator, changes from a liquid to a gaseous state, taking away heat.

Next, the gaseous refrigerant enters the compressor, where it is compressed to high pressure and temperature, and enters the condenser, where heat exchange occurs between the hot gas and the coolant from the heating system.

The compressor requires electricity to operate, however, the transformation ratio (ratio of consumed and generated energy) in modern systems high enough to ensure their effectiveness.

Currently, heat pumps are quite widely used for space heating, mainly in economic developed countries Oh.

Eco-correct energy

Geothermal energy is considered environmentally friendly, which is generally true. First of all, it uses a renewable and virtually inexhaustible resource. Geothermal energy does not require large areas, unlike large hydroelectric power stations or wind farms, and does not pollute the atmosphere, unlike hydrocarbon energy. On average, a GeoPP occupies 400 m 2 in terms of 1 GW of generated electricity. The same figure for a coal-fired thermal power plant, for example, is 3600 m2. The environmental advantages of GeoPPs also include low water consumption - 20 liters of fresh water per 1 kW, while thermal power plants and nuclear power plants require about 1000 liters. Note that these are the environmental indicators of the “average” GeoPP.

But there are still negative side effects. Among them, noise, thermal pollution of the atmosphere and chemical pollution of water and soil, as well as the formation of solid waste, are most often identified.

The main source of chemical pollution of the environment is thermal water itself (with high temperature and mineralization), often containing large quantities of toxic compounds, and therefore there is a problem of disposal of waste water and hazardous substances.

The negative effects of geothermal energy can be traced at several stages, starting with the drilling of wells. The same dangers arise here as when drilling any well: destruction of soil and vegetation cover, contamination of soil and groundwater.

At the stage of operation of the GeoPP, problems of environmental pollution remain. Thermal fluids - water and steam - usually contain carbon dioxide (CO 2), sulfur sulfide (H 2 S), ammonia (NH 3), methane (CH 4), table salt(NaCl), boron (B), arsenic (As), mercury (Hg). When released into the external environment, they become sources of pollution. In addition, an aggressive chemical environment can cause corrosive destruction of geothermal power plant structures.

At the same time, emissions of pollutants from GeoPPs are on average lower than from thermal power plants. For example, carbon dioxide emissions for every kilowatt-hour of electricity generated are up to 380 g at GeoPP, 1042 g at coal thermal power plants, 906 g - at fuel oil and 453 g - at gas thermal power plants.

The question arises: what to do with waste water? If the mineralization is low, it can be discharged into surface waters after cooling. Another way is to pump it back into the aquifer through an injection well, which is preferably and predominantly used at present.

Extraction of thermal water from aquifers (as well as pumping out ordinary water) can cause subsidence and soil movements, other deformations of geological layers, and micro-earthquakes. The probability of such phenomena is, as a rule, low, although isolated cases have been recorded (for example, at the GeoPP in Staufen im Breisgau in Germany).

It should be emphasized that most GeoPPs are located in relatively sparsely populated areas and in third world countries, where environmental requirements are less stringent than in developed countries. In addition, on this moment The number of GeoPPs and their capacities are relatively small. With larger-scale development of geothermal energy, environmental risks may increase and multiply.

How much is the Earth's energy?

Investment costs for the construction of geothermal systems vary in a very wide range - from 200 to 5000 dollars per 1 kW of installed capacity, that is, the cheapest options are comparable to the cost of constructing a thermal power plant. They depend, first of all, on the conditions of occurrence of thermal waters, their composition, and the design of the system. Drilling to great depths, creating a closed system with two wells, and the need to purify water can increase the cost many times over.

For example, investments in the creation of a petrothermal circulation system (PCS) are estimated at 1.6-4 thousand dollars per 1 kW of installed capacity, which exceeds construction costs nuclear power plant and comparable to the costs of building wind and solar power plants.

The obvious economic advantage of GeoTES is free energy. For comparison, in the cost structure of an operating thermal power plant or nuclear power plant, fuel accounts for 50-80% or even more, depending on current energy prices. Hence another advantage of the geothermal system: operating costs are more stable and predictable, since they do not depend on external energy price conditions. In general, the operating costs of geothermal power plants are estimated at 2-10 cents (60 kopecks - 3 rubles) per 1 kWh of power produced.

The second largest expense item after energy (and a very significant one) is, as a rule, the wages of plant personnel, which can vary dramatically across countries and regions.

On average, the cost of 1 kWh of geothermal energy is comparable to that for thermal power plants (in Russian conditions - about 1 ruble/1 kWh) and ten times higher than the cost of generating electricity at a hydroelectric power station (5-10 kopecks/1 kWh ).

Part of the reason for the high cost is that, unlike thermal and hydraulic power plants, geothermal power plants have a relatively small capacity. In addition, it is necessary to compare systems located in the same region and under similar conditions. For example, in Kamchatka, according to experts, 1 kWh of geothermal electricity costs 2-3 times less than electricity produced at local thermal power plants.

Indicators of the economic efficiency of a geothermal system depend, for example, on whether waste water needs to be disposed of and in what ways this is done, and whether combined use of the resource is possible. So, chemical elements and compounds extracted from thermal water can provide additional income. Let us recall the example of Larderello: the primary thing there was precisely chemical production, and the use of geothermal energy was initially of an auxiliary nature.

Geothermal energy forwards

Geothermal energy is developing somewhat differently than wind and solar. Currently she is significantly to a greater extent depends on the nature of the resource itself, which varies sharply by region, and the highest concentrations are tied to narrow zones of geothermal anomalies, usually associated with development areas (see “Science and Life” No. 9, 2013).

In addition, geothermal energy is less technologically intensive compared to wind and, especially, solar energy: geothermal station systems are quite simple.

IN general structure The geothermal component accounts for less than 1% of global electricity production, but in some regions and countries its share reaches 25-30%. Due to the connection to geological conditions, a significant part of geothermal energy capacity is concentrated in third world countries, where there are three clusters of the greatest development of the industry - the islands of Southeast Asia, Central America and East Africa. The first two regions are included in the Pacific “belt of fire of the Earth”, the third is tied to the East African Rift. It is most likely that geothermal energy will continue to develop in these belts. A more distant prospect is the development of petrothermal energy, using the heat of the layers of the earth lying at a depth of several kilometers. This is an almost ubiquitous resource, but its extraction requires high costs, so petrothermal energy is developing primarily in the most economically and technologically powerful countries.

In general, given the widespread distribution of geothermal resources and an acceptable level of environmental safety, there is reason to believe that geothermal energy has good development prospects. Especially with the growing threat of a shortage of traditional energy resources and rising prices for them.

From Kamchatka to the Caucasus

In Russia, the development of geothermal energy has a fairly long history, and in a number of positions we are among the world leaders, although the share of geothermal energy in the overall energy balance of the huge country is still negligible.

Two regions became pioneers and centers for the development of geothermal energy in Russia - Kamchatka and North Caucasus, and if in the first case we are talking primarily about electric power, then in the second - about the use of thermal energy of thermal water.

In the North Caucasus - in Krasnodar region, Chechnya, Dagestan - the heat of thermal waters was used for energy purposes even before the Great Patriotic War. In the 1980-1990s, the development of geothermal energy in the region, for obvious reasons, stalled and has not yet emerged from the state of stagnation. Nevertheless, geothermal water supply in the North Caucasus provides heat to about 500 thousand people, and, for example, the city of Labinsk in the Krasnodar Territory with a population of 60 thousand people is completely heated by geothermal waters.

In Kamchatka, the history of geothermal energy is connected, first of all, with the construction of GeoPPs. The first of them, still operating Pauzhetskaya and Paratunka stations, were built back in 1965-1967, while the Paratunka GeoPP with a capacity of 600 kW became the first station in the world with a binary cycle. This was the development of Soviet scientists S. S. Kutateladze and A. M. Rosenfeld from the Institute of Thermophysics SB RAS, who in 1965 received an author's certificate for the extraction of electricity from water with a temperature of 70 ° C. This technology subsequently became the prototype for more than 400 binary GeoPPs in the world.

The capacity of the Pauzhetskaya GeoPP, commissioned in 1966, was initially 5 MW and was subsequently increased to 12 MW. Currently, a binary unit is being built at the station, which will increase its capacity by another 2.5 MW.

The development of geothermal energy in the USSR and Russia was hampered by the availability of traditional energy sources - oil, gas, coal, but never stopped. The largest geothermal energy facilities at the moment are the Verkhne-Mutnovskaya GeoPP with a total capacity of power units of 12 MW, commissioned in 1999, and the Mutnovskaya GeoPP with a capacity of 50 MW (2002).

Mutnovskaya and Verkhne-Mutnovskaya GeoPPs are unique objects not only for Russia, but also on a global scale. The stations are located at the foot of the Mutnovsky volcano, at an altitude of 800 meters above sea level, and operate in extreme climatic conditions, where there is winter for 9-10 months of the year. The equipment of the Mutnovsky GeoPPs, currently one of the most modern in the world, was entirely created on domestic enterprises power engineering.

Currently, the share of Mutnovsky stations in the overall energy consumption structure of the Central Kamchatka energy hub is 40%. There are plans to increase capacity in the coming years.

Special mention should be made about Russian petrothermal developments. We don’t have large drilling centers yet, but we have advanced technologies for drilling to great depths (about 10 km), which also have no analogues in the world. Their further development will radically reduce the costs of creating petrothermal systems. The developers of these technologies and projects are N. A. Gnatus, M. D. Khutorskoy (Geological Institute of the Russian Academy of Sciences), A. S. Nekrasov (Institute of National Economic Forecasting of the Russian Academy of Sciences) and specialists from the Kaluga Turbine Plant. Currently, the petrothermal circulation system project in Russia is at the experimental stage.

Geothermal energy has prospects in Russia, although they are relatively distant: at the moment the potential is quite large and the position of traditional energy is strong. At the same time, in a number of remote areas of the country, the use of geothermal energy is economically profitable and is already in demand. These are territories with high geoenergy potential (Chukotka, Kamchatka, Kuril Islands - Russian part The Pacific “Fire Belt of the Earth”, the mountains of Southern Siberia and the Caucasus) and at the same time remote and cut off from the centralized energy supply.

Probably, in the coming decades, geothermal energy in our country will develop precisely in such regions.

Types of geothermal power plants by operating principle

Geothermal power plant (GeoTES) is a type of power plant that generates electrical energy from thermal energy from underground sources.

The operation scheme of a geothermal power plant is quite simple. Water, through specially drilled holes, is pumped deep underground, into those layers of the earth's crust that are naturally quite heated. Seeping into the cracks and cavities of hot granite, the water heats up until water vapor forms, and rises back through another, parallel well. After this, the hot water goes directly to the power plant, into the heat exchanger, and its energy is converted into electricity. This occurs through a turbine and generator, as in many other types of power plants. In another variant of a geothermal power plant, natural hydrothermal resources are used, i.e. water heated to a high temperature as a result of natural natural processes. However, the area of use of such resources is significantly limited by the presence of special geological areas. In this case, already heated water pumped from the bowels of the earth enters the heat exchanger. In another case, water, as a result of high geological pressure, rises on its own, through specially drilled holes. This is, let's say, general principle operation of a geothermal power plant, which is suitable for all their types. According to their technical design, geothermal power plants are divided into several types:

Hydrothermal steam geothermal power plants are power plants that use water already heated by nature;

Double-circuit geothermal power plant using water steam. Such power plants have a special double-circuit steam generator that allows generating “additional” steam. In other words, geothermal steam is used on the “hot” side of the steam generator, and secondary steam obtained from the supplied water is generated on the “cold” side;

Double-circuit geothermal power plant using low-boiling working substances. The scope of application of such power plants is the use of very hot (up to 200 degrees) thermal waters, as well as the use of additional water in hydrothermal steam deposits, which were mentioned above;

Currently, there are three schemes for generating electricity using geothermal resources:

Direct using dry steam

Indirect using steam

Mixed production scheme (binary cycle)

The type of transformation depends on the state of the medium (steam or water) and its temperature.

Dry steam power plants with a direct type of electricity production were the first to be developed. The very first geothermal power plant in the world worked precisely on this principle. Operation of this station began in the Italian town of Larderello (near Florence) back in 1911. Seven years earlier, on July 4, 1904, with the help of geothermal steam, a generator was powered here, which was able to light four light bulbs, after which the decision was made to build a power plant. Remarkably, the station in Larderello is still in operation today. To produce electricity at such geothermal power plants, steam coming through pipes from a well is passed directly through a turbine, which rotates a generator that produces electricity. (See Figure 1)

Figure 1 - Operating principle of a geothermal power plant operating on dry steam

A further development of geothermal power plants were power plants with an indirect type of electricity production, which are the most common today. They use hot underground water (temperatures up to 182 C) which are pumped at high pressure into installations on the surface. The hydrothermal solution is pumped into the evaporator to reduce the pressure, causing some of the solution to evaporate very quickly. The resulting steam drives the turbine. If there is liquid left in the tank, it can be evaporated in the next evaporator to obtain even more power. (See Figure 2)

At the moment, geothermal power plants with a mixed cycle of operation are becoming increasingly widespread. A new revolutionary technology for the construction of geothermal power plants, the Hot-Dry-Rock technology, which appeared several years ago, developed by the Australian company Geodynamics Ltd., significantly increases the efficiency of converting the energy of geothermal waters into electricity. The essence of this technology is as follows. Until very recently, the main principle of operation of all geothermal stations, which was the use of natural steam output, was considered unshakable in thermoenergetics. The Australians deviated from this principle and decided to create a suitable “geyser” themselves. To do this, they found a point in the desert in southeastern Australia where tectonics and isolated rocks create an anomaly that maintains very high temperatures in the area all year round. Therefore, if water is pumped through a well to such a depth, it will penetrate everywhere into the cracks of hot granite, expand them, simultaneously heat up, and then rise to the surface through another drilled well. After this, the heated water can be easily collected in a heat exchanger, and the energy obtained from it can be used to evaporate another liquid with a lower boiling point, the steam of which will power steam turbines. The water that has released geothermal heat will again be directed through the well to depth, and the cycle will thus repeat. (See Figure 3)

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"Geothermal power plants"

1. Geothermal power plants

The definition of geothermal energy is contained in its very name - it is the heat energy of the earth's interior. The layer of magma located under the earth's crust is a fiery liquid, most often silicate melt. According to calculations, the energy potential of heat at a depth of 10 thousand meters is 50 thousand times higher than the energy of the world's reserves of natural gas and oil.

Magma reaching the surface of the earth is called lava. The greatest " throughput»Earth eruptions of lava are observed at the boundaries of tectonic plates and where the earth's crust is quite thin. When lava comes into contact with the planet's water resources, the water begins to rapidly heat up, resulting in geyser eruptions, the formation of hot lakes and underwater currents. In short, natural phenomena arise whose properties can be used as an almost inexhaustible source of energy.

Sources of geothermal energy are practically inexhaustible. True, they are not widespread, although they have been found in more than 60 countries around the world. The largest number of active land volcanoes are located in the Pacific Volcanic Ring of Fire (328 out of 540 known).

The geothermal gradient in the well, which is used to get to underground energy, increases by 1 o C every 36 meters. The heat thus produced reaches the surface in the form of hot steam or water, which can be used directly to heat buildings or indirectly to generate electricity.

In practice, geothermal sources in different regions of the planet differ significantly from each other, which is why they have to be classified into dozens various characteristics such as average temperature, salinity, gas composition, acidity, etc. In plane practical application for production electrical energy The main classification of geothermal sources can be considered division into three main types:

· Direct - dry steam is used;

· Indirect - water vapor is used;

· Mixed (binary cycle).

Geothermal power plant scheme direct type

In the simplest direct-type geothermal power plants, steam is used to produce electricity, which comes from the well directly into the generator turbine. The very first geothermal power plant in the world worked precisely on this principle. Operation of this station began in the Italian town of Larderello (near Florence) back in 1911. Seven years earlier, on July 4, 1904, with the help of geothermal steam, a generator was powered here, which was able to light four light bulbs, after which the decision was made to build a power plant. Remarkably, the station in Larderello is still in operation today.

One of the largest operating geothermal power plants in the world, with a capacity of 1400 MW, is located in the Geysers region in Northern California (USA), and it also uses dry steam.

Scheme of geothermal power plant of indirect type

Geothermal power plants with an indirect type of electricity production are the most common today. They operate using hot underground water, which is pumped at high pressure into generating units installed on the surface.

In mixed-type geothermal power plants, in addition to underground water, an additional liquid (or gas) is used, whose boiling point is lower than that of water. They are passed through a heat exchanger, where geothermal water evaporates the second liquid, and the resulting vapor powers turbines. Such a closed system is environmentally friendly, since there are practically no harmful emissions into the atmosphere.

In addition, binary stations operate at fairly low source temperatures compared to other types of geothermal stations (100-190°C). This feature may make this type of geothermal power plants the most popular in the future, since in most geothermal sources the water temperature is below 190°C.

Mixed type geothermal power plant scheme

2. Use of geothermal sources in the world

The first geothermal power plant in the USSR was built in Kamchatka - the Pauzhetskaya Geothermal Power Plant, which began operating in 1967. The station's initial capacity was 5 MW; subsequently it was increased to 11 MW. The potential of hydrothermal deposits in Kamchatka is enormous. The heat reserves of geothermal waters here are estimated at 5000 MW. Full use of geothermal heat could solve the energy problem of the Kamchatka region and make it independent of imported fuel.

The most studied and most promising is the Mutnovskoye geothermal field, located 90 kilometers south of the city of Petropavlovsk-Kamchatsky. Back in 1986, an assessment carried out by the Institute of Volcanology of the Russian Academy of Sciences showed that the predicted resources of the field were 312 MW by thermal removal, and 450 MW by the volumetric method. The experimental-industrial Verkhne-Mutnovskaya Geothermal Power Plant with a capacity of 12 (3x4) MW has been operating since 1999. The installed capacity for 2004 is 12 MW.

View of the Mutnovskaya Geothermal Power Plant

The first stage of the Mutnovskaya Geothermal Power Plant with a capacity of 50 (2x25) MW was connected to the network on April 10, 2003; the installed capacity for 2007 is 50 MW, the planned capacity of the station is 80 MW.

Operating geothermal power plants provide up to 30% of the energy consumption of the central Kamchatka energy hub. It is pleasant to note that the thermomechanical equipment of the GeoTPP at the Mutnovskoye field was developed, created and supplied by domestic factories: turbines belong to KTZ OJSC, separators belong to PMZ OJSC, power fittings belong to ChZEM OJSC, etc.

The Kuril Islands are rich in heat reserves of the earth. In particular, on the island of Iturup, at the Ocean geothermal field, wells have already been drilled and a geothermal power plant is being built. There are reserves of geothermal heat on the southern island of Kunashir, and they are already being used to generate electricity and heat supply to the city of Yuzhno Kurilsk. On the island of Paramushir, which has reserves of geothermal water with temperatures ranging from 70 to 95°C, a GeoTS with a capacity of 20 MW is being built.

Significant reserves of geothermal heat (on the border with the Kamchatka region) are available in Chukotka. They are partially open and are used to heat nearby populated areas.

In Russia, the use of geothermal energy, except for Kamchatka, the Kuril Islands, Primorye, the Baikal region and the West Siberian region, is possible in the North Caucasus. Geothermal deposits with temperatures from 70 to 180°C, located at a depth of 300 to 5000 meters, have been studied here. In Dagestan, in 2000 alone, more than 6 million m 3 of geothermal water was extracted. In total, approximately half a million people in the North Caucasus are provided with geothermal water supply.

The largest geothermal power plant in Iceland (Nesjavellir) with a capacity of 120 MW

Today, the world leaders in geothermal power are the USA, the Philippines, Mexico, Indonesia, Italy, Japan, New Zealand and Iceland. Especially a shining example The use of geothermal energy is the latter state.

The island of Iceland appeared on the surface of the ocean as a result of volcanic eruptions 17 million years ago, and now its inhabitants enjoy their privileged position - approximately 90% of Icelandic homes are heated by underground energy.

In terms of electricity generation, there are five geothermal power plants with a total capacity of 420 MW, using hot steam from a depth of 600 to 1000 meters. Thus, 26.5% of Iceland's electricity is produced using geothermal sources.

Top-15 countries using geothermal energy (as of 2007)

	Power (MW)

Philippines
Indonesia



New Zealand
Iceland
Salvador
Costa Rica

Nicaragua

Papua New Guinea
Guatemala

3. Low-potential energy, but promising

geothermal power plant steam source

Geothermal sources can be divided into low, medium and high temperature. The first (with temperatures up to 150°C) are used, for the most part, for heating hot water - it is supplied through pipes to buildings (residential and industrial), swimming pools, greenhouses, etc. The latter (with a temperature above 150°C), containing dry or wet steam, are suitable for driving turbines of geothermal power plants (GeoTES).

A significant disadvantage of “hot” geothermal springs is their “selective” location in places of tectonic instability, as discussed above. If we take Russia, then the reserves of high-potential geothermal energy can only be used in Kamchatka, the Kuril Islands and in the region of the Caucasian mineral waters.

But the earth’s “boiler room” has not only high-potential, but also low-potential energy, the source of which is the soil of the surface layers of the earth (up to 400 m deep) or underground waters with a relatively low temperature. Low-grade heat can be used using heat pumps.

The thermal regime of the soil of the earth's surface layers is created under the influence of radiogenic heat coming from the bowels of the earth, as well as solar radiation falling on the surface. The intensity of incident solar radiation can vary depending on specific soil and climatic conditions ranging from several tens of centimeters to one and a half meters.

Low-grade heat can be effectively used for heating buildings, supplying hot water, and heating various structures (for example, the fields of open stadiums).

In the last decade, the number of systems using underground resources to supply buildings with heat and cold has increased significantly. Most of these systems are located in the USA. They are also available in Austria, Germany, Sweden, Switzerland, and Canada. There are only a few such systems in our country. IN European countries Heat pumps mainly heat rooms. In the USA, where systems air heating combined with ventilation, the air is not only heated, but also cooled.

If we talk about Russia, an example of the use of a low-potential source of thermal energy is located in Moscow, in the Nikulino-2 microdistrict. A heat pump system was built here to supply hot water to a multi-storey residential building. This project was implemented in 1998-2002 by the Ministry of Defense of the Russian Federation together with the Moscow government, the Ministry of Industry and Science of Russia, NP ABOK and OJSC Insolar-Invest as part of the Long-Term Energy Saving Program in Moscow.

There are two types of systems for using low-potential thermal energy of the earth: open systems and closed systems. The former use groundwater supplied directly to heat pumps, the latter use groundwater. Open systems are characterized by paired wells, with the help of which groundwater is not only extracted, but then returned back to the aquifers. Open systems make it possible to obtain large amounts of thermal energy at relatively low costs. However, the soil must be permeable, and the groundwater itself must have a suitable chemical composition to avoid corrosion and deposits on the walls of the pipes.

The world's largest geothermal heat pump system using groundwater energy is located in the American city of Louisville. With its help, the hotel and office complex is supplied with heat and cold. The system power is approximately 10 MW.

Closed systems are divided into vertical and horizontal.

Vertical ground heat exchanger

Vertical ground heat exchangers use low-grade thermal energy of the soil mass below the so-called “neutral zone” (10-20 meters from ground level). Such systems do not require large areas, and also do not depend on the intensity of solar radiation incident on the surface. They are suitable for almost all types of geological environments, except for soils with low thermal conductivity, such as dry sand or gravel.

In vertical ground heat exchangers, the coolant circulates through pipes (most often polypropylene or polyethylene) laid in vertical wells with a depth of 50 to 200 meters.

There are two types of vertical ground heat exchangers commonly used: U-shaped and coaxial. The first consists of two parallel pipes connected at the bottom. One or two pairs of such pipes are located in one well. The advantage of the U-shaped type is its relatively low manufacturing cost.

The second type of heat exchanger (also called concentric) consists of two pipes of different diameters, one of which is placed inside the other.

Systems with vertical ground heat exchangers are suitable for supplying buildings with both heat and cold. For a small building, one heat exchanger is enough, but for large buildings, several wells with vertical heat exchangers may be needed. An example of the latter is the heating and cooling supply system of the American college Richard Stockton College, which uses a record number of wells - 400 (130 meters deep). In Europe, the largest number of wells (154 wells with a depth of 70 meters) have been drilled for the heating and cooling system of the central office of the German Air Traffic Control.

Horizontal ground heat exchanger

Horizontal ground heat exchangers are usually created near the building, at a shallow depth, but always below the level of soil freezing in winter. In Europe, such heat exchangers are tightly connected (series or parallel) pipes. To save space, special types of heat exchangers have been created, for example, in the form of a spiral. It is promising to use water from tunnels and mines as a source of low-grade thermal energy, since the water temperature in them is constant. all year round and easily accessible.

The use of underground heat, both high-potential and low-potential, is considered extremely promising. This is especially true for providing buildings with warm and cooled air using low-grade heat.

According to the forecasts of the World Energy Committee (WEC), by 2020 the developed countries of the world will become quite active in supplying heat with heat pump systems. And here not only the “hot” bowels of the earth are suitable, but also the air and water of the seas and oceans. For example, in Sweden, where a station on six barges with a capacity of 320 MW is located near Stockholm, water from the Baltic Sea with a temperature of +4°C is used.

IN Russian Federation Huge reserves of natural gas, oil, coal and timber make it possible (for the time being) not to think too much about alternative energy sources. However, work on the development of geothermal sources has been carried out on its territory for several decades, which indicates an understanding of the importance of the issue. After all we're talking about about inexhaustible sources of heat and electricity, which, sooner or later, will become important, and perhaps the main suppliers of energy for all of humanity, and not just for individual countries.

4. Main advantages and disadvantages of geothermal energy

The current demand for geothermal energy as one of the types of renewable energy is due to: depletion of reserves organic fuel and the dependence of most developed countries on its imports (mainly oil and gas imports), as well as the significant negative impact of fuel and nuclear energy on the human environment and on wildlife. However, when using geothermal energy, its advantages and disadvantages should be fully taken into account.

The main advantage of geothermal energy is the possibility of its use in the form of geothermal water or a mixture of water and steam (depending on their temperature) for the needs of hot water and heat supply, for generating electricity or simultaneously for all three purposes, its practical inexhaustibility, complete independence from conditions environment, time of day and year. Thus, the use of geothermal energy (along with the use of other environmentally friendly renewable energy sources) can contribute significant contribution in solving the following urgent problems:

· Ensuring sustainable heat and electricity supply to the population in those areas of our planet where centralized energy supply is absent or is too expensive (for example, in Russia, Kamchatka, in areas Far North and so on.).

· Ensuring a guaranteed minimum energy supply to the population in areas of unstable centralized energy supply due to a shortage of electricity in energy systems, preventing damage from emergency and restrictive shutdowns, etc.

· Reducing harmful emissions from power plants in certain regions with difficult environmental conditions.

At the same time, in the volcanic regions of the planet, high-temperature heat that heats geothermal water to temperatures exceeding 140-150°C is most economically used to generate electricity. Underground geothermal waters with temperatures not exceeding 100°C are, as a rule, economically profitable to use for heat supply, hot water supply and other purposes in accordance with the recommendations given in Table. 1 .

Table 1

Please note that these recommendations, as geothermal technologies develop and improve, are being revised towards the use of geothermal waters with increasingly lower temperatures for the production of electricity. Thus, the currently developed combined schemes for the use of geothermal sources make it possible to use coolants with initial temperatures of 70-80°C for the production of electricity, which is significantly lower than those recommended in table1 temperatures (150°C and above). In particular, hydro-steam turbines have been created at the St. Petersburg Polytechnic Institute, the use of which at geothermal power plants makes it possible to increase the useful power of double-circuit systems (the second circuit is water steam) in the temperature range of 20-200°C by an average of 22%.

The efficiency of using thermal waters increases significantly when used in a complex manner. At the same time, in different technological processes it is possible to achieve the most full implementation thermal potential of water, including residual, and also to obtain valuable components contained in thermal water (iodine, bromine, lithium, cesium, kitchen salt, Glauber's salt, boric acid and many others) for their industrial use.

The main disadvantage of geothermal energy is the need to reinject waste water into the underground aquifer. Another disadvantage of this energy is the high mineralization of thermal waters in most deposits and the presence of toxic compounds and metals in the water, which in most cases excludes the possibility of discharging these waters into natural surface waters. water systems. The disadvantages of geothermal energy noted above lead to the fact that for the practical use of the heat of geothermal waters, significant capital costs are required for drilling wells, reinjection of waste geothermal water, as well as for the creation of corrosion-resistant thermal equipment.

However, due to the introduction of new, less expensive well drilling technologies, the use effective ways purification of water from toxic compounds and metals, capital costs for heat extraction from geothermal waters are continuously decreasing. In addition, it should be borne in mind that geothermal energy in Lately has made significant progress in its development. Thus, recent developments have shown the possibility of generating electricity at a temperature of the steam-water mixture below 80°C, which allows for a much wider use of geothermal power plants for generating electricity. In this regard, it is expected that in countries with significant geothermal potential, primarily in the United States, the capacity of geothermal power plants will double in the very near future.

Posted on Allbest.ru

First steps

In their daring search for new energy sources, scientists have considered many options. The possibilities of harnessing the energy of the tides of the World Ocean and transforming sunlight were studied. They also remembered the ancient windmills, equipping them with generators instead of stone millstones. Geothermal power plants are also of great interest, capable of generating energy from the heat of the lower hot layers of the earth's crust.

In the mid-sixties, the USSR did not experience a resource shortage, but the energy availability of the national economy, nevertheless, left much to be desired. The reason for lagging behind industrialized countries in this area was not a lack of coal, oil or fuel oil. The huge distances from Brest to Sakhalin made it difficult to deliver energy; it became very expensive. Soviet scientists and engineers proposed the most daring solutions to this problem, and some of them were implemented.

In 1966, the Pauzhetskaya geothermal power plant began operating in Kamchatka. Its power amounted to a rather modest figure of 5 megawatts, but this was quite enough to supply nearby settlements (the villages of Ozernovsky, Shumnoye, Pauzhetki, villages of the Ust-Bolsheretsky district) and industrial enterprises, mainly fish canning factories. The station was experimental, and today we can safely say that the experiment was a success. The Kambalny and Koshelev volcanoes are used as heat sources. The conversion was carried out by two turbine-generator units, initially 2.5 MW each. A quarter of a century later, the installed capacity was raised to 11 MW. The old equipment completely exhausted its service life only in 2009, after which a complete reconstruction was carried out, which included the laying of additional coolant pipelines. The experience of successful operation prompted energy engineers to build other geothermal power plants. There are five of them in Russia today.

How does it work

Initial data: deep in the earth's crust there is heat. It needs to be converted into energy, such as electricity. How to do it? The operating principle of a geothermal power plant is quite simple. Water is pumped underground through a special well, called an input or injection well (in English injection, that is, “injection”). A geological survey is required to determine the appropriate depth. Near the layers heated by magma, an underground flowing pool should ultimately form, playing the role of a heat exchanger. The water heats up greatly and turns into steam, which is supplied through another well (working or production) to the turbine blades connected to the generator axis. At first glance, everything looks very simple, but in practice, geothermal power plants are much more complicated and have various features designs due to operational problems.

Advantages of Geothermal Energy

This method of obtaining energy has undeniable advantages. Firstly, geothermal power plants do not require fuel, the reserves of which are limited. Secondly, operating costs are reduced to the costs of technically regulated work on the planned replacement of components and maintenance technological process. The payback period for investments is several years. Thirdly, such stations can conditionally be considered environmentally friendly. There are, however, sharp moments at this point, but more on them later. Fourthly, no additional energy is required for technological needs; pumps and other energy receivers are powered from extracted resources. Fifthly, the installation, in addition to working for its intended purpose, can desalinate the water of the World Ocean, on the shores of which geothermal power plants are usually built. There are pros and cons, however, in this case as well.

Flaws

In the photographs everything looks simply wonderful. The buildings and installations are aesthetically pleasing; there are no clouds of black smoke rising above them, only white steam. However, not everything is as wonderful as it seems. If geothermal power plants are located near populated areas, residents of the surrounding areas are annoyed by the noise produced by the enterprises. But this is only the visible (or rather, audible) part of the problem. When drilling deep wells, you can never predict what will come out of them. It may be a toxic gas mineral water(not always medicinal) or even oil. Of course, if geologists stumble upon a layer of mineral resources, then this is even good, but such a discovery may well completely change usual way of life lives of local residents, so permission to conduct even research work regional authorities are extremely reluctant to give. In general, choosing a location for a gas turbine power plant is quite difficult, because as a result of its operation, a ground failure may well occur. Conditions within the earth's crust change, and if the heat source loses its thermal potential over time, the construction costs will be in vain.

How to choose a place

Despite numerous risks, geothermal power plants are being built in different countries. Any method of generating energy has advantages and disadvantages. The question is how accessible other resources are. After all, energy independence is one of the foundations of state sovereignty. A country may not have mineral reserves, but have many volcanoes, like Iceland, for example.

It should be taken into account that the presence of geologically active zones is an indispensable condition for the development of the geothermal energy industry. But when deciding on the construction of such a facility, it is necessary to take into account safety issues, therefore, as a rule, geothermal power plants are not built in densely populated areas.

The next important point is the availability of conditions for cooling the working fluid (water). An ocean or sea coast is quite suitable as a location for a gas turbine power plant.

Kamchatka

Russia is rich in all types of natural resources, but this does not mean that there is no need to treat them with care. Geothermal power plants are being built in Russia, and more and more actively in recent decades. They partially meet the energy needs of remote areas of Kamchatka and the Kuril Islands. In addition to the already mentioned Pauzhetskaya GTPP, the 12-megawatt Verkhne-Mutnovskaya GTPP was put into operation in Kamchatka (1999). Much more powerful is the Mutnovskaya geothermal power plant (80 MW), located near the same volcano. Together they provide more than a third of the region's energy consumption.

Kuril Islands

The Sakhalin region is also suitable for the construction of geothermal energy production enterprises. There are two of them: Mendeleevskaya and Okeanskaya GTPP.

The Mendeleevskaya GTPP is designed to solve the problem of energy supply to the island of Kunashir, on which the urban-type settlement of Yuzhno-Kurilsk is located. The station did not get its name in honor of the great Russian chemist: that is the name of the island volcano. Construction began in 1993, and nine years later the enterprise was put into operation. Initially, the capacity was 1.8 MW, but after modernization and the launch of the next two stages it reached five.

In the Kuril Islands, on the island of Iturup, in the same 1993, another gas turbine power plant was founded, called “Okeanskaya”. It started operating in 2006, and a year later it reached its design capacity of 2.5 MW.

World experience

Russian scientists and engineers became pioneers in many branches of applied science, but geothermal power plants were still invented abroad. The world's first gas turbine power plant (250 kW) was Italian; it began operating in 1904; its turbine was rotated by steam coming from a natural source. Previously, such phenomena were used only for medicinal and resort purposes.

Currently, Russia’s position in the field of using geothermal heat cannot be called advanced either: an insignificant percentage of the electricity generated in the country comes from five stations. These alternative sources are most important to the Philippine economy: they account for one out of every five kilowatts produced in the republic. Other countries have also moved forward, including Mexico, Indonesia and the United States.

In the vastness of the CIS

The level of development of geothermal energy is influenced to a greater extent not by the technological “advancement” of a particular country, but by the awareness of its leadership urgent need in alternative sources. There is, of course, “know-how” regarding methods of combating scale in heat exchangers, methods of controlling generators and other electrical parts of the system, but all this methodology has long been known to specialists. In recent years, many post-Soviet republics have shown great interest in the construction of geothermal power plants. In Tajikistan, areas that represent the country’s geothermal wealth are being studied; the construction of a 25-megawatt Dzhermakhbyur station in Armenia (Syunik region) is underway; corresponding research is being conducted in Kazakhstan. The hot springs of the Brest region have become a subject of interest for Belarusian geologists: they began test drilling of the two-kilometer Vychulkovskaya well. In general, geoenergy most likely has a future.

However, the Earth’s heat must be handled with care. This natural resource is also limited.

Introduction

1. Geothermal energy

Conclusion

Bibliography

Introduction

The power supply of society is its basis scientific and technological progress, the basis for the development of production forces. Its compliance with social needs is the most important factor of economic growth. Developing world economy requires a constant increase in the power supply of production. It must be reliable and designed for the long term. The energy crisis of 1973-1974 in capitalist countries demonstrated that this is difficult to achieve based only on traditional energy sources (oil, coal, gas). It is necessary not only to change the structure of their consumption, but also to more widely introduce non-traditional, renewable energy sources (NRES). These include solar, geothermal, wind energy, as well as biomass and ocean energy. This also includes nuclear energy, but at the current stage of its development this seems extremely vague.

Unlike fossil fuels, unconventional types of energy are not limited by geologically accumulated reserves. This means that their use and consumption does not lead to irreversible depletion of resources. The main factor when assessing the feasibility of using renewable energy sources is the cost of the energy produced in comparison with the cost of energy obtained by conventional methods. Non-traditional sources are becoming especially important to satisfy local energy consumers.

Of the above alternative energy sources, one of the most common, technologically advanced, in demand and, importantly, cheap is geothermal energy. Thanks to these qualities, since the beginning of the 20th century it has become widespread even relative to other alternative energy sources, which gives us the right to hope that it will take its rightful place in the development of alternative energy in the current and possibly subsequent centuries.

1. Geothermal energy

World potential. development prospects

Geothermal energy is energy obtained from the natural heat of the Earth, formed due to the splitting of radionuclides as a result of physical and chemical processes in the bowels of the earth.

According to the classification of the International Energy Agency, geothermal energy sources are divided into 5 types:

-deposits of geothermal dry steam - relatively easy to develop, but quite rare; however, half of all geothermal power plants operating in the world use heat from these sources;

-sources of wet steam (mixtures of hot water and steam) are more common, but when developing them, it is necessary to solve the issues of preventing corrosion of geothermal power plant equipment and environmental pollution (removal of condensate due to its high degree of salinity);

-deposits of geothermal water (contain hot water or steam and water) - are so-called geothermal reservoirs, which are formed as a result of filling underground cavities with water from atmospheric precipitation, heated by nearby magma;

-dry hot rocks heated by magma (at a depth of 2 km or more) - their energy reserves are the greatest;

-magma, which is molten rock heated to 1300°C. Heat arises there primarily due to the decay of natural radioactive elements such as uranium and potassium.

However, the Earth's heat is very "dissipated", and in most areas of the world only a very small part of such energy can be used profitably by man. Of these, usable geothermal resources account for only 1% of the total heat capacity of the upper 10 km of the earth's crust, or 137 trillion. that. t (tons of standard fuel). But this amount of geothermal energy can meet the needs of humanity for a long time. Areas of high seismic activity around the edges of continental plates are the best places to build geothermal power plants because the crust in such zones is much thinner. That is why the most promising geothermal resources are located in areas of volcanic activity. Unfortunately, humanity has not yet learned to use the energy of volcanoes for peaceful purposes. But the hidden, at first glance imperceptible, manifestations of the energy of the earth’s interior, considered below, have long been effectively used by people to obtain thermal, and over the past almost 100 years, electrical energy.

In direct use, high-temperature heat that heats geothermal water to temperatures not exceeding 100°C is usually used for heating, hot water supply and other similar purposes. The practice of direct heat use is widespread at tectonic plate boundaries, such as in Iceland, Japan, and Far East. Geysers are an example of such a heat source. In such cases, the water supply is installed directly into deep wells. At temperatures of geothermal waters exceeding 140 - 150°C, when water near the surface of the earth is heated to a boiling point, as a result of which it breaks out to the surface in the form of water vapor, it is economically most profitable to use geothermal energy to generate electricity (See Table 1).

Table 1 - Correlations between temperature values and methods of using geothermal energy

Water temperature value, °С Scope of application More than 150 Electricity generation Less than 100 Building heating systems About 60 Hot water supply systems Less than 60 Heat supply for greenhouses, geothermal refrigeration units, etc.

A group of experts from the World Geothermal Energy Association, which assessed the reserves of low- and high-temperature geothermal energy for each continent, obtained the following data on the potential of various types of geothermal sources on our planet (See Table 2).

Table 2 - Geothermal potential of low and high temperature energy

Name of continent Type of geothermal source: High temperature, used for electricity production, TJ/year Low temperature, used as heat, TJ/year (lower limit) traditional technologies traditional and binary technologies Europe 18303700 >370Asia29705900 >320Africa12202400 >240North America13302700 >120Latin America28005600 >240Oceania10502100 >110World potential1120022400 >1400

As can be seen from this table, the potential of geothermal energy sources is simply enormous. However, it is used extremely little: the installed capacity of geothermal power plants worldwide at the beginning of the 1990s was only about 5,000, and at the beginning of the 2000s - about 6,000 MW, significantly inferior in this indicator to most power plants operating on other renewable energy sources . And the generation of electricity at geothermal power plants during this period of time was insignificant. This is evidenced by the following data. In the structure of global electricity production, renewable energy sources provided 19% of global electricity production in 2000. At the same time, despite the significant pace of development, geothermal, solar and wind energy accounted for less than 3% of the total use of energy obtained from renewable sources in 2000.

However, geothermal power generation is currently developing at an accelerated pace, not least due to the galloping increase in the cost of oil and gas. This development is largely facilitated by government programs adopted in many countries around the world that support this direction of development of geothermal energy.

It should be noted that geothermal resources have been explored in 80 countries of the world and are actively used in 58 of them. The largest producer of geothermal electricity is the United States, where geothermal electricity, as one of the alternative energy sources, has special government support. In the USA in 2005, geothermal power plants generated about 16 billion kW ⋅h of electricity in such major industrial areas as the Great Geysers area, located 100 km north of San Francisco (1360 MW installed capacity), the northern part of the Salt Sea in central California (570 MW installed capacity), Nevada (235 MW installed capacity ) etc. Geothermal power industry is also rapidly developing in a number of other countries, including: in the Philippines, where at the beginning of 2003, 1930 MW of electric power was installed at geothermal power plants, which made it possible to meet about 27% of the country's electricity needs; in Italy, where geothermal power plants with a total capacity of 790 MW were in operation in 2003; in Iceland, where there are five cogeneration geothermal power plants with a total electrical capacity of 420 MW, generating 26.5% of all electricity in the country; in Kenya, where three geothermal power plants with a total electrical capacity of 160 MW operated in 2005 and plans were developed to increase this capacity to 576 MW. For a list of leading countries where geothermal power is developing at an accelerated pace, see Table 3.

Table 3 - Top 15 countries using geothermal energy (2007 data)

CountryPower (MW) USA2687Philippines1969.7Indonesia 992Mexico953Italy810.5Japan535.2New Zealand471.6Iceland 421.2El Salvador204.2Costa Rica162.5Kenya128.8Nicaragua87.4Russia79Papua New Guinea i56Guatemala53

Unfortunately, Russia is not even among the top ten producers of electrical and thermal energy from geothermal sources, while geothermal energy reserves in Russia are estimated to be 10-15 times higher than the country's fossil fuel reserves.

Characterizing the development of the global geothermal power industry as an integral part of renewable energy in the longer term, we note the following. According to forecasts, in 2030 a slight decrease (up to 12.5% compared to 13.8% in 2000) in the share of renewable energy sources in global energy production is expected. At the same time, the energy of the sun, wind and geothermal waters will develop at an accelerated pace, increasing annually by an average of 4.1%, however, due to the “low” start, their share in the structure of renewable sources will remain the smallest in 2030.

The experience accumulated by various countries (including Russia) relates mainly to the use of natural steam and thermal waters, which remain the most realistic base for geothermal energy. However, its large-scale development in the future is possible only with the development of petrogeothermal resources, i.e. thermal energy of hot rocks, the temperature of which at a depth of 3 - 5 km usually exceeds 100°C.

However, when using geothermal energy, its advantages and disadvantages should be fully taken into account. The main advantages of geothermal energy are;

-the possibility of its use in the form of geothermal water or a mixture of water and steam (depending on their temperature) for the needs of hot water and heat supply, as well as for generating electricity or simultaneously for both;

-almost complete safety for the environment. CO quantity 2, released during the production of 1 kW of electricity from high-temperature geothermal sources, ranges from 13 to 380 g (for example, for coal it is 1042 g per 1 kWh);

-economic efficiency is several times higher than traditional types of electricity generation, as well as other types of renewable energy sources;

-its practical inexhaustibility;

-complete independence in work from environmental conditions, time of day and year;

-utilization rate exceeds 90%;

Thus, the use of geothermal energy (along with the use of other environmentally friendly renewable energy sources) can make a significant contribution to solving the following pressing problems;

-ensuring sustainable heat and electricity supply to the population in those areas of our planet where centralized energy supply is absent or is too expensive (for example, in Russia in Kamchatka, in the Far North, etc.);

-ensuring a guaranteed minimum energy supply to the population in areas of unstable centralized energy supply due to a shortage of electricity in energy systems, preventing damage from emergency and restrictive shutdowns, etc.;

-reduction of harmful emissions from power plants in certain regions with difficult environmental conditions;

These advantages lead to the fact that geothermal energy, despite its youth (it has only a 100-year history), is now developing all over the world;

The main disadvantages of geothermal energy are:

the need to reinject waste water into the underground aquifer;

-high mineralization of thermal waters of most deposits, the presence of toxic compounds and metals in the water, which in most cases excludes the possibility of discharging these waters into natural water systems located on the surface;

-limited areas of sources of such energy;

-low temperature potential of the coolant;

-limited industrial experience in operating stations;

Also, the development of geothermal energy is stopped by the high cost of installations, as well as lower energy output compared to gas or oil wells. On the other hand, they can be used much longer than deposits of traditional sources.

The disadvantages of geothermal energy noted above lead to the fact that for the practical use of the heat of geothermal waters, significant capital costs are required for drilling wells, reinjection of waste geothermal water, as well as for the creation of corrosion-resistant thermal equipment.

However, due to the introduction of new, less expensive technologies for drilling wells, and the use of effective methods for purifying water from toxic compounds and metals, capital costs for collecting heat from geothermal waters are continuously decreasing. In addition, it should be borne in mind that geothermal energy has recently made significant progress in its development. Thus, recent developments have shown the possibility of generating electricity at a temperature of the steam-water mixture below 80 º C, which makes it possible to use geothermal power plants much more widely for generating electricity. In this regard, it is expected that in countries with significant geothermal potential, primarily in the United States, the capacity of geothermal power plants will double in the very near future.

geothermal energy russia power plant

2. Geothermal power plants

Types of geothermal power plants by operating principle

Geothermal power plant (GeoTES) is a type of power plant that generates electrical energy from thermal energy from underground sources.

The operation scheme of a geothermal power plant is quite simple. Water, through specially drilled holes, is pumped deep underground, into those layers of the earth's crust that are naturally quite heated. Seeping into the cracks and cavities of hot granite, the water heats up until water vapor forms, and rises back through another, parallel well. After this, the hot water goes directly to the power plant, into the heat exchanger, and its energy is converted into electricity. This occurs through a turbine and generator, as in many other types of power plants. In another variant of a geothermal power plant, natural hydrothermal resources are used, i.e. water heated to a high temperature as a result of natural processes. However, the area of use of such resources is significantly limited by the presence of special geological areas. In this case, already heated water pumped from the bowels of the earth enters the heat exchanger. In another case, water, as a result of high geological pressure, rises on its own, through specially drilled holes. This, so to speak, is the general principle of operation of a geothermal power plant, which is suitable for all types. According to their technical design, geothermal power plants are divided into several types:

-geothermal power plants using steam-hydrotherms are power plants that use water already heated by nature;

-double-circuit geothermal power plant using water steam. Such power plants have a special double-circuit steam generator that allows generating “additional” steam. In other words, geothermal steam is used on the “hot” side of the steam generator, and secondary steam obtained from the supplied water is generated on the “cold” side;

-double-circuit geothermal power plant using low-boiling working substances. The scope of application of such power plants is the use of very hot (up to 200 degrees) thermal waters, as well as the use of additional water in hydrothermal steam deposits, which were mentioned above;

Currently, there are three schemes for generating electricity using geothermal resources:

-direct using dry steam

-indirect using steam

The type of transformation depends on the state of the medium (steam or water) and its temperature.

Figure 1 - Operating principle of a geothermal power plant operating on dry steam

A further development of geothermal power plants were power plants with an indirect type of electricity production, which are the most common today. They use hot underground water (temperatures up to 182 ° C) which are pumped at high pressure into installations on the surface. The hydrothermal solution is pumped into the evaporator to reduce the pressure, causing some of the solution to evaporate very quickly. The resulting steam drives the turbine. If there is liquid left in the tank, it can be evaporated in the next evaporator to obtain even more power. (See Figure 2)

Figure 2 - Operating principle of a geothermal power plant with an indirect type of energy production

Figure 3 - Operating principle of a geothermal power plant with a binary cycle

3. Development of geothermal energy in Russia

⋅h. Russia, unfortunately, is not even among the top ten producers of electrical and thermal energy from geothermal sources, while geothermal energy reserves are estimated to be 10-15 times higher than fossil fuel reserves. Almost throughout the entire country there are reserves of geothermal heat with temperatures ranging from 30 to 200 ° C. To date, about 4,000 wells have already been drilled to a depth of 5,000 m, allowing for large-scale implementation modern technologies for local heat supply throughout the country. The potential thermal resources of the upper layers of the Earth, to a depth of 100-200 m, are estimated at 400-1000 million tons of standard fuel per year.

According to the Institute of Volcanology of the Far Eastern Branch of the Russian Academy of Sciences, the geothermal resources of Kamchatka alone are estimated at 5000 MW, which will provide the region with electricity and heat for 100 years. That's why Special attention is devoted to the development of geothermal energy in this region. A program for creating a geothermal energy supply for Kamchatka has already been developed and is being implemented, as a result of which about 900 tons of fuel equivalent will be saved annually. T.

According to Research Techart forecasts, the share of geothermal energy in Russia by 2020 may reach 0.3% in the total energy balance. The installed capacity will be 750 MW and up to 5 billion kWh of electricity can be generated through the thermal resources of the earth. The largest increase in installed capacity is expected in the period from 2015 to 2020. The forecast dynamics of the commissioning of geothermal capacities is presented in Figure 4. The development of the industry will also be facilitated by an increase in the volume of investments. Thus, by 2020, about 60 billion rubles will be invested in the construction of new geothermal facilities. (Figure 5)

Power, MW

Period

Figure 4 - Projected dynamics of commissioning of new capacities, MW. Billion rub.

Period

Figure 5 - Assessment of capital investments in the creation of geothermal energy facilities, billion rubles.

At the same time, considering the current and advanced production electricity based on renewable sources, it should be noted that geothermal energy by the beginning of the century of the total amount of generated electricity did not exceed 0.15% and only by 2010, although it will increase by a third, will not exceed 0.2% with the total generation at the level 7 TWh. In accordance with the Energy Strategy of Russia until 2020, it is planned to increase heat consumption in the country by at least 1.3 times, and the share of decentralized heat supply will increase from 28.6% in 2000 to 33% in 2020. However, until recently, The scale of geothermal energy use in the country was very modest. The use of geothermal energy in remote regions of Russia, in particular in Kamchatka, seems especially relevant. In Kamchatka, at the Paratunskoye field, a pilot industrial geothermal power plant with a capacity of about 500 kW was created in 1967 - this was the first experience in generating electricity using geothermal heat in Russia. At the same time, the first industrial generation of electricity in Russia began at the Pauzhetskaya geothermal power plant. The latter still works and provides the cheapest electricity in Kamchatka.

When, in a market economy, the price of fuel oil began to rise sharply, it turned out that the most expensive electricity in Russia was Kamchatka, which was entirely dependent on the so-called northern supply. There was a time when 1 kWh cost almost 30 cents. For comparison: the world price is 6 cents, in Russia - 1.5-3. In 1994, JSC Geotherm and JSC Geotherm-M were organized, and from that moment the implementation of the project began. Current development of geothermal energy in Kamchatka time is running not as active as required by the economy and environmental situation in the region. There are several reasons: the lack of emphasis on geothermal energy in the region’s energy development strategy, the significant debts of Kamchatskenergo JSC for long-term supplies of fuel oil.

According to JSC "Geotherm - M", Russia's geothermal resources are distributed as follows: all three Russian geothermal power plants are located on the territory of Kamchatka, the total energy potential of steam-water thermals is estimated at 1 GW of operating electrical power, but is realized only in the amount of 76.5 MW of installed capacity (2004) and about 420 million kW/hour of annual output (2004). The Mutnovskaya power plant, the largest in the region, is located 120 kilometers from the city of Petropavlovsk-Kamchatsky at an altitude of 1 km above sea level, at the foot of the volcano of the same name. The Mutnovskoye field consists of the Verkhne-Mutonovskaya GeoTPP, with an installed capacity of 12 MW (2007) and a production of 52.9 million kWh/year (2007) (81.4 in 2004) and the Mutonovskaya GeoTPP with a capacity of 50 MW (2007) and a production of 360 .7 million kWh/year (2007) (276.8 in 2004)

According to the International Energy Agency (IEA), the construction cost of these plants was $150 million. To finance the project, RAO UES received a loan of $100 million from the European Bank for Reconstruction and Development. According to experts, production capacity Mutnovskaya Geothermal Power Plant will grow to 250 MW in the coming years.

The Pauzhetsky field is located near the Koshelev and Kambalny volcanoes - Pauzhetskaya Geothermal Power Plant with a capacity of 14.5 MW e (2004) and a production of 59.5 million kWh. At the Pauzhetskaya Geothermal Power Plant with a capacity of 11 MW, only separated geothermal steam from the steam-water mixture obtained from geothermal wells is used in steam turbines. A large amount of geothermal water (about 80% of the total consumption of PVA) with a temperature of 120°C is discharged into the spawning river Ozernaya, which leads not only to the loss of the thermal potential of the geothermal coolant, but also significantly worsens the ecological condition of the river. It is proposed to use the heat of waste geothermal water to generate electricity by creating a double-circuit power plant using a low-boiling working fluid. The waste water flow at the existing Pauzhetskaya Geothermal Power Plant is sufficient for a 2 MW power plant. The temperature of the discharge water is reduced to 55°C, thereby significantly reducing thermal pollution of the river.

In the Stavropol Territory, at the Kayasulinskoye field, the construction of an expensive experimental Stavropol Geothermal Power Plant with a capacity of 3 MW was started and suspended.

There is a project for Ocean Geothermal Power Plant with a capacity of 34.5 MW and an annual output of 107 million kWh. Currently, electricity supply to the city of Kurilsk and the villages of Reidovo and Goryachiye Klyuchi is carried out using diesel power plants, and heat supply is provided using coal-fired boiler houses. Diesel fuel is imported during a short navigation period - to the island. Iturup does not have its own fuel. In recent years, due to financial difficulties, the import of fuel to the island has sharply decreased; Electricity is supplied to the population for 2-3 hours a day. At the same time, the island has the richest reserves of high-potential geothermal energy sources on an island scale, which, moreover, have mostly already been explored. About 75-80 billion rubles were spent on hydrogeological exploration and R&D for the creation of geothermal power plants. at current prices. The cost of electricity at geothermal power plants is more than two times lower than at diesel power plants. Imported fuel will be displaced at the rate of 2.5-3 thousand tons. t./year/MW. The environmental situation on the island will improve.

There is a 2.6 MW geothermal power plant in Kunashir, and several geothermal power plants with a total capacity of 12-17 MW are planned. In the Kaliningrad region, it is planned to implement a pilot project for geothermal heat and electricity supply to the city of Svetly based on a binary geothermal power plant with a capacity of 4 MW. Currently, geothermal energy sources provide up to 25 percent of Kamchatka's total energy consumption, which significantly helps reduce the peninsula's dependence on expensive imported fuel oil. The largest hydrothermal steam deposits in Kamchatka are located in mountainous areas with an unfavorable climate. The average annual temperature is negative, the snow depth is up to 10 m. This significantly complicates and increases the cost of the construction and operation of geothermal power plants.

Employees of ENIN, JSC "Nauka" and NUC MPEI proposed a geothermal power plant project that allows at least one and a half times to increase their useful power and increase reliability.

As is known, the steam-water mixture coming from geothermal wells has a complex chemical composition. The salt content in the water phase is up to 2 g/l, including a lot of silicic acid, in the steam there is a significant amount of non-condensable gases, including hydrogen sulfide. This limits the possibility of deep use of the thermal potential of the geothermal coolant in the traditional cycle of GeoTES with condensing steam turbines, not allowing additional steam to be obtained by expansion of water and deep vacuum in the condenser. Strong winds, frost, heavy snowfalls, combined with high humidity, create a threat of ice formation in wet cooling towers usually used at geothermal power plants, which can lead to the shutdown of power units and even to the destruction of cooling towers.

At the proposed combined cycle geothermal power plants, these problems are largely solved. If you use steam turbines with close to atmospheric back pressure and direct the exhaust steam to a condenser, which is also a steam generator for the lower circuit of the station with turbines on a low-boiling, non-freezing working fluid, then the total electricity generation can be significantly increased by reducing the temperature of heat removal from the cycle. The steam of the low-boiling working fluid is condensed in an air condenser, so the useful power of the station in winter increases significantly along with the increase in the demand for electricity. In addition, there is no steam consumption for ejectors to remove non-condensable gases; it is also possible to partially use the heat of geothermal water to superheat the steam of a low-boiling working fluid. Winter operation of the station is facilitated, since there is no open contact of water with air, and the water temperature in heat exchangers and pipelines does not fall below 60°C.

Combined geothermal power plants are already operating abroad, but in areas with a tropical climate, where their effectiveness cannot be fully realized due to high temperatures air. For the northern regions, the above advantages of such stations provide great prospects for their use. In the international tender currently underway for the construction of the first stage of the Mutnovskaya Geothermal Power Plant, a combined cycle station is considered as one of the possible options.

Unfortunately, in Russia there is no domestic serial equipment for power plants using low-boiling working fluid, so only foreign companies can be real suppliers. This leads to an increase in the required capital investments in construction and operating costs. In order to speed up the creation of combined geothermal power plants in Kamchatka and stimulate the work of domestic equipment manufacturers, Geotherm JSC plans to build the fourth unit of the Verkhne-Mutnovskaya geothermal power plant using a combined thermal scheme in the near future.

The development of geothermal energy in Russia will largely help solve the problem of electrification of sparsely populated areas and increasing the reliability of power supply to that part of consumers for whom centralized energy supply is economically unacceptable. Without the use of renewable sources, it is impossible to satisfactorily solve the energy supply of the Far North; areas not connected by networks common use; increase the reliability and quality of power supply to regions that are deficient in electrical energy and organic resources to a civilized level; improve the environmental situation in the country, ensure emergency power supply, special facilities, as well as educational, cultural, and service facilities.

Conclusion

The Earth's heat is very "dissipated" and in most areas of the world only a very small part of such energy can be used profitably by man. Of these, usable geothermal resources account for only 1% of the total heat capacity of the upper 10 km of the earth's crust, or 137 trillion. tons of standard fuel. But this amount of geothermal energy can meet the needs of humanity for a long time. Areas of high seismic activity around the edges of continental plates are the best places to build geothermal power plants because the crust in such zones is much thinner. That is why the most promising geothermal resources are located in areas of volcanic activity.

In the structure of global electricity production, renewable energy sources provided 19% of global electricity production in 2000. At the same time, despite the significant pace of development, geothermal, solar and wind energy accounted for less than 3% of the total use of energy obtained from renewable sources in 2000. However, geothermal power generation is currently developing at an accelerated pace, not least due to the galloping increase in the cost of oil and gas. This development is largely facilitated by government programs adopted in many countries around the world that support this direction of development of geothermal energy.

Geothermal energy, including geothermal power plants, is one of the most promising types of alternative energy sources. The current demand for geothermal energy as a type of renewable energy is due, first of all, to the depletion of fossil fuel reserves and the dependence of most developed countries on its imports (mainly oil and gas imports), as well as the significant negative impact of traditional energy on the environment.

Today, geothermal power plants in the world produce about 54,613 GWh of energy per year. The total capacity of existing geothermal heating systems is estimated at 75,900 GW ⋅h. Russia, unfortunately, is not even among the top ten producers of electrical and thermal energy from geothermal sources, while geothermal energy reserves are estimated to be 10-15 times higher than fossil fuel reserves.

Now, due to the introduction of new, less expensive technologies for drilling wells, and the use of effective methods for purifying water from toxic compounds and metals, capital costs for collecting heat from geothermal waters are continuously decreasing.

In addition, it should be borne in mind that geothermal energy has recently made significant progress in its development. Thus, recent developments have shown the possibility of generating electricity at a temperature of the steam-water mixture below 80 º C, which makes it possible to use geothermal power plants much more widely for generating electricity.

In this regard, it is expected that in countries with significant geothermal potential, primarily in the United States, the capacity of geothermal power plants will double in the very near future.

Bibliography

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Maksimov, I.G. Alternative energy sources [Text] / I.G. Maksimov - M.: "Eco-Trend", 2005. - 387 p.

Feofanov, Yu.A. Geothermal power plants [Text] / Yu.A. Feofanov - M.: "Eco-Trend", 2005. - 217 p.

Alkhasov, A.B. Geothermal energy: problems, resources, technologies [Text] / A.B. Alkhasov - M.: "Fizmatlit", 2008. - 376 p.