Geothermal power plants are at a stage of strong development. According to a 2005 study by Italian electricity grid company ENEL, geothermal power plants produce 8,900 megawatts of electricity in 24 countries. At the same time, the majority (32%) of this type of energy is produced in the United States.
The first geothermal power plant appeared in Larderello (Italy) in 1904. A team of scientists led by Prince Piero Ghinori Conti has developed a way to use steam from local sources to spin generator turbines. This power plant is still in operation today. In 1950, the New Zealand government began exploring the possibility of using Wairakea's geothermal springs to generate electricity. Wairakei is home to geysers, hot springs and mud pools. In 1958, the Wairakea geothermal power station, the second in the world, opened. The largest geothermal power plant is called The Geysers, located near the city of Santa Rosa in California. This station opened in 1960. Although there are no geysers at the station, there are many steam wells in the region. The geysers produce about 750 megawatts of electricity - enough to power a city like San Francisco.
Since 2000, geothermal energy production in France, Russia and Kenya has tripled. In countries such as the Philippines, Iceland, and El Salvador, 25% of electricity is obtained from geothermal sources, in Tibet - 30%.
A geothermal power plant is based on one of three processes. Direct steam or dry steam heating power plants are built in areas where the main source of geothermal activity is steam wells. Compressed steam from the well passes through pipes to the turbines. The turbine consists of a series of inclined blades mounted on a central shaft. Compressed steam passing through the turbine rotates it. The rotating turbine turns on the generator. The water cools and flows back into the ground. Larderello and Geysers work this way.
A pulsed steam power plant uses water at temperatures above 180 degrees Celsius to produce steam. Using a special technique, hot water under high pressure comes from great depths and is sprayed into containers with low pressure. Water instantly turns into steam. The high-pressure steam turns turbines in a generator that produces electricity. The water cools and flows back underground.
Double-cycle power plants use medium-temperature thermal water, heated from 107 to 182 degrees. Thermal water enters a heat exchanger through which a liquid flows, having a boiling point lower than that of water. The heat turns the liquid into steam, which turns turbines. Thermal water does not come into contact with the turbines; it flows back underground from the heat exchanger. Most geothermal resources are at medium temperature, so the future plans are to build mainly dual-cycle power plants.
Problems
Geothermal power plants raise questions about geothermal energy. One of these issues is the failure of the ground during the initial intake of water or steam. This can be a serious problem. On Wairakei, after the station began operating, the ground dropped by 13 m. This problem still exists on Wairakei. At new stations, water is quickly returned to maintain pressure and groundwater levels.
Double-cycle geothermal power plants do not emit any gases. However, steam power plants emit small amounts of CO2, the amount emitted depends on the composition of the water. A small amount of hydrogen sulfide is also released, not enough to form acid rain. Since groundwater contains dissolved sulfur, the operation of the station is accompanied by an unpleasant odor. In the US, geothermal power plants must filter out the hydrogen sulfide in their emissions by burning it or converting it to sulfur dioxide. The sulfur dioxide can later be dissolved or converted into sulfuric acid and sold. The salts and minerals that are filtered out of the water are pumped back into the well. Some of the waste is processed to produce useful minerals.
With the flow
Researchers are working to harness the Earth's heat by drilling into the warm layers of the Earth's crust close to the mantle. However, these ideas require drilling much deeper wells than current technical capabilities allow.
Biomass energy
Biomass- one of the fastest growing renewable energy sources. What is biomass? How is it used? And how does it replace the oil, natural gas and coal we depend on so much?
Name biomass speaks for itself: bio logical substances - plants in large volumes, (in mass). Biological fuels take energy from plants and convert it into a form that can be used to generate electricity or fuel cars.
Here's how it works. During photosynthesis, hydrocarbons appear in plants: sugar and starch. Hydrocarbons are organic components obtained from coal and hydrogen. These components store energy in the bonds that hold them together. The stored energy is released when the plants are eaten or, more importantly for us, when the plants are buried. Oxygen in the air reacts with carbon in plants to release energy, water, and carbon dioxide (CO2). This energy is used to convert water into steam. The steam turns turbines that produce electricity.
There is another way to release plant energy. The fermentation process converts sugar in plants into alcohol. Alcohol, in liquid or gaseous form, can be burned to produce energy. Fuel obtained from biomass in this way is called biological.
One of the greatest strengths of biomass is that it comes from plants that are easily renewable—they can be grown again. The potential for using biomass is very high. Since the factory uses the same hydrogen and carbon elements as fuel, biomass can replace oil and become what are called social chemicals. These substances are used to make many products such as plastics, paints and glues. However, biomass is currently an underutilized renewable energy source.
What is biomass?
Biomass- a very broad term that refers to any type of plant waste. This includes wood and agricultural waste, as well as some types of grains grown specifically for use as biofuels.
Thousands of years ago, someone deliberately put wood in the fire to get heat. This was the first use of biofuel. Since then, wood has been used as fuel for a very long time. Residents of many countries still heat their homes and cook food by burning wood. Although widely available, wood is a relatively inefficient fuel when burned in a fire. When used as biomass, wood is used as efficiently as possible.
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People burn wood and plant waste to obtain energy. Waste comes from industry: deforestation, construction, paper production, farming, solid waste from city landfills, and methane, a gas produced in landfills. Some types of herbs can also be used as biofuels after fermentation.
How is biofuel used?
All over the world, biofuels - mainly wood products - are burned together with coal in thermal power plants. This process is called co-combustion because instead of one type of fuel, two are used. Co-combustion is used in various types of coal boilers. To get the most out of biofuels, only minor changes need to be made to the boiler design. The most effective way is to add biofuel after spraying the coal.
In 2005, 4% of energy in the European Union was obtained using biofuels. The leaders in this were Finland and Sweden: 16 and 20% of energy, respectively. Biowaste projects are being developed in Asia to replace the hitherto widely used wood. Biofuel projects are also being developed in Africa.
In 2002, the US bioenergy supply was 9,733 megawatts. Most biofuels are co-combusted with coal to achieve baseload power (the energy needed to meet increased demand during peak loads). Bioenergy provides more than 3% of total US energy consumption. In the US, biofuels have surpassed hydroelectric power as a renewable energy source.
Very often, biofuel is used by the industry that creates it. For example, the wood processing industry burns its own wood waste to produce the steam and electricity needed to run the factory. Waste includes sawdust, unused branches and wood chips. The forestry industry obtains more than 50% of its electricity needs from its own waste. The same goes for the paper industry.
Another option for using biomass is to produce biofuels. Starch or sugar-containing cereals are converted into ethyl alcohol: ethanol. In Brazil, most transport is fueled by ethanol. The transition to ethanol began in the mid-1970s when gasoline prices first increased. Brazilian industry leaders have decided to reduce the country's dependence on oil. The ethanol industry has grown slowly, year after year. In Brazil, sugar cane is grown and fermented into ethanol. Brazilian cars must be universal, that is, run on both ethanol and gasoline. Consumers made their own choices based on the price of fuel.
Soon other countries began to adopt Brazil's experience. Ethanol production is increasing in China and the European Union. The United States produced 12.9 billion liters of ethanol in 2004, almost double the 2002 figure. The ethanol produced is added to gasoline to increase octane and reduce emissions. In the US, the source of ethanol is corn. Cereals produce less ethanol than sugar cane or beets; the yield of ethanol on land is half as much.
An alternative to corn as a source of ethanol in the United States may be switchgrass. Native to North America, millet is a more efficient source of ethanol than corn. The use of this cereal is under trial.
In the United States, a mixture of gasoline and ethanol called E-diesel is being used experimentally to fuel city buses. As gasoline prices rise, ethanol fuel consumption continues to increase for ethanol fueled vehicles.
Biodiesel consumption is also growing in Europe. Biodiesel fuel is obtained from vegetable oil that has undergone so-called transesterification. Animal fat and restaurant waste can also be turned into biofuel. In the coming days, this biofuel can completely replace diesel fuel or be used as a mixture: 20% biofuel and 80% diesel. In 2005, European countries produced more than 3 million metric tons of biofuel. The largest consumer and producer is Germany. Special programs to popularize the use of biofuels are beginning to appear around the world.
Obstacles
There are barriers to using biomass as a fuel. As with fossil fuels, combustion produces CO 2 . However, fossil fuels emit CO 2 for millions of years, creating excess CO 2 in the atmosphere. In contrast, CO 2 released by biomass during combustion is absorbed by plants. Biofuels are considered "carbon neutral".
In the biological equation, fossil fuels still play a key role. They are used at all stages of biomass production: plant growing, harvesting, delivery and processing. Biomass will not become carbon neutral until all stages use renewable fuels. When this will happen is a mystery to everyone. So far, biofuels can reduce CO 2 emissions, since in the process of using biomass less CO 2 is emitted into the atmosphere.
With the flow
In the future, biomass may replace oil, gas and coal in many areas. Governments of various countries will fund research into the development of biofuels. Among the things to be improved are biomass refineries. Such factories will accept various types of biofuels and create a constant supply for use in various industries. One refinery uses sugar in the form of cellulose and lignin from plants as the basis for fermentation, resulting in ethanol. Wood and various types of grasses can be used as biofuel. Other refineries use a thermochemical approach to standardize biomass, converting the mass into a more efficient liquid or gas.
Researchers see the future of biomass as replacing petroleum as the source of many chemicals used in the modern world. Plastic items, paints and adhesives can be produced not from petroleum products, but from biomass.
A power plant that converts the Earth's internal heat into electrical energy. See also: Power plants Financial Dictionary Finam... Financial Dictionary
A thermal power plant that converts the internal heat of the Earth (the energy of hot steam-water sources) into electrical energy. In Russia, the first geothermal power plant (Pauzhetskaya) with a capacity of 5 MW was launched in 1966 in Kamchatka; by 1980 its power... ... Big Encyclopedic Dictionary
geothermal power plant- geothermal power plant A power plant designed to convert the deep heat of the Earth into electrical energy. [GOST 26691 85] EN geothermal power station a thermal power station in which thermal energy is extracted from suitable parts of the… … Technical Translator's Guide
geothermal power plant- A power plant that converts the internal heat of the Earth (the energy of hot steam-water sources) into electrical energy... Dictionary of Geography
Thermal power plant that converts the internal heat of the Earth (the energy of hot steam-water sources) into electrical energy. In Russia, the first geothermal power plant with a capacity of 5 MW was launched in 1966 (in Kamchatka, in the valley of the Pauzhetka River); by 1980 its capacity was increased... ... encyclopedic Dictionary
A thermal power plant that uses the Earth's internal heat to generate electricity and heat. Almost the only sources of geothermal energy are steam hydrotherms (deposits of self-flowing steam-air mixture... ... Encyclopedia of technology
Geothermal power plant- STES 32. Geothermal power plant A power plant designed to convert the deep heat of the Earth into electrical energy Source: GOST 26691 85: Thermal power engineering. Terms and definitions original document... Dictionary-reference book of terms of normative and technical documentation
Thermal power plant that uses the thermal energy of the Earth's thermal waters to generate electricity and heat supply. The complex of structures includes: boreholes that bring a steam-water mixture or steam to the surface; gas and... ... Geographical encyclopedia
geothermal power plant- geoterminė elektrinė statusas T sritis Energetika apibrėžtis Elektrinė, kurioje žemės gelmių šiluma verčiama elektros energija. atitikmenys: engl. geothermal power station vok. Erdwärmekraftwerk, n; geothermisches Kraftwerk, n rus. geothermal... ... Aiškinamasis šiluminės ir branduolinės technikos terminų žodynas
A thermal power plant that uses the thermal energy of the Earth's hot springs to generate electricity and heat supply. The temperature pa of geothermal waters can reach 200 °C or more. In G. e. includes: boreholes leading to the surface... ... Big Encyclopedic Polytechnic Dictionary
Kirill Degtyarev, researcher, Moscow State University. 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 at the beginning of the 19th century 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. A heat pump system, or heat multiplier as Thompson called it, is based on the physical process of transferring heat from the environment to a 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 removed heat into the 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 through the evaporator enters the internal environment - the 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, but the transformation ratio (the ratio of energy consumed to energy produced) in modern systems is high enough to ensure their efficiency.
Currently, heat pumps are quite widely used for space heating, mainly in economically developed countries.
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 GeoPPs, 1042 g at coal-fired thermal power plants, 906 g at oil-fired power plants and 453 g at gas-fired 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, at the 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 the costs of constructing a nuclear power plant and is comparable to the costs of constructing 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 power. 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. Thus, chemical elements and compounds extracted from thermal water can provide additional income. Let us recall the example of Larderello: chemical production was primary there, 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, it depends to a much greater extent 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 G.).
In addition, geothermal energy is less technologically intensive compared to wind and, especially, solar energy: geothermal station systems are quite simple.
In the overall structure of world electricity production, the geothermal component accounts for less than 1%, 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 have become pioneers and centers for the development of geothermal energy in Russia - Kamchatka and the North Caucasus, and if in the first case we are talking primarily about the electric power industry, then in the second - about the use of thermal energy from thermal water.
In the North Caucasus - in the Krasnodar Territory, 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 at domestic power engineering enterprises.
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, the Kuril Islands - the Russian part of 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 centralized energy supplies.
Probably, in the coming decades, geothermal energy in our country will develop precisely in such regions.
Geothermal power plants are the way to a brighter future, where fuel will no longer drive the economies of countries. Today, many useful schemes have been developed that make it possible to completely abandon other sources. It even actively uses the latest technologies, so you shouldn’t be surprised by new design developments.
The operating principle of a geothermal power plant is related to the peculiarities of the earth's crust. The world stores colossal heat, the use of which provides almost unlimited possibilities. People have been thinking about them for centuries, but only now have developments completed that have revealed numerous secrets. What principle continues to guide the work?
The operation of geothermal power plants is based on the use of heat from the earth. For this reason, specialists are working on complex schemes that are partially different from each other. It is worth clarifying their features to show how they managed to curb nature.
The basis of the direct operating principle of GeoTES is the passage of hot steam through pipes through turbines. As a result, considerable energy is released, which is immediately transferred to electric generators. It turns out that water heated by the earth's crust transmits temperature. Although such a concept should be considered exaggerated.
Indirect
Geothermal power plants in Russia operate on different principles. The most widespread is the indirect principle, when gases that can destroy pipes are removed from the water after treatment. In Kamchatka, a similar principle is used, when the land provides irreplaceable support.
Mixed
The mixed principle of operation is a little more complicated. A thermal power plant can be an excellent source of electricity for an entire area. It lies in the fact that water also passes through the pipes, but after condensation, absolutely all undissolved gases are removed. As a result, the use of a thermal power plant becomes completely environmentally friendly.
Binary
The binary principle dictates that thermal power plants can be built anywhere. The region has a greater influence on the operation, since the heat exchanger acts as the basis. This liquid has a low boiling point, so water easily turns it into steam. Such a heat source makes it possible to significantly increase power, as well as ensure stability.
Geothermal power plants in Russia
Some people believe that solar energy is the future, but this is a mistake. The geothermal type provides more opportunities, so it is more profitable to immediately build a permanent facility than to risk interruptions in the future.
The main disadvantage of geothermal power plants is that they are tied to a specific location. There should be geysers around it, eliminating complex work. Gradually, designers are solving this problem, but for now power plants continue to operate according to outdated principles.
Geothermal power plants hide their shortcomings, which is directly related to the long life of hot springs. Although environmentalists attract public attention to other details. Thus, the main disadvantage and principle of operation of power plants in Russia is their location, while in other countries they note the high cost of construction.
When wondering in which region geothermal power plants are built, people should understand that most of them are located in Kamchatka. New regions are planned to appear in the future, but so far there is no need for this, which leaves alternative energy sources in the background due to traditional fuel.
Introduction
1. Geothermal energy
Conclusion
Bibliography
Introduction
The power supply of a society is the basis of its 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. The developing world economy requires a constant increase in the energy 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 directly using heat is widespread at tectonic plate boundaries, for example in Iceland, Japan, and the 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 Guinea5 6Guatemala53 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. 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) 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 us to move on to the large-scale implementation of 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. Therefore, special attention is paid 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 future production of 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, it will not exceed 0.2% with a total output of 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. The development of geothermal energy in Kamchatka is currently 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, the production capacity of the Mutnovskaya Geothermal Power Plant will increase 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 we use steam turbines with close to atmospheric back pressure and direct the exhaust steam to a condenser, which is also a steam generator of 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 efficiency cannot be fully realized due to high air temperatures. 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 public networks; 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. 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. 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. 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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