Advantages and disadvantages of geothermal energy. Geothermal energy - power plants on a volcano Geothermal power plants, their advantages and disadvantages

This energy belongs to alternative sources. Nowadays, they increasingly mention the possibilities of obtaining the resources that the planet gives us. We can say that we live in an era of fashion for renewable energy. Many technical solutions, plans, and theories are being created in this area.

It is located deep in the depths of the earth and has the properties of renewal, in other words, it is endless. Classic resources, according to scientists, are beginning to run out, oil, coal, and gas will dry up.

Nesjavellir Geothermal Power Plant, Iceland

Therefore, we can gradually prepare to adopt new alternative methods of energy production. Under the earth's crust there is a powerful core. Its temperature ranges from 3000 to 6000 degrees. The movement of lithospheric plates demonstrates its enormous power. It manifests itself in the form of a volcanic outburst of magma. Radioactive decay occurs in the depths, sometimes prompting such natural disasters.

Typically, magma heats the surface without going beyond it. This creates geysers or warm pools of water. Thus, it is possible to use physical processes in for the right purposes for humanity.

Types of geothermal energy sources

It is usually divided into two types: hydrothermal and petrothermal energy. The first is formed due to warm sources, and the second type is the difference in temperatures on the surface and deep in the earth. Explaining in your own words, a hydrothermal vent consists of steam and hot water, and petrothermal is hidden deep under the ground.

Map of geothermal energy development potential in the world

For petrothermal energy, it is necessary to drill two wells, fill one with water, after which a steaming process will occur, which will come to the surface. There are three classes of geothermal areas:

• Geothermal – located near continental plates. Temperature gradient more than 80C/km. As an example, the Italian commune of Larderello. There is a power plant there
• Semi-thermal – temperature 40 – 80 C/km. These are natural aquifers consisting of fragmented rocks. In some places in France, buildings are heated this way.
• Normal – gradient less than 40 C/km. The representation of such areas is most common

They are excellent source for consumption. They are located in the rock at a certain depth. Let's look at the classification in more detail:

• Epithermal - temperature from 50 to 90 C
• Mesothermal – 100 – 120 s
• Hypothermal – more than 200 s

These types consist of different chemical composition. Depending on it, water can be used for various purposes. For example, in the production of electricity, heat supply (heat routes), raw material base.

Video: Geothermal Energy

Heating process

The water temperature is 50 -60 degrees, which is optimal for heating and hot supply of residential areas. The need for heating systems depends on the geographical location and climatic conditions. And people constantly need hot water supply. For this process, GTS (geothermal thermal stations) are constructed.

If for the classic production of thermal energy a boiler house is used that consumes solid or gas fuel, then in this production a geyser source is used. The technical process is very simple, the same communications, thermal routes and equipment. It is enough to drill a well, clean it of gases, then send it with pumps to the boiler room, where the temperature schedule will be maintained, and then it will enter the heating main.

The main difference is that there is no need to use a fuel boiler. This significantly reduces the cost of thermal energy. In winter, subscribers receive heat and hot water supply, and in summer only hot water supply.

Power generation

Hot springs and geysers serve as the main components in the production of electricity. For this purpose, several schemes are used, and special power plants are built. GTS device:

• DHW tank
• Pump
• Gas separator
• Steam separator
• Generating turbine
• Capacitor
• Boost pump
• Tank-cooler

As we can see, the main element of the circuit is the steam converter. This allows you to obtain purified steam, since it contains acids that destroy turbine equipment. It is possible to use a mixed scheme in the technological cycle, that is, water and steam are involved in the process. The liquid goes through the entire stage of purification from gases, just like steam.

Binary source circuit

The working component is a liquid with a low boiling point. Thermal water is also involved in the production of electricity and serves as a secondary raw material.

With its help, steam from a low-boiling source is formed. GTS with such an operating cycle can be fully automated and do not require maintenance personnel. More powerful stations use a dual-circuit circuit. This type of power plant allows reaching a capacity of 10 MW. Double circuit structure:

• Steam generator
• Turbine
• Capacitor
• Ejector
• Feed pump
• Economizer
• Evaporator

Practical use

The huge reserves of the sources are many times greater than the annual energy consumption. But only a small fraction is used by humanity. The construction of the stations dates back to 1916. The first geothermal power plant with a capacity of 7.5 MW was created in Italy. The industry is actively developing in countries such as the USA, Iceland, Japan, the Philippines, and Italy.

Active exploration of potential locations and more convenient extraction methods are underway. Production capacity is growing from year to year. If we take into account the economic indicator, then the cost of such an industry is equal to coal-fired thermal power plants. Iceland almost completely covers its housing stock with a GT source. 80% of houses use hot water from wells for heating. Experts from the USA claim that with proper development, geothermal power plants can produce 30 times more annual consumption. If we talk about potential, 39 countries of the world will be able to fully provide themselves with electricity if they use 100 percent of the earth’s subsoil.

Located at a depth of 4 km:

Japan is located in a unique geographic area associated with the movement of magma. Earthquakes and volcanic eruptions occur constantly. With such natural processes, the government is introducing various developments. 21 facilities have been created with a total capacity of 540 MW. Experiments are being conducted to extract heat from volcanoes.

Pros and cons of GE

As mentioned earlier, GE is used in various fields. There are certain advantages and disadvantages. Let's talk about the advantages:

• Infinity of resources
• Independence from weather, climate and time
• Versatility of application
• Environmentally friendly
• Low cost
• Provides energy independence to the state
• Compact station equipment

The first factor is the most basic, it encourages us to study such an industry, since an alternative to oil is quite relevant. Negative changes in the oil market are aggravating the global economic crisis. During operation of the installations, the external environment is not polluted, unlike others. And the cycle itself does not require dependence on resources and its transportation to the gas transportation system. The complex provides for itself and does not depend on others. This is a huge plus for countries with low levels of mineral resources. Of course, there are negative aspects, let’s take a look at them:

• High cost of development and construction of stations
• The chemical composition requires disposal. It needs to be poured back into the depths or ocean
• Hydrogen sulfide emissions

Emissions of harmful gases are very insignificant and are not comparable with other industries. The equipment allows you to effectively remove it. Waste is dumped into the ground, where wells are equipped with special cement frames. This technique eliminates the possibility of groundwater contamination. Expensive developments tend to decrease as their improvements progress. All shortcomings are carefully studied, and work is underway to eliminate them.

Further potential

The accumulated basis of knowledge and practice becomes the foundation for future achievements. It is too early to talk about complete replacement of traditional reserves, since thermal zones and methods of extracting energy resources have not been fully studied. For faster development, more attention and financial investments are required.

While society is becoming familiar with the possibilities, it is slowly moving forward. According to expert estimates, only 1% of the world's electricity is produced by this fund. It is possible that comprehensive programs for the development of the industry at the global level will be developed, mechanisms and means of achieving goals will be worked out. The energy of the subsoil can solve environmental problem, because every year there are more harmful emissions into the atmosphere, the oceans are polluted, and the ozone layer becomes thinner. For the rapid and dynamic development of the industry, it is necessary to remove the main obstacles, then in many countries it will become a strategic springboard, capable of dictating conditions in the market and raising the level of competitiveness.

The Earth has long been a source of energy resources, but, recognizing this fact, we must also admit that non-renewable energy sources are not infinite. For the sake of heating their homes, people have already abandoned firewood and no longer burn forests; they have almost eliminated coal mining, recognizing that this causes environmental damage to the environment. But oil and gas production is in full swing. Meanwhile, our planet also has a renewable source of energy - the power of its geothermal waters.

Warmth from the very depths of the planet

Using the Earth's heat is a very tempting idea and a difficult, but generally solvable, task. This is especially true for regions where geothermal sources come to the surface or are at least within reach, both from an engineering and economic point of view. But the location of such sources, as a rule, is adjacent to tectonic faults of the planet and is located in extremely seismically unstable regions.

Geothermal power plants: advantages and disadvantages

There are several circuit diagrams construction of such power plants and, usually, the choice depends on the specific heat source: somewhere it is enough to drill a well and you can begin its operation, but somewhere it is first necessary to clean the incoming energy carrier from solid particles and harmful gases.

But, whatever the operating principle of such a station, it has a number of advantages over thermal power plants and even over thermal nuclear power plants.

Here's the drawback geothermal station just one: ultimately it comes down to its location. Considering that seismic activity cannot be predicted, areas of tectonic faults are an extremely unfavorable place for the construction and subsequent operation of power plants.

But the advantages are numerous and undeniable:

• safety for environment, including the absence of greenhouse gases;
• compact size of the station;
• the main costs end with the completion of construction, while operating costs are minimal;
• Due to the natural coolant (a practically inexhaustible resource!), the cost of electrical energy is reduced to almost zero.

More about ecology

With the development of society, its environmental awareness also grows, and problems of reasonable environmental management come to the fore. Leading economic powers, including Russia, are signing protocols to limit atmospheric emissions in an effort to reduce the harm from the greenhouse effect and prevent global warming. Thermal power plants that use gas, petroleum products and, especially, coal as fuel to generate electricity have a significant impact on the growth of air pollution.

Nothing can be done about the fact that there is an environmental drawback of thermal power plants. You can try to reduce emissions through more complete combustion of fuel, through the use of advanced filter systems, but you cannot escape the “generic” disadvantage of thermal energy.

Therefore, the main question that arises in connection with the use of thermal energy is what environmental benefits does a geothermal power plant have? Using water and steam heated by nature, these power plants produce no emissions. Minimizes the harm caused to the environment and the small dimensions of such stations. So, the advantages of geothermal power plants over thermal power plants are beyond doubt.

Geothermal power plants(GeoPP) is a type of alternative energy. GeoPPs receive electrical energy from geothermal sources in the Earth's interior - geysers, open and underground hot springs of water or methane, warm dry rocks, magma. Since geological activity occurs regularly on the planet, geothermal sources can be conditionally considered inexhaustible (renewable). According to scientists' calculations thermal energy The Earth has 42 trillion watts, 2% of which (840 billion) are contained in the earth's crust and are available for mining, but this figure is enough to provide the Earth's population with inexhaustible energy for many years.

Regions with geothermal activity exist in many parts of the planet, and areas with high geological activity (volcanic, seismic) are considered ideal for constructing stations. The most active development of the industry occurs in places where hot geysers accumulate, as well as in areas around the edges of lithospheric plates due to the smallest thickness of the earth’s crust.

To obtain heat from closed underground sources, well drilling is used. When a well is deepened, the temperature rises by about 1 degree every 36 meters, but there are higher rates. The resulting heat is delivered to the surface of the station in the form of hot water or steam; they can be used for direct supply to heating systems houses and premises, and for subsequent conversion into electricity at the station.

Depending on the state of the medium (water, steam), three methods of generating electricity are used - direct, indirect and mixed. When direct, dry steam is used, acting directly on the generator turbine. Indirectly, purified and heated water vapor is used (the most popular at present), obtained by evaporating water pumped from underground sources at temperatures up to 190 degrees. As can be seen from the presented figure, superheated steam rises through production wells to the heat exchanger. It transfers thermal energy into the closed circuit of the steam turbine. The steam obtained from boiling the liquid rotates the turbine, after which it condenses again in the heat exchanger, which forms a closed system that is practically harmless to the atmosphere. The steam turbine is connected to an electric generator, from which electricity is obtained. In the mixed method, intermediate, easily boiling liquids (freon, etc.) are used, which are exposed to boiling water from sources.

Advantages of geothermal power plants:

1) The stations do not require external fuel to operate;

2) Virtually inexhaustible reserves of energy (if you follow the necessary conditions);

3) Possibility of automated and autonomous operation through the use of self-generated electricity;

4) Relative cheapness of station maintenance;

5) Stations can be used for desalination of water when located on the ocean or sea coast.

Geothermal power plants - disadvantages:

1) The choice of location for the station is often complicated by political and social aspects;

2) Design and construction of GeoPP may require very large investments;

3) Atmospheric pollution by periodic emissions through a well of harmful substances contained in the bark ( modern technologies allow some of these emissions to be converted into fuel), but it is significantly lower than when producing electricity from fossil sources;

4) Instability of natural geological processes and, as a consequence, periodic shutdown of stations.

First geothermal power plant

The first experiments with energy extraction from geothermal sources date back to the beginning of the 20th century (1904, Italy, where a short time later the first full-fledged geothermal power plant was also built). Currently, taking into account the rapid growth in electricity consumption and the rapid depletion of reserves of traditional energy raw materials, this is one of the most promising energy sectors.

Largest geothermal power plants

The leaders in geothermal energy production are now the USA and the Philippines, where the largest geothermal power plants have been built, producing more than 300 MW of energy each, which is enough to power large cities.

Geothermal power plants in Russia

In Russia, the industry is less developed, but active development is underway here too. The most promising regions of the country are the Kuril Islands and Kamchatka. The country's largest geothermal power plant is the Mutnovskaya GeoPP in the southeast of Kamchatka, producing up to 50 MW of energy (in the future - up to 80 MW). Also noteworthy are the Pauzhetskaya (the first built in Russia), Okeanskaya and Mendeleevskaya GeoPPs.

The current demand for geothermal energy as one of the types of renewable energy is due 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 fuel and nuclear power on the human environment and 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 make a significant contribution to 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 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.

· 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 heating, 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 increasing low temperatures. 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 table 1 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 various technological processes it is possible to achieve the most complete realization of the 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 an underground aquifer. Another disadvantage of this energy is the high mineralization of thermal waters of 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 water systems located on the surface. The disadvantages of geothermal energy noted above lead to the fact that for practical use The heat of geothermal water requires significant capital expenditures for drilling wells, reinjection of waste geothermal water, as well as for the creation of corrosion-resistant heating 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 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°C, which allows for a much wider use of geothermal power plants for generating electricity. In connection with this, 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 source energy potential

Geothermal power plants in Russia are a promising renewable source. Russia has rich geothermal resources with high and low temperatures and is making good steps in this direction. The concept of environmental protection can help demonstrate the benefits of renewable energy alternatives.

In Russia, geothermal research was carried out in 53 scientific centers and higher educational institutions located in different cities and in different departments: the Academy of Sciences, Ministries of Education, natural resources, fuel and energy. Such work is carried out in some regional scientific centers, such as Moscow, St. Petersburg, Arkhangelsk, Makhachkala, Gelendzhik, the Volga region (Yaroslavl, Kazan, Samara), the Urals (Ufa, Yekaterinburg, Perm, Orenburg), Siberia (Novosibirsk, Tyumen, Tomsk, Irkutsk, Yakutsk), Far East (Khabarovsk, Vladivostok, Yuzhno-Sakhalinsk, Petropavlovsk-on-Kamchatka).

In these centers, theoretical, applied, regional research is carried out, and special tools are created.

Use of Geothermal Energy

Geothermal power plants in Russia are used mainly for heat supply and heating of several cities and settlements in the North Caucasus and Kamchatka with a total population of 500 thousand people. In addition, in some regions of the country deep heat is used for greenhouses with total area 465 thousand m2. The most active hydrothermal resources are used in Krasnodar region, Dagestan and Kamchatka. Approximately half of the extracted resources is used to supply heat to housing and industrial premises, a third is used to heat greenhouses, and only about 13% is used for industrial processes.

In addition, thermal waters are used in approximately 150 sanatoriums and 40 bottling plants mineral water. The amount of electrical energy developed by geothermal power plants in Russia is increasing compared to the world, but remains extremely insignificant.

The share is only 0.01 percent of the country's total electricity generation.

Most promising direction The use of low-temperature geothermal resources is the use of heat pumps. This method is optimal for many regions of Russia - in the European part of Russia and in the Urals. So far, the first steps in this direction are being taken.

Electricity is generated at some power plants (GeoPP) only in Kamchatka and Kuril Islands. Currently, three stations operate in Kamchatka:

Pauzhetskaya GeoPP (12 MW), Verkhne-Mutnovskaya (12 MW) and Mutnovskaya GeoPP (50 MW).

Pauzhetskaya GeoPP inside

Two small geothermal power plants are in operation on the islands of Kunashir - Mendeleevskaya Geothermal Power Plant, Iturup - "Okeanskaya" with an installed capacity of 7.4 MW and 2.6 MW, respectively.

Geothermal power plants in Russia rank last in the world in terms of their volume.In Icelandaccounts for more than 25% of the electricity produced by this method.

Mendeleevskaya Geothermal Power Plant in Kunashir

Iturup – “Ocean”

Russia has significant geothermal resources and the existing potential is much greater than the current situation.

This resource is far from adequately developed in the country. In the former Soviet Union, geological exploration for minerals, oil and gas was well supported. However, such extensive activity is not aimed at studying geothermal reservoirs, even as a consequence of the approach: geothermal waters were not considered energy resources. But still, the results of drilling thousands of “dry wells” (colloquial in the oil industry) bring secondary benefits for geothermal research. These abandoned wells, which were used during oil industry research, are cheaper to repurpose for new purposes.

Advantages and challenges of using geothermal resources

The environmental benefits of using renewable energy sources such as geothermal are recognized. However, there are significant barriers to the development of renewable resources that hinder development. Detailed geological surveys and expensive drilling of geothermal wells represent a major financial outlay associated with significant geological and technical risks.

There are also benefits to using renewable energy sources, including geothermal resources.

• First, the use of local energy resources can reduce dependence on imports or the need to build new generating capacity for heating in industrial or residential hot water supply areas.
• Second, replacing traditional fuels with clean energy produces significant environmental and public health improvements and associated savings.
• Third, the measure of energy savings is related to efficiency. District heating systems are common in Russian urban centers and need to be modernized and switched to renewable energy sources with their own advantages. This is especially important from an economic point of view; outdated district heating systems are not economical and their engineering life has already expired.

Geothermal power plants in Russia are “cleaner” compared to those using fossil fuels. The International Convention on Climate Change and European Community programs provide for the promotion of renewable energy sources. However, specific legal regulations regarding geothermal exploration and production are lacking in all countries. This is partly because waters are regulated under water laws, minerals under energy laws.

Geothermal energy does not belong to certain sections of legislation and it is difficult to decide on different methods of exploitation and use of geothermal power.

Geothermal Energy and Sustainable Development

Industrial development over the past two centuries has brought many innovations to human civilization and brought the exploitation of natural resources at an alarming rate. Since the seventies of the 20th century, serious warnings about the “limits to growth” have gone around the world with great effect: resource exploitation, the arms race, and wasteful consumption have squandered these resources at an accelerated pace, along with the exponential growth of the planet's population. All this madness requires more energy.

The most wasteful and unpromising is human irresponsibility in the habit of using up finite and rapidly depleting energy resources of coal, oil and gas. These irresponsible activities are carried out by the chemical industry to produce plastics, synthetic fibers, building materials, paints, varnishes, pharmaceutical and cosmetic products, pesticides and many other organic chemical products.

But the most catastrophic effect of the use of fossil fuels is the balance of the biosphere and climate to such an extent that it will irreversibly affect our life choices: the growth of deserts, acid rain spoiling fertile lands, poisoning of rivers, lakes and groundwater, spoilage drinking water for the world's growing population - and the worst of all - more frequent weather disasters, drawing in glaciers, destroying ski resorts, melting glaciers, landslides, more severe storms, flooding of densely populated coastal areas and islands, thereby endangering people and rare species of flora and fauna as a result of migrations.

Loss of fertile lands and cultural heritage occurs due to the extraction of inexorably growing fossil fuels, emissions into the atmosphere that cause global warming.

The path to clean, sustainable energy that preserves resources and brings the biosphere and climate into the natural balance is associated with the use of geothermal power plants in Russia.

Scientists understand the need to reduce the burning of fossil fuels beyond the Kyoto Protocol targets in order to slow global warming of the Earth's atmosphere.