The warmth of the earth. Likely sources internal heat

Geothermy- science that studies the thermal field of the Earth. The average temperature of the earth's surface is general trend to a decrease. Three billion years ago, the average temperature on the Earth's surface was 71 o, now it is 17 o. Sources of heat (thermal ) Earth's fields are internal and external processes. The heat of the Earth is caused by solar radiation and originates in the bowels of the planet. The values ​​of heat influx from both sources are quantitatively extremely different and their roles in the life of the planet are different. Solar heating of the Earth is 99.5% of the total amount of heat received by its surface, and internal heating accounts for 0.5%. In addition, the influx of internal heat is very unevenly distributed on the Earth and is concentrated mainly in places of manifestation of volcanism.

External source is solar radiation . Half of the solar energy is absorbed by the surface, vegetation and subsurface layer earth's crust. The other half is reflected into world space. Solar radiation maintains the temperature of the Earth's surface at an average of about 0 0 C. The sun warms the near-surface layer of the Earth to an average depth of 8 - 30 m, with an average depth of 25 m, the effect of solar heat ceases and the temperature becomes constant (neutral layer). This depth is minimal in areas with a maritime climate and maximal in the Subpolar region. Below this boundary there is a belt of constant temperature corresponding to the average annual temperature of the area. So, for example, in Moscow on the territory of agricultural. academy. Timiryazev, at a depth of 20 m, the temperature has invariably remained equal to 4.2 o C since 1882. In Paris, at a depth of 28 m, the thermometer has consistently shown 11.83 o C for more than 100 years. The layer with a constant temperature is the deepest where perennial ( permafrost. Below the belt of constant temperature is the geothermal zone, which is characterized by heat generated by the Earth itself.

Internal sources are the bowels of the Earth. The Earth radiates more heat into space than it receives from the Sun. Internal sources include residual heat from the time the planet was melted, heat thermonuclear reactions flowing in the bowels of the Earth, the heat of gravitational compression of the Earth under the action of gravity, the heat of chemical reactions and crystallization processes, etc. (eg tidal friction). The heat from the bowels comes mainly from the moving zones. The increase in temperature with depth is associated with the existence internal sources heat - decay radioactive isotopes– U, Th, K, gravitational differentiation of matter, tidal friction, exothermic redox chemical reactions, metamorphism and phase transitions. The rate of temperature increase with depth is determined by a number of factors - thermal conductivity, permeability of rocks, proximity to volcanic chambers, etc.

Below the belt of constant temperatures there is an increase in temperature, on average 1 o per 33 m ( geothermal stage) or 3 o every 100 m ( geothermal gradient). These values ​​are indicators of the thermal field of the Earth. It is clear that these values ​​are average and vary in value in various areas or areas of the earth. Geothermal stage in various points The earth is different. For example, in Moscow - 38.4 m, in Leningrad 19.6, in Arkhangelsk - 10. So, when drilling a deep well on the Kola Peninsula at a depth of 12 km, a temperature of 150 ° was assumed, in reality it turned out to be about 220 degrees. When drilling wells in the northern Caspian at a depth of 3000 m, the temperature was assumed to be 150 degrees, but it turned out to be 108 degrees.

It should be noted that the climatic features of the area and the average annual temperature do not affect the change in the value of the geothermal step, the reasons lie in the following:

1) in the different thermal conductivity of the rocks that make up a particular area. Under the measure of thermal conductivity is understood the amount of heat in calories transferred in 1 second. Through a section of 1 cm 2 with a temperature gradient of 1 o C;

2) in the radioactivity of rocks, the greater the thermal conductivity and radioactivity, the lower the geothermal step;

3) in various conditions occurrence of rocks and age of disturbance of their occurrence; observations have shown that the temperature rises faster in the layers collected in folds, they often have violations (cracks), through which the access of heat from the depths is facilitated;

4) the nature of groundwater: hot groundwater flows warm rocks, cold ones cool;

5) remoteness from the ocean: near the ocean due to the cooling of rocks by a mass of water, the geothermal step is larger, and at the contact it is smaller.

Knowing the specific value of the geothermal step is of great practical importance.

1. This is important when designing mines. In some cases, it will be necessary to take measures to artificially lower the temperature in deep workings (temperature - 50 ° C is the limit for a person in dry air and 40 ° C in wet air); in others, it will be possible to work at great depths.

2. Great importance has an assessment of temperature conditions during tunneling in mountainous areas.

3. The study of the geothermal conditions of the Earth's interior makes it possible to use steam and hot springs emerging on the Earth's surface. Underground heat is used, for example, in Italy, Iceland; in Russia, an experimental industrial power plant was built on natural heat in Kamchatka.

Using data on the size of the geothermal step, we can make some assumptions about temperature conditions deep zones of the earth. If we take the average value of the geothermal step as 33 m and assume that the increase in temperature with depth occurs evenly, then at a depth of 100 km there will be a temperature of 3000 ° C. This temperature exceeds the melting points of all substances known on Earth, therefore, at this depth there should be molten masses . But due to the huge pressure of 31,000 atm. Superheated masses do not have the characteristics of liquids, but are endowed with the characteristics of a solid body.

With depth, the geothermal step must apparently increase significantly. If we assume that the step does not change with depth, then the temperature in the center of the Earth should be about 200,000 degrees, and according to calculations, it cannot exceed 5000 - 10,000 degrees.

With the development and formation of society, mankind began to look for more and more modern and at the same time economical ways to obtain energy. For this, various stations are being built today, but at the same time, the energy contained in the bowels of the earth is widely used. What is she like? Let's try to figure it out.

geothermal energy

Already from the name it is clear that it represents the heat of the earth's interior. Under the earth's crust is a layer of magma, which is a fiery-liquid silicate melt. According to research data, energy potential of this heat is much higher than the energy of world reserves natural gas, as well as oil. Magma comes to the surface - lava. Moreover, the greatest activity is observed in those layers of the earth on which the boundaries of tectonic plates are located, as well as where the earth's crust is characterized by thinness. The geothermal energy of the earth is obtained as follows: the lava and water resources of the planet are in contact, as a result of which the water begins to heat up sharply. This leads to the eruption of the geyser, the formation of the so-called hot lakes and undercurrents. That is, precisely those phenomena of nature, the properties of which are actively used as energies.

Artificial geothermal sources

The energy contained in the bowels of the earth must be used wisely. For example, there is an idea to create underground boilers. To do this, you need to drill two wells of sufficient depth, which will be connected at the bottom. That is, it turns out that in almost any corner of the land you can get geothermal energy. industrial way: cold water will be pumped into the reservoir through one well, and extracted through the second hot water or steam. Artificial heat sources will be beneficial and rational if the resulting heat will provide more energy. The steam can be sent to turbine generators that will generate electricity.

Of course, the extracted heat is only a fraction of what is available in the total reserves. But it should be remembered that the deep heat will be constantly replenished due to the processes of compression of rocks, stratification of the bowels. According to experts, the earth's crust accumulates heat, the total amount of which is 5,000 times greater calorific value all the fossil resources of the earth as a whole. It turns out that the operating time of such artificially created geothermal stations can be unlimited.

Source Features

The sources that make it possible to obtain geothermal energy are almost impossible to fully use. They exist in more than 60 countries of the world, with the largest number of terrestrial volcanoes on the territory of the Pacific volcanic ring of fire. But in practice, it turns out that geothermal sources in different regions worlds are completely different in their properties, namely, average temperature, salinity, gas composition, acidity, and so on.

Geysers are sources of energy on Earth, the peculiarities of which are that they spew boiling water at certain intervals. After the eruption, the pool becomes free of water, at its bottom you can see a channel that goes deep into the ground. Geysers as energy sources are used in regions such as Kamchatka, Iceland, New Zealand and North America, and single geysers are also found in some other areas.

Where does energy come from?

Uncooled magma is located very close to the earth's surface. Gases and vapors are released from it, which rise and pass through the cracks. Mixing with groundwater, they cause them to heat up, they themselves turn into hot water, in which many substances are dissolved. This water is released to the earth's surface in the form of geothermal sources: hot keys, mineral springs, geysers and so on. According to scientists, the hot bowels of the earth are caves or chambers connected by passages, cracks and channels. They are just filled with groundwater, and very close to them are magma chambers. In this natural way, the thermal energy of the earth is formed.

Earth's electric field

There is another alternative energy source in nature, which is renewable, environmentally friendly, and easy to use. True, so far this source has only been studied and not applied in practice. So, the potential energy of the Earth lies in its electric field. It is possible to obtain energy in this way based on the study of the basic laws of electrostatics and the features of the Earth's electric field. In fact, our planet from an electrical point of view is a spherical capacitor charged up to 300,000 volts. Its inner sphere has a negative charge, and the outer one - the ionosphere - is positive. is an insulator. Through it there is a constant flow of ionic and convective currents, which reach strengths of many thousands of amperes. However, the potential difference between the plates does not decrease in this case.

This suggests that in nature there is a generator, the role of which is to constantly replenish the leakage of charges from the capacitor plates. The role of such a generator is played by the Earth's magnetic field, which rotates together with our planet in the flow of the solar wind. The energy of the Earth's magnetic field can be obtained just by connecting an energy consumer to this generator. To do this, you need to install a reliable ground.

Renewable sources

As the population of our planet is steadily growing, we need more and more energy to provide for the population. The energy contained in the bowels of the earth can be very different. For example, there are renewable sources: wind, solar and water energy. They are environmentally friendly, and therefore you can use them without fear of harming the environment.

water energy

This method has been used for many centuries. Built today great amount dams, reservoirs, in which water is used to generate electrical energy. The essence of this mechanism is simple: under the influence of the flow of the river, the wheels of the turbines rotate, respectively, the energy of the water is converted into electrical energy.

Today there is a large number of hydroelectric power plants that convert the energy of the flow of water into electricity. The peculiarity of this method is that it is renewable, respectively, such designs have a low cost. That is why, despite the fact that the construction of hydroelectric power plants takes quite a long time, and the process itself is very costly, nevertheless, these facilities significantly outperform electric-intensive industries.

Solar energy: modern and promising

Solar energy is obtained using solar panels, however modern technologies allow the use of new methods for this. The largest system in the world is built in the California desert. It fully provides energy for 2,000 homes. The design works as follows: the sun's rays are reflected from the mirrors, which are sent to the central boiler with water. It boils and turns into steam, which turns the turbine. It, in turn, is connected to an electric generator. The wind can also be used as the energy that the Earth gives us. The wind blows the sails, turns the windmills. And now with its help you can create devices that will generate electrical energy. By rotating the blades of the windmill, it drives the turbine shaft, which, in turn, is connected to an electric generator.

Internal energy of the Earth

It appeared as a result of several processes, the main of which are accretion and radioactivity. According to scientists, the formation of the Earth and its mass took place over several million years, and this happened due to the formation of planetesimals. They stuck together, respectively, the mass of the Earth became more and more. After our planet began to have a modern mass, but was still devoid of an atmosphere, meteoric and asteroid bodies fell on it without hindrance. This process is just called accretion, and it led to the fact that significant gravitational energy was released. And the larger bodies hit the planet, the greater the amount of energy contained in the bowels of the Earth was released.

This gravitational differentiation led to the fact that substances began to separate: heavy substances simply sank, while light and volatile substances floated up. Differentiation also affected the additional release of gravitational energy.

Atomic Energy

The use of earth energy can occur in different ways. For example, by building nuclear power plants when thermal energy is released due to the decay of the smallest particles of the matter of atoms. The main fuel is uranium, which is contained in the earth's crust. Many believe that this method of obtaining energy is the most promising, but its use is associated with a number of problems. First, uranium emits radiation that kills all living organisms. In addition, if this substance enters the soil or atmosphere, then there will be a real technological disaster. Sad consequences accidents on Chernobyl nuclear power plant we experience to this day. The danger lies in the fact that radioactive waste can threaten all living things very, very much. for a long time for millennia.

New time - new ideas

Of course, people do not stop there, and every year more and more attempts are made to find new ways to get energy. If the energy of the earth's heat is obtained quite simply, then some methods are not so simple. For example, as an energy source, it is quite possible to use biological gas, which is obtained during the decay of waste. It can be used for heating houses and heating water.

Increasingly, they are being built when dams and turbines are installed across the mouths of reservoirs, which are driven by ebbs and flows, respectively, electricity is obtained.

Burning garbage, we get energy

Another method that is already being used in Japan is the creation of incinerators. Today they are built in England, Italy, Denmark, Germany, France, the Netherlands and the USA, but only in Japan these enterprises began to be used not only for their intended purpose, but also for generating electricity. Local factories burn 2/3 of all garbage, while the factories are equipped with steam turbines. Accordingly, they supply heat and electricity to nearby areas. At the same time, in terms of costs, building such an enterprise is much more profitable than building a thermal power plant.

More tempting is the prospect of using the Earth's heat where volcanoes are concentrated. In this case, it will not be necessary to drill the Earth too deeply, since already at a depth of 300-500 meters the temperature will be at least twice as high as the boiling point of water.

There is also such a way to generate electricity as Hydrogen - the simplest and easiest chemical element- can be considered an ideal fuel, because it is where there is water. If you burn hydrogen, you can get water, which decomposes into oxygen and hydrogen. The hydrogen flame itself is harmless, that is, there will be no harm to the environment. The peculiarity of this element is that it has a high calorific value.

What's in the future?

Of course the energy magnetic field Land or the one that is received on nuclear power plants, cannot fully satisfy all the needs of mankind, which are growing every year. However, experts say that there is no reason to worry, since the planet's fuel resources are still enough. Moreover, more and more new sources are being used, environmentally friendly and renewable.

The problem of pollution remains environment, and it is growing exponentially fast. The amount of harmful emissions goes off scale, respectively, the air we breathe is harmful, the water has dangerous impurities, and the soil is gradually depleted. That is why it is so important to study in a timely manner such a phenomenon as energy in the bowels of the Earth in order to look for ways to reduce the need for fossil fuels and more actively use non-traditional sources energy.

Since ancient times, people have known about the elemental manifestations of gigantic energy lurking in the depths the globe. The memory of mankind keeps legends about catastrophic volcanic eruptions that claimed millions of human lives, unrecognizably changed the appearance of many places on Earth. The power of the eruption of even a relatively small volcano is colossal, it many times exceeds the power of the largest power plants created by human hands. True, there is no need to talk about the direct use of the energy of volcanic eruptions: people do not yet have the opportunity to curb this recalcitrant element, and, fortunately, these eruptions are quite rare events. But these are manifestations of the energy lurking in the bowels of the earth when only a tiny fraction of this inexhaustible energy finds a way out through the fire-breathing vents of volcanoes.

Small European country Iceland (the "land of ice" in literal translation) completely provides itself with tomatoes, apples and even bananas! Numerous Icelandic greenhouses are powered by the heat of the earth, there are practically no other local sources of energy in Iceland. But this country is very rich hot springs and famous geysers - fountains of hot water, with the precision of a chronometer escaping from the ground. And although Icelanders do not have priority in using the heat of underground sources (even the ancient Romans brought water from under the ground to the famous baths - the baths of Caracalla), the inhabitants of this small northern country operate the underground boiler house very intensively. The capital city of Reykjavik, where half of the country's population lives, is heated only by underground sources. Reykjavik is the ideal starting point for exploring Iceland: from here you can go on the most interesting and varied excursions to any corner of this unique country: geysers, volcanoes, waterfalls, rhyolite mountains, fjords ... Everywhere in Reykjavik you will feel PURE ENERGY - the thermal energy of geysers gushing from underground, the energy of purity and space of an ideally green city, the energy of a cheerful and incendiary nightlife Reykjavik all year round.

But not only for heating people draw energy from the depths of the earth. Power plants using hot underground springs have been operating for a long time. The first such power plant, still quite low-power, was built in 1904 in the small Italian town of Larderello, named after the French engineer Larderelli, who back in 1827 drew up a project for the use of numerous hot springs in the area. Gradually, the capacity of the power plant grew, more and more new units came into operation, new sources of hot water were used, and today the power of the station has already reached an impressive value - 360 thousand kilowatts. In New Zealand, there is such a power plant in the Wairakei region, its capacity is 160,000 kilowatts. A geothermal plant with a capacity of 500,000 kilowatts produces electricity 120 km from San Francisco in the United States.

geothermal energy

Since ancient times, people have known about the spontaneous manifestations of gigantic energy lurking in the bowels of the globe. The memory of mankind keeps legends about catastrophic volcanic eruptions that claimed millions of human lives, unrecognizably changed the appearance of many places on Earth. The power of the eruption of even a relatively small volcano is colossal, it many times exceeds the power of the largest power plants created by human hands. True, there is no need to talk about the direct use of the energy of volcanic eruptions - so far people do not have the opportunity to curb this recalcitrant element, and, fortunately, these eruptions are quite rare events. But these are manifestations of the energy lurking in the bowels of the earth, when only a tiny fraction of this inexhaustible energy finds a way out through the fire-breathing vents of volcanoes.

The geyser is hot spring, which erupts its water to regular or irregular heights, like a fountain. The name comes from the Icelandic word for "pours". The appearance of geysers requires a certain favorable environment, which was created only in a few places on earth, which leads to their rather rare presence. Almost 50% of geysers are located in the Yellowstone National Park (USA). The activity of the geyser may stop due to changes in the bowels, earthquakes and other factors. The action of a geyser is caused by the contact of water with magma, after which the water quickly heats up and, under the influence of geothermal energy, is thrown upward with force. After the eruption, the water in the geyser gradually cools, seeps back to the magma, and again gushing. The frequency of eruptions of various geysers varies from several minutes to several hours. The need for a large energy for the operation of a geyser - main reason their rarity. Volcanic areas may have hot springs, mud volcanoes, fumaroles, but there are very few places where geysers are located. The fact is that even if a geyser formed at the site of volcano activity, subsequent eruptions will destroy the surface of the earth and change its state, which will lead to the disappearance of the geyser.

Energy of the earth ( geothermal energy) is based on the use of the natural heat of the Earth. The bowels of the Earth are fraught with a colossal, almost inexhaustible source of energy. The annual radiation of internal heat on our planet is 2.8 * 1014 billion kWh. It is constantly compensated by the radioactive decay of some isotopes in the earth's crust.

Geothermal energy sources can be of two types. The first type is underground pools of natural heat carriers - hot water (hydrothermal springs), or steam (steam thermal springs), or a steam-water mixture. In essence, these are directly ready-to-use "underground boilers" from where water or steam can be extracted using ordinary boreholes. The second type is the heat of hot rocks. By pumping water into such horizons, one can also obtain steam or superheated water for further use for energy purposes.

But in both use cases main disadvantage lies, perhaps, in a very weak concentration of geothermal energy. However, in places of formation of peculiar geothermal anomalies, where hot springs or rocks come relatively close to the surface and where the temperature rises by 30-40 ° C for every 100 m deep, concentrations of geothermal energy can create conditions for its economic use. Depending on the temperature of water, steam or steam-water mixture, geothermal sources are divided into low and medium temperature (with temperatures up to 130 - 150 ° C) and high temperature (over 150 °). The nature of their use largely depends on the temperature.

It can be argued that geothermal energy has four beneficial features.

First, its reserves are practically inexhaustible. According to estimates of the late 70s, to a depth of 10 km, they amount to a value that is 3.5 thousand times higher than the reserves traditional types mineral fuel.

Secondly, geothermal energy is quite widespread. Its concentration is mainly associated with active seismic and volcanic activity, which occupy 1/10 of the Earth's area. Within these belts, some of the most promising "geothermal regions" can be distinguished, examples of which are California in the USA, New Zealand, Japan, Iceland, Kamchatka, North Caucasus in Russia. Only in former USSR by the beginning of the 1990s, about 50 underground pools of hot water and steam had been opened.

Thirdly, the use of geothermal energy does not require high costs, because. in this case we are talking about already “ready-to-use” sources of energy created by nature itself.

Finally, fourthly, geothermal energy is environmentally completely harmless and does not pollute the environment.

Man has been using the energy of the internal heat of the Earth for a long time (let us recall the famous Roman baths), but its commercial use began only in the 20s of our century with the construction of the first geoelectric power plants in Italy, and then in other countries. By the beginning of the 1980s, there were about 20 such stations operating in the world with a total capacity of 1.5 million kW. The largest of them is the Geysers station in the USA (500 thousand kW).

Geothermal energy is used to generate electricity, heat homes, greenhouses, etc. Dry steam, superheated water or any heat carrier with a low boiling point (ammonia, freon, etc.) is used as a heat carrier.

geothermal energy- this is the energy of heat that is released from the inner zones of the Earth over hundreds of millions of years. According to geological and geophysical studies, the temperature in the Earth's core reaches 3,000-6,000 °C, gradually decreasing in the direction from the center of the planet to its surface. The eruption of thousands of volcanoes, the movement of blocks of the earth's crust, earthquakes testify to the action of a powerful internal energy Earth. Scientists believe that the thermal field of our planet is due to radioactive decay in its depths, as well as the gravitational separation of the core matter.
The main sources of heating the bowels of the planet are uranium, thorium and radioactive potassium. The processes of radioactive decay on the continents occur mainly in the granitic layer of the earth's crust at a depth of 20-30 km or more, in the oceans - in the upper mantle. It is assumed that at the bottom of the earth's crust at a depth of 10-15 km, the probable temperature value on the continents is 600-800 ° C, and in the oceans - 150-200 ° C.
A person can use geothermal energy only where it manifests itself close to the Earth's surface, i.e. in areas of volcanic and seismic activity. Now geothermal energy is effectively used by such countries as the USA, Italy, Iceland, Mexico, Japan, New Zealand, Russia, the Philippines, Hungary, El Salvador. Here, the internal heat of the earth rises to the very surface in the form of hot water and steam with a temperature of up to 300 ° C and often breaks out as the heat of gushing sources (geysers), for example, the famous geysers of Yellowstone Park in the USA, geysers of Kamchatka, Iceland.
Geothermal energy sources divided into dry hot steam, wet hot steam and hot water. well, which is important source energy for electrical railway in Italy (near the city of Larderello), since 1904 it has been feeding dry hot steam. Two other well-known places in the world with hot dry steam are the Matsukawa field in Japan and the geyser field near San Francisco, where geothermal energy has also been used effectively for a long time. Most of all in the world of wet hot steam is located in New Zealand (Wairakei), geothermal fields of slightly less power - in Mexico, Japan, El Salvador, Nicaragua, Russia.
Thus, four main types of geothermal energy resources can be distinguished:
surface heat of the earth used by heat pumps;
energy resources of steam, hot and warm water near the surface of the earth, which are now used in production electrical energy;
heat concentrated deep below the surface of the earth (perhaps in the absence of water);
magma energy and heat that accumulates under volcanoes.

Geothermal heat reserves (~ 8 * 1030J) are 35 billion times the annual global energy consumption. Only 1% of the geothermal energy of the earth's crust (depth of 10 km) can provide an amount of energy that is 500 times greater than all the world's oil and gas reserves. However, today only a small part of these resources can be used, and this is due primarily to economic reasons. The beginning of the industrial development of geothermal resources (energy of hot deep waters and steam) was laid in 1916, when the first geothermal power plant with a capacity of 7.5 MW was put into operation in Italy. Over the past time, considerable experience has been accumulated in the field of practical development of geothermal energy resources. The total installed capacity of operating geothermal power plants (GeoTPP) was: 1975 - 1,278 MW, in 1990 - 7,300 MW. The United States, the Philippines, Mexico, Italy, and Japan have achieved the greatest progress in this matter.
The technical and economic parameters of the GeoTPP vary over a fairly wide range and depend on geological characteristics terrain (depth of occurrence, parameters of the working fluid, its composition, etc.). For the majority of commissioned GeoTPPs, the cost of electricity is similar to the cost of electricity produced at coal-fired TPPs, and amounts to 1200 ... 2000 US dollars / MW.
In Iceland, 80% of residential buildings are heated with hot water extracted from geothermal wells under the city of Reykjavik. In the western United States, about 180 homes and farms are heated by geothermal hot water. According to experts, between 1993 and 2000, global electricity generation from geothermal energy more than doubled. There are so many reserves of geothermal heat in the United States that it could theoretically provide 30 times more energy than the state currently consumes.
In the future, it is possible to use the heat of magma in those areas where it is located close to the Earth's surface, as well as the dry heat of heated crystalline rocks. In the latter case, wells are drilled for several kilometers, cold water is pumped down, and hot water is returned back.

The term “geothermal energy” comes from the Greek words earth (geo) and thermal (thermal). In fact, geothermal energy comes from the earth itself. Heat from the core of the earth, whose average temperature is 3600 degrees Celsius, is radiated towards the surface of the planet.

Heating of springs and geysers underground at a depth of several kilometers can be carried out using special wells through which hot water (or steam from it) flows to the surface, where it can be used directly as heat or indirectly to generate electricity by turning on rotating turbines.

Since the water below the surface of the earth is constantly replenished, and the core of the Earth will continue to generate heat relatively human life endlessly, geothermal energy, ultimately clean and renewable.

Methods for collecting energy resources of the Earth

Today, there are three main methods for harvesting geothermal energy: dry steam, hot water, and binary cycle. The dry steam process directly drives the turbine drives of the power generators. Hot water enters from the bottom up, then sprayed into the tank to create steam to drive the turbines. These two methods are the most common, generating hundreds of megawatts of electricity in the US, Iceland, Europe, Russia and other countries. But location is limited, as these plants only operate in tectonic regions where it is easier to access heated water.

With binary cycle technology, warm (not necessarily hot) water is extracted to the surface and combined with butane or pentane, which has low temperature boiling. This liquid is pumped through a heat exchanger, where it evaporates and is sent through a turbine before being recirculated back into the system. Binary cycle technology provides tens of megawatts of electricity in the US: California, Nevada and the Hawaiian Islands.

The principle of obtaining energy

Disadvantages of obtaining geothermal energy

On a utility level, geothermal power plants are costly to build and operate. For search suitable place costly well surveys are required with no guarantee of hitting a productive underground hotspot. However, analysts expect this capacity to nearly double over the next six years.

In addition, areas with a high temperature of an underground source are located in areas with active geological and chemical volcanoes. These "hot spots" formed at the boundaries of tectonic plates in places where the crust is quite thin. Pacific, often referred to as a ring of fire for many volcanoes where there are many hotspots, including those in Alaska, California, and Oregon. Nevada has hundreds of hotspots covering most northern part of the USA.

There are other seismically active areas. Earthquakes and the movement of magma allow water to circulate. In some places the water rises to the surface and natural hot springs and geysers occur, such as in Kamchatka. The water in the geysers of Kamchatka reaches 95°C.

One of the problems open system geysers is the release of some air pollutants. Hydrogen sulfide - a toxic gas with a very recognizable "rotten egg" odor - small amounts of arsenic and minerals released with steam. Salt can also pose an environmental problem.

At geothermal power plants located in the sea significant amount interfering salt accumulates in the pipes. In closed systems, there are no emissions and all liquid brought to the surface is returned.

Economic potential of the energy resource

seismically active points are not the only places where geothermal energy can be found. There is a constant supply of usable heat for direct heating purposes at depths anywhere from 4 meters to several kilometers below the surface virtually anywhere on earth. Even the land on its own backyard or at a local school has the economic potential in the form of heat to provide to the home or other buildings.

In addition, there is a huge amount of thermal energy in dry rock formations very deep below the surface (4 - 10 km).

Usage new technology could expand geothermal systems where people can use that heat to generate electricity on a much larger scale than conventional technology. The first demonstration projects of this principle of generating electricity are shown in the United States and Australia as early as 2013.

If the full economic potential of geothermal resources can be realized, it will represent a huge source of electricity for production capacity. Scientists suggest that conventional geothermal sources have a potential of 38,000 MW, which can produce 380 million MW of electricity per year.

Hot dry rocks occur at depths of 5 to 8 km everywhere underground and at shallower depths in certain places. Access to these resources involves the introduction of cold water circulating through hot rocks and the removal of heated water. Currently no commercial application this technology. Existing technologies do not yet allow to restore thermal energy directly from the magma, very deep, but it is the most powerful source of geothermal energy.

With the combination of energy resources and its consistency, geothermal energy can play an indispensable role as a cleaner, more sustainable energy system.

Constructions of geothermal power plants

Geothermal energy is clean and sustainable heat from the Earth. Larger resources range from a few kilometers below the earth's surface, and even deeper, to high-temperature molten rock called magma. But as described above, people have not yet reached the magma.

Three Geothermal Power Plant Designs

The technology of application is determined by the resource. If the water comes from the well as steam, it can be used directly. If the hot water is high enough, it must pass through the heat exchanger.

The first well for power generation was drilled before 1924. More deep wells were drilled in the 1950s, but the real development takes place in the 1970s and 1980s.

Direct use of geothermal heat

Geothermal sources can also be used directly for heating purposes. Hot water is used to heat buildings, grow plants in greenhouses, dry fish and crops, improve oil production, aid industrial processes like milk pasteurizers, and heat water in fish farms. In the US, Klamath Falls, Oregon and Boise, Idaho have used geothermal water to heat homes and buildings for over a century. On the east coast, the city of Warm Springs, Virginia receives heat directly from spring water using heat sources at one of the local resorts.

In Iceland, virtually every building in the country is heated by hot spring water. In fact, Iceland gets more than 50 percent of its primary energy from geothermal sources. In Reykjavik, for example (pop. 118,000), hot water is conveyed 25 kilometers along a conveyor, and residents use it for heating and natural needs.

New Zealand gets 10% of its electricity extra. is underdeveloped, despite the presence of thermal waters.