When the ground warms up at a depth of 2 meters. Earth vertical collectors
To model temperature fields and for other calculations, it is necessary to know the temperature of the soil at a given depth.
Soil temperature at depth is measured using exhaust soil-depth thermometers. These are planned studies that are regularly carried out by meteorological stations. Research data serves as the basis for climate atlases and regulatory documentation.
To obtain the soil temperature at a given depth, you can try, for example, two simple methods. Both methods involve using reference books:
- For an approximate determination of temperature, you can use the document TsPI-22. "Transitions of railways by pipelines." Here, within the framework of the methodology for thermal engineering calculation of pipelines, Table 1 is given, where for certain climatic regions the values of soil temperatures are given depending on the measurement depth. I present this table here below.
Table 1
- Table of soil temperatures at various depths from a source “to help a gas industry worker” from USSR times
Standard freezing depths for some cities:
The depth of soil freezing depends on the type of soil:
I think the easiest option is to use the above reference data and then interpolate.
The most reliable option for accurate calculations using ground temperatures is to use data from meteorological services. Some online directories operate on the basis of meteorological services. For example, http://www.atlas-yakutia.ru/.
Here you just need to select a settlement, soil type, and you can get a soil temperature map or its data in tabular form. In principle, it’s convenient, but it looks like this resource is paid.
If you know other ways to determine the soil temperature at a given depth, then please write comments.
You may be interested in the following material:
Instead of a foreword.
Smart and friendly people pointed out to me that this case should be assessed only in a non-stationary setting, due to the enormous thermal inertia of the earth, and take into account the annual regime of temperature changes. The completed example was solved for a stationary thermal field, therefore it has obviously incorrect results, so it should be considered only as some kind of idealized model with a huge number of simplifications showing the temperature distribution in a stationary mode. So, as they say, any coincidence is pure coincidence...
***************************************************
As usual, I will not give a lot of specifics about the accepted thermal conductivities and thicknesses of materials, I will limit myself to describing only a few, we assume that other elements are as close as possible to real structures - the thermophysical characteristics are assigned correctly, and the thicknesses of materials are adequate to real cases of construction practice. The purpose of the article is to obtain a framework understanding of the temperature distribution at the Building-Ground boundary under various conditions.
A little about what needs to be said. The calculated schemes in this example contain 3 temperature boundaries, the 1st is the internal air of the premises of the heated building +20 o C, the 2nd is the outside air -10 o C (-28 o C), and the 3rd is the temperature in the soil thickness at a certain depth, at which it fluctuates around a certain constant value. In this example, the value of this depth is assumed to be 8 m and the temperature is +10 o C. Here someone can argue with me regarding the accepted parameters of the 3rd boundary, but a dispute about the exact values is not the purpose of this article, just as the results obtained are not claim to be particularly accurate and can be linked to a specific design case. I repeat, the task is to obtain a fundamental, framework understanding of the temperature distribution, and to test some established ideas on this issue.
Now let's get straight to the point. So these are the points that need to be tested.
1. The soil under the heated building has a positive temperature.
2. Standard depth of soil freezing (this is more of a question than a statement). Is the snow cover of the ground taken into account when providing data on freezing in geological reports, because as a rule, the area around the house is cleared of snow, paths, sidewalks, blind areas, parking, etc. are cleaned?
Soil freezing is a process over time, so for calculation we will take the outside temperature equal to the average temperature of the coldest month -10 o C. We will take the soil with the reduced lambda = 1 for the entire depth.
Fig.1. Calculation scheme.
Fig.2. Temperature isolines. Scheme without snow cover.
In general, the ground temperature under the building is positive. Maximums are closer to the center of the building, minimums are towards the outer walls. The horizontal zero temperature isoline only touches the projection of the heated room onto the horizontal plane.
Freezing of the soil away from the building (i.e., reaching negative temperatures) occurs at a depth of ~2.4 meters, which is greater than the standard value for the conditionally selected region (1.4-1.6 m).
Now let's add 400mm of medium-density snow with lambda 0.3.
Fig.3. Temperature isolines. Scheme with 400mm snow cover.
Isolines of positive temperatures displace negative temperatures outward; under the building there are only positive temperatures.
Ground freezing under snow cover is ~1.2 meters (-0.4 m of snow = 0.8 m of ground freezing). The snow “blanket” significantly reduces the freezing depth (almost 3 times).
Apparently the presence of snow cover, its height and degree of compaction is not a constant value, therefore the average freezing depth is in the range of the results obtained from the 2 schemes, (2.4 + 0.8) * 0.5 = 1.6 meters, which corresponds to the standard value.
Now let's see what happens if severe frosts hit (-28 o C) and remain long enough for the thermal field to stabilize, while there is no snow cover around the building.
Fig.4. Scheme at -28 O With no snow cover.
Negative temperatures crawl under the building, positive temperatures are pressed against the floor of the heated room. In the area of foundations, the soil freezes. At a distance from the building, the soil freezes to ~4.7 meters.
See previous blog posts.
Imagine a home that is always kept at a comfortable temperature, with no heating or cooling systems in sight. This system works efficiently, but does not require complex maintenance or special knowledge from owners.
The air is fresh, you can hear the birds chirping and the wind lazily playing with the leaves on the trees. The house receives energy from the earth, just like leaves receive energy from the roots. A wonderful picture, isn't it?
Geothermal heating and cooling systems make this vision a reality. A geothermal HVAC (heating, ventilation and air conditioning) system uses the ground's temperature to provide heating in the winter and cooling in the summer.
How Geothermal Heating and Cooling Works
The ambient temperature changes with the seasons, but the underground temperature does not change as significantly due to the insulating properties of the earth. At a depth of 1.5-2 meters, the temperature remains relatively constant all year round. A geothermal system typically consists of internal treatment equipment, an underground pipe system called an underground loop, and/or a pump to circulate the water. The system uses the constant temperature of the earth to provide "clean and free" energy.
(Do not confuse the concept of a geothermal NVC system with "geothermal energy" - a process in which electricity is produced directly from high temperatures in the ground. The latter uses a different type of equipment and different processes, the purpose of which is usually to heat water to the boiling point.)
The pipes that make up the underground loop are usually made of polyethylene and can be installed horizontally or vertically underground, depending on the terrain. If an aquifer is accessible, engineers can design an "open loop" system by drilling a well to the groundwater. The water is pumped out, passed through a heat exchanger, and then reinjected into the same aquifer through “re-injection.”
In winter, water passing through an underground loop absorbs the heat of the earth. Internal equipment further increases the temperature and distributes it throughout the building. It's like an air conditioner working in reverse. During the summer, a geothermal HVAC system draws high-temperature water from the building and carries it through an underground loop/pump to a re-injection well, where the water flows into the cooler ground/aquifer.
Unlike conventional heating and cooling systems, geothermal HVAC systems do not use fossil fuels to generate heat. They simply take heat from the ground. Typically, electricity is used only to operate the fan, compressor and pump.
There are three main components in a geothermal cooling and heating system: the heat pump, the heat exchange fluid (open-loop or closed-loop system), and the air supply system (piping system).
For geothermal heat pumps, as well as for all other types of heat pumps, the ratio of their useful action to the energy expended for this action (efficiency) was measured. Most geothermal heat pump systems have an efficiency of 3.0 to 5.0. This means that the system converts one unit of energy into 3-5 units of heat.
Geothermal systems do not require high maintenance. Properly installed, which is very important, an underground loop can serve well for several generations. The fan, compressor and pump are housed indoors and protected from changing weather conditions, so their service life can last for many years, often decades. Routine periodic checks, timely filter replacement and annual coil cleaning are the only maintenance required.
Experience in using geothermal NVC systems
Geothermal NVC systems have been used for more than 60 years all over the world. They work with nature, not against it, and they don't emit greenhouse gases (as noted earlier, they use less electricity because they take advantage of the constant temperature of the earth).
Geothermal HVAC systems are increasingly becoming attributes of eco-friendly homes, as part of the growing green building movement. Green projects accounted for 20 percent of all homes built in the United States last year. An article in the Wall Street Journal estimates that by 2016, the green building budget will grow from $36 billion per year to $114 billion. This will account for 30-40 percent of the entire real estate market.
But much of the information about geothermal heating and cooling is based on outdated data or unsubstantiated myths.
Busting myths about geothermal NVC systems
1. Geothermal NVC systems are not a renewable technology because they use electricity.
Fact: Geothermal HVAC systems use only one unit of electricity to produce up to five units of cooling or heating.
2. Solar energy and wind energy are more favorable renewable technologies compared to geothermal NVC systems.
Fact: Geothermal HVAC systems for one dollar generate four times more kilowatt-hours than solar or wind energy produces for the same dollar. These technologies can, of course, play an important role for the environment, but a geothermal NVC system is often the most effective and economical way to reduce environmental impact.
3. A geothermal NVC system requires a lot of space to accommodate the underground loop polyethylene pipes.
Fact: Depending on the terrain, the underground loop may be vertical, meaning little surface area is required. If there is an accessible aquifer, then only a few square feet of surface area are needed. Note that the water returns to the same aquifer from which it was taken after passing through the heat exchanger. Thus, the water is not runoff and does not pollute the aquifer.
4. NVK geothermal heat pumps are noisy.
Fact: The systems are very quiet and there is no equipment outside to avoid disturbing the neighbors.
5. Geothermal systems eventually wear out.
Fact: Underground loops can last for generations. Heat exchange equipment typically lasts for decades because it is protected indoors. When it comes time to replace equipment, the replacement cost is much less than a new geothermal system because the underground loop and well are the most expensive parts. New technical solutions eliminate the problem of heat retention in the ground, so the system can exchange temperatures in unlimited quantities. There have been cases in the past of missized systems that actually overheated or undercooled the ground to the point that there was no longer the temperature difference needed for the system to operate.
6. Geothermal NVC systems work only for heating.
Fact: They work just as efficiently for cooling and can be designed so that there is no need for an additional backup heat source. Although some customers decide that it is more cost effective to have a small backup system for the coldest times. This means their underground loop will be smaller and therefore cheaper.
7. Geothermal HVAC systems cannot simultaneously heat water for domestic purposes, heat the water in the pool and heat the house.
Fact: Systems can be designed to perform many functions simultaneously.
8. Geothermal NVC systems pollute the earth with refrigerants.
Fact: Most systems use only water in the loops.
9. Geothermal NVC systems use a lot of water.
Fact: Geothermal systems actually use no water. If groundwater is used to exchange temperature, then all the water returns to the same aquifer. There were indeed some systems used in the past that wasted water after it passed through the heat exchanger, but such systems are hardly used today. If you look at the issue from a commercial point of view, geothermal NVC systems actually save millions of liters of water that would evaporate in traditional systems.
10. Geothermal NVC technology is not financially feasible without state and regional tax incentives.
Fact: State and regional incentives typically account for 30 to 60 percent of the total cost of a geothermal system, which can often bring the initial price down to almost the same level as conventional equipment. Standard HVAC air systems cost approximately $3,000 per ton of heat or cold (homes typically use one to five tons). The price of geothermal NVC systems ranges from approximately $5,000 per ton to 8,000-9,000. However, new installation methods significantly reduce costs, down to the prices of conventional systems.
Cost reductions can also be achieved through discounts on equipment for public or commercial use, or even large orders of a residential nature (especially from large brands such as Bosch, Carrier and Trane). Open loops, using a pump and reinjection well, are cheaper to install than closed loop systems.
Based on materials from: energyblog.nationalgeographic.com
One of the best, most rational methods in the construction of permanent greenhouses is an underground thermos greenhouse.
Using this fact of the constancy of the earth's temperature at depth in the construction of a greenhouse provides enormous savings on heating costs in the cold season, makes maintenance easier, and makes the microclimate more stable..
Such a greenhouse works in the bitterest frosts and allows you to produce vegetables and grow flowers all year round.
A properly equipped in-ground greenhouse makes it possible to grow, among other things, heat-loving southern crops. There are practically no restrictions. Citrus fruits and even pineapples can thrive in a greenhouse.
But in order for everything to function properly in practice, it is imperative to follow the time-tested technologies used to build underground greenhouses. After all, this idea is not new; even under the Tsar in Russia, sunken greenhouses produced pineapple harvests, which enterprising merchants exported for sale to Europe.
For some reason, the construction of such greenhouses has not become widespread in our country; by and large, it has simply been forgotten, although the design is ideal for our climate.
Probably, the need to dig a deep pit and pour the foundation played a role here. The construction of a buried greenhouse is quite expensive; it is far from being a greenhouse covered with polyethylene, but the return from the greenhouse is much greater.
The total internal illumination is not lost from being buried in the ground; this may seem strange, but in some cases the light saturation is even higher than that of classic greenhouses.
It is impossible not to mention the strength and reliability of the structure; it is incomparably stronger than usual, it can more easily withstand hurricane gusts of wind, it resists hail well, and snow debris will not become a hindrance.
1. Pit
Creating a greenhouse begins with digging a pit. To use the heat of the earth to heat the interior, the greenhouse must be deep enough. The deeper you go, the warmer the earth becomes.
The temperature remains almost unchanged throughout the year at a distance of 2-2.5 meters from the surface. At a depth of 1 m, the soil temperature fluctuates more, but even in winter its value remains positive; usually in the middle zone the temperature is 4-10 C, depending on the time of year.
A recessed greenhouse is built in one season. That is, in winter it will be fully able to function and generate income. Construction is not cheap, but by using ingenuity and compromise materials, it is possible to save literally an order of magnitude by making a kind of economical version of a greenhouse, starting from the foundation pit.
For example, do without the use of construction equipment. Although the most labor-intensive part of the work - digging a pit - is, of course, better to give it to an excavator. Manually removing such a volume of soil is difficult and time-consuming.
The depth of the excavation pit must be at least two meters. At such a depth, the earth will begin to share its heat and work like a kind of thermos. If the depth is less, then in principle the idea will work, but noticeably less effectively. Therefore, it is recommended not to spare effort and money on deepening the future greenhouse.
Underground greenhouses can be any length, but it is better to keep the width within 5 meters; if the width is larger, the quality characteristics of heating and light reflection deteriorate.
On the sides of the horizon, underground greenhouses must be oriented, like ordinary greenhouses and greenhouses, from east to west, that is, so that one of the sides faces south. In this position, the plants will receive the maximum amount of solar energy.
2. Walls and roof
A foundation is poured or blocks are laid around the perimeter of the pit. The foundation serves as the basis for the walls and frame of the structure. It is better to make walls from materials with good thermal insulation characteristics; thermal blocks are an excellent option.
The roof frame is often made of wood, from bars impregnated with antiseptic agents. The roof structure is usually straight gable. A ridge beam is fixed in the center of the structure; for this, central supports are installed on the floor along the entire length of the greenhouse.
The ridge beam and the walls are connected by a series of rafters. The frame can be made without high supports. They are replaced with small ones, which are placed on transverse beams connecting opposite sides of the greenhouse - this design makes the internal space freer.
As a roof covering, it is better to take cellular polycarbonate - a popular modern material. The distance between the rafters during construction is adjusted to the width of the polycarbonate sheets. It is convenient to work with the material. The coating is obtained with a small number of joints, since the sheets are produced 12 m long.
They are attached to the frame with self-tapping screws; it is better to choose them with a washer-shaped cap. To avoid cracking of the sheet, you need to drill a hole of the appropriate diameter for each self-tapping screw. Using a screwdriver or a regular drill with a Phillips bit, the glazing work moves very quickly. In order to ensure that there are no gaps left, it is good to lay a sealant made of soft rubber or other suitable material along the top of the rafters in advance and only then screw the sheets. The peak of the roof along the ridge needs to be laid with soft insulation and pressed with some kind of corner: plastic, tin, or other suitable material.
For good thermal insulation, the roof is sometimes made with a double layer of polycarbonate. Although the transparency is reduced by about 10%, it is covered by excellent thermal insulation performance. It should be taken into account that snow on such a roof does not melt. Therefore, the slope must be at a sufficient angle, at least 30 degrees, so that snow does not accumulate on the roof. Additionally, an electric vibrator is installed for shaking; it will protect the roof if snow does accumulate.
Double glazing is done in two ways:
A special profile is inserted between two sheets, the sheets are attached to the frame from above;
First, the bottom layer of glazing is attached to the frame from the inside, to the underside of the rafters. The second layer of the roof is covered, as usual, from above.
After completing the work, it is advisable to seal all joints with tape. The finished roof looks very impressive: without unnecessary joints, smooth, without protruding parts.
3. Insulation and heating
Wall insulation is carried out as follows. First you need to carefully coat all the joints and seams of the wall with the solution; here you can also use polyurethane foam. The inside of the walls is covered with thermal insulation film.
In cold parts of the country, it is good to use thick foil film, covering the wall with a double layer.
The temperature deep in the soil of the greenhouse is above freezing, but colder than the air temperature necessary for plant growth. The top layer is heated by the sun's rays and the air of the greenhouse, but still the soil takes away heat, so often in underground greenhouses they use the technology of “warm floors”: the heating element - an electric cable - is protected with a metal grate or filled with concrete.
In the second case, soil for the beds is poured on top of concrete or greens are grown in pots and flowerpots.
The use of underfloor heating can be sufficient to heat the entire greenhouse, if there is enough power. But it is more effective and more comfortable for plants to use combined heating: warm floor + air heating. For good growth, they need an air temperature of 25-35 degrees with a ground temperature of approximately 25 C.
CONCLUSION
Of course, building a recessed greenhouse will cost more and require more effort than building a similar greenhouse of a conventional design. But the money invested in a thermos greenhouse pays off over time.
Firstly, it saves energy on heating. No matter how a conventional above-ground greenhouse is heated in winter, it will always be more expensive and more difficult than a similar heating method in an underground greenhouse. Secondly, saving on lighting. Foil thermal insulation of the walls, reflecting light, doubles the illumination. The microclimate in a deep greenhouse in winter will be more favorable for plants, which will certainly affect the yield. The seedlings will take root easily, and delicate plants will feel great. Such a greenhouse guarantees a stable, high yield of any plants all year round.
Kirill Degtyarev, researcher, Moscow State University. M. V. Lomonosov.
In our country, rich in hydrocarbons, geothermal energy is a kind of exotic resource, which, given the current state of affairs, is unlikely to compete with oil and gas. However, this alternative type of energy can be used almost everywhere and quite effectively.
Photo by Igor Konstantinov.
Changes in soil temperature with depth.
An increase in the temperature of thermal waters and dry rocks containing them with depth.
Temperature changes with depth in different regions.
The eruption of the Icelandic volcano Eyjafjallajokull is an illustration of violent volcanic processes occurring in active tectonic and volcanic zones with a powerful heat flow from the bowels of the earth.
Installed capacities of geothermal power plants by country, MW.
Distribution of geothermal resources throughout Russia. Geothermal energy reserves, according to experts, are several times greater than the energy reserves of organic fossil fuels. According to the Geothermal Energy Society.
Geothermal energy is the heat of the earth's interior. It is produced in the depths and reaches the surface of the Earth in different forms and with different intensities.
The temperature of the upper layers of the soil depends mainly on external (exogenous) factors - solar illumination and air temperature. In summer and during the day, the soil warms up to certain depths, and in winter and at night it cools down following changes in air temperature and with some delay that increases with depth. The influence of daily fluctuations in air temperature ends at depths from a few to several tens of centimeters. Seasonal fluctuations affect deeper layers of soil - up to tens of meters.
At some depth - from tens to hundreds of meters - the soil temperature remains constant, equal to the average annual air temperature at the Earth's surface. You can easily verify this by going down into a fairly deep cave.
When the average annual air temperature in a given area is below zero, it manifests itself as permafrost (more precisely, permafrost). In Eastern Siberia, the thickness, that is, the thickness, of year-round frozen soils in some places reaches 200-300 m.
From a certain depth (different for each point on the map), the action of the Sun and the atmosphere weakens so much that endogenous (internal) factors come first and the earth’s interior heats up from the inside, so that the temperature begins to rise with depth.
The heating of the deep layers of the Earth is associated mainly with the decay of radioactive elements located there, although other heat sources are also called, for example, physicochemical, tectonic processes in the deep layers of the earth's crust and mantle. But whatever the reason, the temperature of rocks and associated liquid and gaseous substances increases with depth. Miners face this phenomenon - it is always hot in deep mines. At a depth of 1 km, thirty-degree heat is normal, and deeper the temperature is even higher.
The heat flow of the earth's interior reaching the Earth's surface is small - on average its power is 0.03-0.05 W/m2,
or approximately 350 Wh/m2 per year. Against the background of the heat flow from the Sun and the air heated by it, this is an unnoticeable value: the Sun gives each square meter of the earth's surface about 4000 kWh annually, that is, 10,000 times more (of course, this is on average, with a huge spread between the polar and equatorial latitudes and depending on other climatic and weather factors).
The insignificance of heat flow from the interior to the surface in most of the planet is associated with the low thermal conductivity of rocks and the peculiarities of the geological structure. But there are exceptions - places where the heat flow is high. These are, first of all, zones of tectonic faults, increased seismic activity and volcanism, where the energy of the earth’s interior finds an outlet. Such zones are characterized by thermal anomalies of the lithosphere; here the heat flow reaching the Earth’s surface can be several times and even orders of magnitude more powerful than “usual”. Volcanic eruptions and hot springs bring enormous amounts of heat to the surface in these zones.
These are the areas that are most favorable for the development of geothermal energy. On the territory of Russia, these are, first of all, Kamchatka, the Kuril Islands and the Caucasus.
At the same time, the development of geothermal energy is possible almost everywhere, since an increase in temperature with depth is a universal phenomenon, and the task is to “extract” heat from the depths, just as mineral raw materials are extracted from there.
On average, temperature increases with depth by 2.5-3 o C for every 100 m. The ratio of the temperature difference between two points lying at different depths to the difference in depths between them is called the geothermal gradient.
The reciprocal value is the geothermal stage, or the depth interval at which the temperature rises by 1 o C.
The higher the gradient and, accordingly, the lower the stage, the closer the heat of the Earth’s depths comes to the surface and the more promising this area is for the development of geothermal energy.
In different areas, depending on the geological structure and other regional and local conditions, the rate of temperature increase with depth can vary dramatically. On an Earth scale, fluctuations in the magnitudes of geothermal gradients and steps reach 25 times. For example, in Oregon (USA) the gradient is 150 o C per 1 km, and in South Africa - 6 o C per 1 km.
The question is, what is the temperature at great depths - 5, 10 km or more? If the trend continues, the temperature at a depth of 10 km should average approximately 250-300 o C. This is more or less confirmed by direct observations in ultra-deep wells, although the picture is much more complicated than a linear increase in temperature.
For example, in the Kola superdeep well, drilled in the Baltic crystalline shield, the temperature to a depth of 3 km changes at a rate of 10 o C/1 km, and then the geothermal gradient becomes 2-2.5 times greater. At a depth of 7 km, a temperature of 120 o C was already recorded, at 10 km - 180 o C, and at 12 km - 220 o C.
Another example is a well drilled in the Northern Caspian region, where at a depth of 500 m a temperature of 42 o C was recorded, at 1.5 km - 70 o C, at 2 km - 80 o C, at 3 km - 108 o C.
It is assumed that the geothermal gradient decreases starting from a depth of 20-30 km: at a depth of 100 km, the estimated temperatures are about 1300-1500 o C, at a depth of 400 km - 1600 o C, in the Earth's core (depths more than 6000 km) - 4000-5000 o WITH.
At depths of up to 10-12 km, temperature is measured through drilled wells; where they are not present, it is determined by indirect signs in the same way as at greater depths. Such indirect signs may be the nature of the passage of seismic waves or the temperature of the erupting lava.
However, for the purposes of geothermal energy, data on temperatures at depths of more than 10 km are not yet of practical interest.
There is a lot of heat at depths of several kilometers, but how to raise it? Sometimes nature itself solves this problem for us with the help of a natural coolant - heated thermal waters that come to the surface or lie at a depth accessible to us. In some cases, the water in the depths is heated to the state of steam.
There is no strict definition of the concept of “thermal waters”. As a rule, they mean hot underground waters in a liquid state or in the form of steam, including those that come to the surface of the Earth with a temperature above 20 o C, that is, as a rule, higher than the air temperature.
The heat of underground water, steam, steam-water mixtures is hydrothermal energy. Accordingly, energy based on its use is called hydrothermal.
The situation is more complicated with the extraction of heat directly from dry rocks - petrothermal energy, especially since fairly high temperatures, as a rule, begin from depths of several kilometers.
On the territory of Russia, the potential of petrothermal energy is one hundred times higher than that of hydrothermal energy - 3,500 and 35 trillion tons of standard fuel, respectively. This is quite natural - the warmth of the depths of the Earth is available everywhere, and thermal waters are found locally. However, due to obvious technical difficulties, thermal waters are currently mostly used to generate heat and electricity.
Water with temperatures from 20-30 to 100 o C is suitable for heating, with temperatures from 150 o C and above - and for generating electricity at geothermal power plants.
In general, geothermal resources in Russia, in terms of tons of equivalent fuel or any other unit of energy measurement, are approximately 10 times higher than fossil fuel reserves.
Theoretically, only geothermal energy could fully satisfy the country's energy needs. In practice, at the moment, in most of its territory this is not feasible for technical and economic reasons.
In the world, the use of geothermal energy is most often associated with Iceland, a country located at the northern end of the Mid-Atlantic Ridge, in an extremely active tectonic and volcanic zone. Everyone probably remembers the powerful eruption of the Eyjafjallajökull volcano in 2010.
It is thanks to this geological specificity that Iceland has huge reserves of geothermal energy, including hot springs that emerge on the surface of the Earth and even gush out in the form of geysers.
In Iceland, over 60% of all energy consumed currently comes from the Earth. Geothermal sources provide 90% of heating and 30% of electricity generation. Let us add that the rest of the country’s electricity is produced by hydroelectric power plants, that is, also using a renewable energy source, making Iceland look like a kind of global environmental standard.
The domestication of geothermal energy in the 20th century greatly benefited Iceland economically. Until the middle of the last century, it was a very poor country, now it ranks first in the world in terms of installed capacity and production of geothermal energy per capita and is in the top ten in absolute value of installed capacity of geothermal power plants. However, its population is only 300 thousand people, which simplifies the task of switching to environmentally friendly energy sources: the need for it is generally small.
In addition to Iceland, a high share of geothermal energy in the overall balance of electricity production is provided in New Zealand and the island countries of Southeast Asia (Philippines and Indonesia), countries of Central America and East Africa, the territory of which is also characterized by high seismic and volcanic activity. For these countries, at their current level of development and needs, geothermal energy makes a significant contribution to socio-economic development.
(The ending follows.)
