Cheap safe ecological but rare way to generate electricity on a commercial scale

After Chernobyl, the world is not scared and did not stop the construction of nuclear power plants. The world has decided, perhaps, that it worked specifically Soviet human factor. After the disaster at the nuclear power plant «Fukushima» in Japan, mankind has realized that nuclear power is dangerous, even in the hands of careful, responsible, and technologically advanced civilizations. Germany and other EU countries are already thinking about a complete cessation of the use of nuclear power plants. Therefore, the search for new, safer energy sources is as relevant as ever. One source could be the heat of the earth.

Sitting in the hot-water bottle

Under the outer shell of the Earth — the Earth’s crust — is heated by the mantle, which may originate volcanoes (on other theories, volcanoes originate in foreign shell molten core). Hot magma rises along tectonic fractures and is in contact with the ocean water that infiltrated from the bottom of the ocean in areas okolomagmaticheskie zone. There the water is heated, absorbs part of the dissolved gases in the magma — such as hydrogen sulfide and carbon dioxide — and other chemicals, and grabbing items from the rocks through which it is filtered. The increase in CO2 causes the formation of a strong adsorbent — calcium silica, which leads to changes in the permeability of the water-bearing complexes and, ultimately, to the thermal and geochemical isolation geothermal system. It is believed that the presence of silica leads to high concentrations of various substances in the thermal waters.

On the continents crust is usually very strong — up to 70, sometimes up to 100 kilometers. The older igneous rocks are usually covered with a thick sedimentary cover, and its magma just break. However, where the crust is thinner — for example, in the areas of transition from continental to oceanic crust — magma, hot gases and superheated water vapor is easier to get to the surface. It is in these areas occur most interesting geological events of our day — volcanic eruptions, earthquakes, that’s where snort and spit geysers, fumaroles, smoke, and that there is relatively easy access to the underground heat sources. Actually, the most active volcanic manifestations occur in areas where the crust is thinnest — at the bottom of the oceans, in the areas of the mid-ocean ridges, but neither see nor really to study, let alone use the volcanism we have not yet learned.

The main part of the territory of Russia is located on the two ancient, 2.5 — 3.5 billion years, the platforms (the East European and Siberian). Between them is a relatively young (only 250-400 million years), but also a reliable West Siberian plate. Therefore, in areas with Russia are only a thin crust on the far outskirts — Kamchatka and the Kuril Islands, which are part of the zone of active geological processes. «In areas of modern volcanism and geothermal deposits are formed, — says Doctor of Geological and Mineralogical Sciences, head of the laboratory heat and mass IVS FED Alex Kiryukhin. — The conditions of their formation can be different. Quite often works: the more and more active volcano, the less chance of finding in the vicinity of geothermal field (example — Klyuchevskaya), the larger the geothermal field, the less likely to see within it a large volcano (example — the Valley of Geysers in California). «

Pacific margin form the Pacific Ring of Fire. Fire it because here for the majority of the active volcanoes. Here there is subductionEnlarge

For contemporary active volcanism are concentrated in the so-called Pacific Ring of Fire — it’s almost all of the Pacific margin, including Kamchatka, Kuril Islands, Japan, Indonesia, the Philippines, the Andes and the Cordillera, the chain of the Aleutian Islands and the archipelago of Tierra del Fuego. All these areas are zones of the youngest, Alpine folding, and the edges of the continents are subject to a process of subduction — underthrusting oceanic crust under the continental. In the process of subduction of continental crust marginal parts soar, forming ridges, and «dive» frontal zone thin oceanic crust melts, giving the «raw material» for the modern volcanoes.

Zones of Alpine folding also include the Alps and the Pyrenees, the Crimea, the Caucasus, Pamir, Himalayas. Many volcanoes have been active here for a stage, and in the rocks overlying the cooling magma, occur post-magmatic processes. In such areas, fading or «dormant» volcanism — which manifests itself not so much eruptions as the work of geysers, fumaroles, mud volcanoes — just it is possible to generate electricity on a commercial scale. In other, less active areas, however, also possible to use the earth’s heat. Even in stable platform regions there are thermal springs, and geothermal gradient can be quite high.

Creative, cheap and clean technology

Use geothermal heat can be different. First, as the ancient Romans, can be used directly to heat the thermal waters and baths. Countless hot springs in Europe, whether in America, in the Philippines — are manifestations of the same post-volcanic processes. In Russia, the heat of underground water is used to heat buildings and greenhouses in the Kaliningrad region, Western Siberia, in the Krasnodar region. This «direct» use of heat saving and reduce the load on the environment.

You can use heat pumps, which allow heat or cool homes due to the difference in temperature between the air and the ground. And you can — in addition to simply heat — to build a geothermal power plant and get a very cheap electricity. Depending on the geological conditions — that is, the temperature of rocks and the presence and composition of the water in them — may use different types gidrotermoelektrostantsy.

In some cases, geothermal energy can kill several birds with one stone. For example, «Chevron» uses for its production of hot water is pumped from the depths along with the oil. On the surface of a hot mixture of water and steam is separated from the oil is separated, steam and drive a turbine provides electricity, water is pumped back into the formation. This allows you to solve the problem of toxic discharges and maintain the pressure in the oil reservoir, thereby improving its oil recovery and extending the use of the well.

Geothermal energy, a new branch at the junction of several sciences and industry, attracted the attention of scholars and practitioners of various specialties. Some are thinking how to get the rare and noble metals, dissolved in hot groundwater. Maybe it was in the cooling phase of the water someday and be able to remove the gold and platinum.

Others invent ways to use low-temperature water. Chief Engineer of «Geoterm» Dmitry Kolesnikov believes that the technology will soon be recycling separator, that is partially chilled water: «It can be used on all types of industrial plants where there are hot stocks. More power should be expected, but in- First, the hot water goes to the second cycle, that is, reduced non-productive use of energy, and secondly, it will be possible to solve the problem of energy supply of the enterprise itself. «

Russia is stable

Geothermal power in Russia began to develop in the 1960s. Then constructed the first — in fact, experimental — power. Pauzhetskaya Geothermal Power Plant (11 MW), on the same geothermal field was built in 1967. «This plant served as a pilot site for its proven technologies, tested steam-water mixture,» — said Kolesnikov. Far from it are Mutnovskaya GeoPP (50 MW) and Upper Mutnovskaya (12 MW) geothermal power plant. In the Kuril Islands, the islands of Kunashir and Iturup, also has two relatively small geothermal power plant — 6 and 2.6 MW. Actually, this rather short list, and restricts the actions of the Russian geothermal energy.

Not because of the political-economic and historical reasons, not because the overseas head or better technology, but only because of the high stability of the Russian geological unit western, eastern, southeastern, and even some African countries have left us far behind in the field of geothermal energy. In Iceland, geothermal power plants are 30% of the electricity in the Philippines — more than 25%, El Salvador and Costa Rica — about 15%, in New Zealand, Nicaragua — 10%. In the U.S., the proportion of «geothermal» electricity is low, only 0.3%, but in terms of making the United States ahead of the rest of the world.

In the U.S., a well-known geothermal power plants in California and Nevada in 2006, added a small but unusual power in the most that neither is a deep American heartland — in Alaska, in the resort China Hot Springs. Although the hot springs there are hot for humans (74S), the temperature is still too low to generate power for the conventional technology. However, the decision — application of the binary cycle — was found: in the heat exchanger natural water gives heat specific reagent, which boils even at such a low temperature. Slightly chilled (about 70 degrees), the water is returned to the original fair horizon. In five years of operation, the incoming water temperature dropped about a degree. Three generators can produce 650 kW per hour, which is sufficient, for example, to serve the whole village. Each generator is worth about $ 800,000, and the payback in six months is not expected. But for 10 years, this investment will pay off, even if the price of electricity at 6 cents per kilowatt. Generator that runs on fuel oil, «cost» 30 cents per kilowatt, so the difference is obvious.

A binary technology used in Alaska, actually invented in Russia in 1967, and used to Paratunski geothermal field in Kamchatka.

Economy hot water

According to Dmitry Kolesnikov, the benefits of geothermal energy — in the simplicity of the process and low cost of the received energy. «Actually, the well is drilled, of which there is a steam-water mixture, which is separated at the plant, the steam turns a turbine, and then everything works like a standard boiler,» — he explained how it works.

Geothermal energy is really very cheap costs, primarily due to savings on hydrocarbons. The most expensive — is well and power lines. True, there is where you can build hydropower, geothermal power will not be as economically attractive. But in Russia, the most powerful hydropower plant built when the concept of private ownership of land was not. Today, in order to flood the huge territory, you will need someone to buy them, which greatly raise the price of a kilowatt-hour. And sorry for the ground (so modern hydro built mostly in the mountains, where the area of flooding is minimal). But when comparing the cost of «geothermal» kilowatt-hour to the price of electricity generated by thermal power plants, the difference is now not in favor of hydrocarbon energy.

Ecology of salt water

People who engage in geothermal energy, once admired for her concern. They understand that this is a relatively cheap, relatively safe way to generate electricity from renewable sources. However, as in all industries, there are some problems.

Yes, fossil fuels to geothermal power plant there, but there is the problem of waste. «Waste» — is cooled down underground water, often very salty. It can not be reset to a nearby river, it is too toxic. In addition, the removal of material from the bowels normally increase seismic activity, and because of the influx of seismic dislocations water mixture to the surface may even stop. «The waters have (at Pauzhetskaya power) — 1,000 tons per hour, should ideally be a closed loop, on the surface, we pour this water can not. Water — separatrix — we pump into the reservoir. Though not in the place where we take it, or we will rapidly cool the «giving» site. therefore not upload to it, and in adjacent areas, «- says Kolesnikov.

Due to the highly corrosive hot groundwater is a problem of corrosion, wear and tear. But corrosion, according to Kolesnikov, fight you can — you just have to choose the right materials.

Geothermal energy is not always easy to obtain. Often geothermal fields are located in remote areas or in areas of high seismic activity. In seismically active zones of the geothermal power plant construction is not only fraught with danger for the workers, but it may not be economically meaningless: the shifting of structural geothermal field may simply disappear or change the mode so that the work station will become unprofitable.

Geotherm generally not well understood. Surface, more readily available geotherm often have a relatively short life span. Investigations of the deep-seated, larger geothermal fields require large resources. While Russia’s economy is living through high prices for hydrocarbons, research and practical work in the geotherm remain underfunded. This will lead to the fact that Russia, once the first to use binary technology, will once again be in the tail, as well as shale gas.

«We want to, do not want, and will develop»

It is unlikely that geothermal energy will come to every home. In Russia, at least, not tomorrow. Low-temperature technology for electricity is still expensive, and most importantly — in platform areas, where a large part of the population of Russia, hot pressurized underground water are rare. Therefore, in the near future we can expect only the use of heat pumps, which are able to directly use the heat of the earth.

Opportunities to build geothermal power plants, except in Kamchatka and the Kuril Islands, there are in the Urals, in the Krasnodar Territory, Stavropol. The possibilities of construction of geothermal power plant in the southern regions of Western Siberia. «But in general, should be energy strategy by region, comprehensive approach. If there is an opportunity to build a geothermal power plant — to be built: it’s cheap energy, and the lack of demand in hydrocarbons,» — said Kolesnikov.

Alex Kiryukhin sure that geothermal energy can be produced everywhere — the question is quantity and quality. But, of course, for hydrothermal power the main limiting factor will long serve as strong attachment to heat sources.

Even if the savings in geothermal power will be less than expected, the gain for the environment is evident. Valentine Svalova Institute of Geoscience in «Geothermal Resources of Russia and the integrated use» showed that if by geothermal energy production will be achieved in 7800 GWh of electricity, it would save 15.4 million barrels of oil, eliminate emissions of approximately 7 million tons of CO2.

Sustainability and cheapness make geothermal compelling. «Although geothermal power plants have a low potential, give less power, they do not require the use of hydrocarbons, — repeats Kolesnikov. — The situation with oil is clear, the price will only go up, so we want or do not want, and geothermal energy will develop.»

The total capacity of geothermal power plants

Tatiana Krupina