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The presentation is an additional material for the lessons on the development of energy. Energy of any country is the basis of development productive forces, creating the material and technical base of society. The presentation reflects the problems and prospects of all types of energy, promising (new) types of energy, using the experience of museum pedagogy, independent research work of students (work with the Japan Today magazine), creative work of students (posters). The presentation can be used in geography lessons in grades 9 and 10, in extracurricular activities (classes in electives, elective courses), in conducting Geography Week "April 22 - Earth Day", in ecology and biology lessons "Global problems of mankind. Raw material and energy problem”.
In my work, I used the method of problem-based learning, which consisted in creating problem situations for students and resolving them in the process of joint activities of students and teachers. At the same time, the maximum independence of students was taken into account and under the general guidance of a teacher who directs the activities of students.
Problem-based learning allows not only to form in students the necessary system of knowledge, skills and abilities, to achieve a high level of development of schoolchildren, but, most importantly, it allows you to form a special style of mental activity, research activity and independence of students. When working with this presentation, students show an actual direction - the research activity of schoolchildren.
The industry unites a group of industries engaged in the extraction and transportation of fuel, energy generation and its transfer to the consumer.
Natural resources that are used to generate energy are fuel resources, hydro resources, nuclear energy, as well as alternative forms of energy. The location of most industries depends on the development of electricity. Our country has huge reserves of fuel and energy resources. Russia was, is and will be one of the world's leading energy powers. And this is not only because in the bowels of the country there are 12% of the world's coal reserves, 13% of oil and 36% of the world's reserves. natural gas, which is sufficient to fully meet their own needs and for export to neighboring countries. Russia has become one of the world's leading energy powers, primarily due to the creation of a unique production, scientific, technical and human potential of the fuel and energy complex.
Raw material problem
Mineral resources- the primary source, the initial basis of human civilization in almost all phases of its development:
– Fuel minerals;
– Ore minerals;
- Non-metallic minerals.
Today's energy consumption is growing exponentially. Even if we take into account that the growth rate of electricity consumption will decrease somewhat due to the improvement of energy-saving technologies, the reserves of electrical raw materials will last for a maximum of 100 years. However, the situation is aggravated by the discrepancy between the structure of stocks and consumption of organic raw materials. Thus, 80% of fossil fuel reserves are coal and only 20% are oil and gas, while 8/10 of modern energy consumption is oil and gas.
Consequently, the time frame is even narrower. However, only today humanity is getting rid of ideological ideas that they are practically endless. Mineral resources are limited, virtually irreplaceable.
Energy problem.
Today, the energy of the world is based on energy sources:
– Combustible minerals;
– Combustible organic fossils;
- The energy of rivers. Non-traditional types of energy;
- The energy of the atom.
With the current rate of increase in the cost of the Earth's fuel resources, the problem of using renewable energy sources is becoming increasingly relevant and characterizes the energy and economic independence of the state.
Advantages and disadvantages of TPP.
TPP advantages:
1. The cost of electricity at hydroelectric power plants is very low;
2. HPP generators can be turned on and off quickly enough depending on energy consumption;
3. No air pollution.
Disadvantages of TPP:
1. Construction of a hydroelectric power station can be longer and more expensive than other energy sources;
2. Reservoirs can cover large areas;
3. Dams can harm fisheries by blocking the way to spawning grounds.
Advantages and disadvantages of HPP.
Advantages of HPP:
– Built quickly and cheaply;
– Work in a constant mode;
– Placed almost everywhere;
– The predominance of thermal power plants in the energy sector of the Russian Federation.
Disadvantages of HPP:
– Consume a large number of fuel;
– Requires a long stop during repairs;
– A lot of heat is lost in the atmosphere, a lot of solid and harmful gases are emitted into the atmosphere;
– major pollutants environment.
In the structure of electricity generation in the world, the first place belongs to thermal power plants (TPPs) - their share is 62%.
An alternative to fossil fuels and a renewable energy source is hydropower. Hydroelectric power plant (HPP)- a power plant that uses the energy of a water stream as an energy source. Hydroelectric power plants are usually built on rivers by constructing dams and reservoirs. Hydropower is the generation of electricity through the use of renewable river, tidal, geothermal water resources. This use of renewable water resources involves managing floods, strengthening riverbeds, transferring water resources to areas suffering from drought, and conserving groundwater flows.
However, even here the energy source is quite limited. This is due to the fact that large rivers, as a rule, are far from industrial centers or their capacities are almost completely used. Thus, hydropower, which currently provides about 10% of the world's energy production, will not be able to significantly increase this figure.
Problems and prospects of nuclear power plants
In Russia, the share atomic energy reaches 12%. The reserves of mined uranium in Russia have an electrical potential of 15 trillion. kWh, this is as much as all our power plants can produce in 35 years. Today, only nuclear power
capable of sharp and short term reduce the greenhouse effect. The current problem is the safety of nuclear power plants. The year 2000 was the beginning of the transition to fundamentally new approaches to standardization and ensuring the radiation safety of nuclear power plants.
Over 40 years of development nuclear energy in the world, about 400 power units have been built in 26 countries of the world. The main advantages of nuclear energy are high final profitability and the absence of emissions of combustion products into the atmosphere, the main disadvantages are the potential danger of radioactive contamination of the environment by fission products of nuclear fuel during an accident and the problem of processing used nuclear fuel.
Unconventional (alternative energy)
1. Solar energy. This is the use of solar radiation to obtain energy in any form. Solar energy uses a renewable energy source and may become environmentally friendly in the future.
Advantages solar energy:
– Public availability and inexhaustibility of the source;
– Theoretically, complete safety for the environment.
Disadvantages of solar energy:
– The flow of solar energy on the Earth's surface is highly dependent on latitude and climate;
- The solar power plant does not work at night and does not work efficiently enough in the morning and evening twilight;
Photovoltaic cells contain poisonous substances such as lead, cadmium, gallium, arsenic, etc., and their production consumes a lot of other hazardous substances.
2. Wind power. It is an energy industry specializing in the use of wind energy - kinetic energy air masses in the atmosphere. Since wind energy is a consequence of the activity of the sun, it is classified as a renewable energy.
Prospects for wind energy.
Wind power is a booming industry, and at the end of 2007 the total installed capacity of all wind turbines was 94.1 gigawatts, a five-fold increase since 2000. Wind farms around the world produced about 200 billion kWh in 2007, which is about 1.3% of the world's electricity consumption. Coastal wind farm Middelgrunden, near Copenhagen, Denmark. At the time of construction, it was the largest in the world.
Opportunities for the implementation of wind energy in Russia. In Russia, the possibilities of wind energy to date remain practically unrealized. A conservative attitude towards the future development of the fuel and energy complex practically hinders the effective introduction of wind energy, especially in the Northern regions of Russia, as well as in the steppe zone of the Southern Federal District, and in particular in the Volgograd region.
3. Thermonuclear energy. The sun is a natural thermonuclear reactor. Even more interesting, albeit a relatively distant prospect, is the use of nuclear fusion energy. Thermonuclear reactors, according to calculations, will consume less fuel per unit of energy, and both this fuel itself (deuterium, lithium, helium-3) and their synthesis products are non-radioactive and, therefore, environmentally safe.
Prospects for thermonuclear energy. This area of energy has a huge potential, currently, within the framework of the "ITER" project, which involves Europe, China, Russia, the USA, South Korea and Japan, France is building the largest thermonuclear reactor, the purpose of which is to bring out the CNF (Controlled Thermonuclear Fusion) to a new level. Construction is planned to be completed in 2010.
4. Biofuel, biogas. Biofuel is a fuel from biological raw materials, obtained, as a rule, as a result of the processing of sugar cane stalks or seeds of rapeseed, corn, soybeans. A distinction is made between liquid biofuels (for internal combustion engines, for example, ethanol, methanol, biodiesel) and gaseous (biogas, hydrogen).
Types of biofuels:
– Biomethanol
– Bioethanol
– Biobutanol
– Dimethyl ether
– Biodiesel
– Biogas
– Hydrogen
On this moment the most developed are biodiesel and hydrogen.
5. Geothermal energy. Hidden beneath Japan's volcanic islands is vast amounts of geothermal energy that can be harnessed by extracting hot water and steam. Benefit: Emits about 20 times less carbon dioxide when generating electricity, reducing its impact on the global environment.
6. The energy of waves, ebbs and flows. In Japan, the most important source of energy is wave turbines, which convert the vertical movement of ocean waves into air pressure that rotates the turbines of electric generators. On the coast of Japan, a large number of buoys have been installed that use the energy of the ebbs and flows. This is how ocean energy is used to ensure the safety of ocean transport.
The huge potential of solar energy could theoretically provide all the world's energy needs. But the efficiency of converting heat into electricity is only 10%. This limits the possibilities of solar energy. Fundamental difficulties also arise when analyzing the possibilities of creating high-power generators using wind energy, ebbs and flows, geothermal energy, biogas, vegetable fuel, etc. All this leads to the conclusion that the possibilities of the considered so-called "reproducible" and relatively environmentally friendly energy resources are limited, at least in the relatively near future. Although the effect of their use in solving individual problems of energy supply can already be quite impressive.
Of course, there is optimism about the possibilities of thermonuclear energy and other efficient ways of obtaining energy, intensively studied by science, but at the current scale of energy production. With the practical development of these possible sources, it will take several decades due to the high capital intensity and the corresponding inertia in the implementation of projects.
Research work of students:
1. Special report "Green Energy" for the future: “Japan is the world leader in the production of solar electricity. 90% of the solar energy produced in Japan is generated solar panels in ordinary houses. The Japanese government has set a goal in 2010 to receive approximately 4.8 million kilowatts of energy from solar panels. Biomass electricity production in Japan. Methane gas is emitted from kitchen waste. This gas runs an engine that generates electricity, and favorable conditions are also created to protect the environment.
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1. Prospects for the development of thermal power engineering
Mankind satisfies about 80% of its energy needs with fossil fuels: oil, coal, natural gas. Their share in the balance of the electric power industry is somewhat lower - about 65% (39% - coal, 16% - natural gas, 9% - liquid fuels).
According to the forecasts of the International Energy Agency, by 2020, with an increase in the consumption of primary energy carriers by 35%, the share of fossil fuels will increase to more than 90%.
Today, the demand for oil and natural gas is provided for 50-70 years. However, despite the constant growth in production, these periods have not decreased over the past 20-30 years, but have been growing as a result of the discovery of new deposits and the improvement of production technologies. As for coal, its recoverable reserves will last more than 200 years.
Thus, there is no question of a shortage of fossil fuels. The point is to make the most rational use of them to increase standard of living people while unconditionally preserving their habitat. This fully applies to the electric power industry.
In our country, the main fuel for thermal power plants is natural gas. In the foreseeable future, its share will apparently decrease, however, the absolute consumption by power plants will remain approximately constant and quite large. For many reasons - not always reasonable - it is not used effectively enough.
Natural gas consumers are traditional steam turbine thermal power plants and thermal power plants, mainly with a steam pressure of 13 and 24 MPa (their efficiency in condensing mode is 36-41%), but also old thermal power plants with significantly lower parameters and high production costs.
It is possible to significantly increase the efficiency of gas use by using gas turbine and combined cycle technologies.
The maximum unit power of the gas turbine has reached to date 300 MW, the efficiency in autonomous operation is 36-38%, and in multi-shaft gas turbines, created on the basis of aircraft engines with high pressure ratios, it is 40% or more, the initial gas temperature is 1300-1500 ° C, compression ratio - 20-30.
To ensure the practical success of reliability, thermal efficiency, low specific cost and operating costs, today power gas turbines are designed according to the simplest cycle, for the maximum achievable gas temperature (it is constantly growing), with pressure rise rates close to optimal in terms of specific work and efficiency of combined plants , which use the heat of exhaust gases in the turbine. The compressor and turbine are located on the same shaft. Turbo-machines form a compact unit with a built-in combustion chamber: annular or block-annular. The zone of high temperatures and pressure is localized in a small space, the number of details that perceive them is small, and these details themselves are carefully worked out. These principles are the result of years of design evolution.
Most of the gas turbines with a capacity of less than 25-30 MW were created on the basis of or according to the type of aircraft or ship gas turbine engines(GTE), which are characterized by the absence of horizontal splits and the assembly of housings and rotors using vertical splits, the widespread use of rolling bearings, small weight and dimensions. The service life and readiness indicators required for ground application and operation at power plants are provided in aircraft structures at acceptable costs.
With a power of more than 50 MW, the GTP is designed specifically for power plants, and is performed as single-shaft, with moderate compression ratios and sufficient high temperature exhaust gases, facilitating the use of their heat. To reduce the size and cost and increase efficiency, GTPs with a capacity of 50-80 MW are made high-speed with an electric generator driven through a gearbox. Typically, such gas turbines are aerodynamically and structurally similar to more powerful units made for the direct drive of electric generators with a speed of 3600 and 3000 rpm. Such simulation increases reliability and reduces development and development costs.
Cycle air is the main coolant in GTU. Air cooling systems are implemented in nozzle and rotor blades, using technologies that provide the required properties at an acceptable cost. The use of steam or water for cooling turbines can improve the performance of gas turbines and steam turbines with the same cycle parameters or provide a further increase in the initial temperature of gases compared to air. Although technical background for the use of cooling systems with these coolants are far from being developed in such detail as with air, their implementation becomes a practical issue.
GTP mastered "low-toxic" combustion of natural gas. It is most effective in combustion chambers operating on a previously prepared homogeneous mixture of gas with air at large (a = 2-2.1) air excesses and with a uniform and relatively low (1500-1550 ° C) flame temperature. With such an organization of combustion, NOX formation can be limited to 20-50 mg/m3 under normal conditions (standardly they refer to combustion products containing 15% oxygen) at high combustion efficiency (CO concentration<50 мг/м3). Проблема заключается в сохранении устойчивости горения и близких к оптимальным условий горения при изменениях режимов. С разной эффективностью это достигается ступенчатой подачей топлива (включением/отключением тех или иных горелок или зон горения), регулированием расхода поступающего на горение воздуха и дежурным диффузионным факелом небольшой мощности.
It is much more difficult to reproduce a similar technology of "low-toxic" combustion on liquid fuels. However, there are some successes here too.
Of great importance for the progress of stationary gas turbines is the choice of materials and shaping technologies that ensure long service life, reliability and moderate cost of their parts.
Turbine and combustion chamber parts, which are washed by high-temperature gases containing components that can cause oxidation or corrosion, and experience high mechanical and thermal loads, are made of nickel-based complex alloys. The blades are intensively cooled and are made with complex internal paths using the precision casting method, which allows the use of materials and obtaining shapes of parts that are impossible with other technologies. In recent years, casting of blades with directional and single crystallization has been increasingly used, which makes it possible to significantly improve their mechanical properties.
The surfaces of the hottest parts are protected by coatings that prevent corrosion and lower the temperature of the base metal.
The simplicity and small size of even powerful gas turbines and their ancillary equipment make it technically possible to supply them in large, factory-made units with auxiliary equipment, piping and cable connections, tested and adjusted for normal operation. When installed outdoors, an element of each unit is a casing (casing) that protects the equipment from bad weather and reduces sound emissions. Blocks are installed on flat foundations and docked. The space under the skin is ventilated.
The Russian electric power industry has many years, although not unambiguous, experience in the operation of gas turbines with a unit capacity of 2.5 to 100 MW. A good example is the gas turbine CHP plant, which has been operating for more than 25 years in the harsh climatic conditions of Yakutsk, in an isolated power system with an uneven load.
Currently, Russian power plants operate gas turbines, which, in terms of their parameters and indicators, are noticeably inferior to foreign ones. To create modern power gas turbines, it is advisable to combine the efforts of power engineering and aircraft engine enterprises on the basis of aviation technology.
A power gas turbine with a capacity of 110 MW has already been manufactured and is being tested, produced by the defense enterprises Mash-proekt (Nikolaev, Ukraine) and Saturn (Rybinsk Motors), which has quite modern performance.
Various standard sizes of gas turbines of medium power have been created in the country on the basis of aircraft or marine engines. Several units GTD-16 and GTD-25 of Mashinproekt, GTU-12 and GTU-16P of the Perm Aviadvigatel, AL-31ST Saturn and NK-36 Dvigateli NK are operated with operating time of 15-25 thousand hours per compressor stations of main gas pipelines. For many years, hundreds of earlier gas turbines operated by Trud (now Dvigateli NK) and Mashproekt have been operated there. There is a rich and, in general, positive experience of operation at the power plants of the Mashproekt GTU with a capacity of 12 MW, which served as the basis for more powerful PT-15s.
In modern power gas turbines of high power, the temperature of the exhaust gases in the turbine is 550-640 °C. Their heat can be used for heat supply or utilized in the steam cycle, with an increase in the efficiency of the combined steam and gas plant up to 55-58%, actually obtained at the present time. Various combinations of gas turbine and steam turbine cycles are possible and practically used. Among them, binary ones dominate, with the supply of all heat in the combustion chamber of the gas turbine, the production of steam of high parameters in the waste heat boiler behind the gas turbine and its use in the steam turbine.
At the North-Western CHPP of St. Petersburg, for about 2 years, the first binary type STP in our country has been operated. Its power is 450 MW. The CCGT includes two V94.2 gas turbines developed by Siemens, supplied by its joint venture Interturbo with LMZ, 2 waste heat boilers and one steam turbine. The supply of a block automated process control system for a CCGT was carried out by a consortium of Western firms. All other main and auxiliary equipment was supplied by domestic enterprises.
By September 1, 2002, the CCGT operated 7200 hours in the condensing mode when operating in the control range (300-450 MW) with an average efficiency of 48-49%; its estimated efficiency is 51%.
In a similar CCGT with the domestic GTE-110, it is possible to obtain even a slightly higher efficiency.
Even higher efficiency, as can be seen from the same table, will ensure the use of the currently designed GTE-180.
With the use of currently designed gas turbines, it is possible to achieve significantly higher performance, not only in new construction, but also in the technical re-equipment of existing thermal power plants. It is important that with technical re-equipment with the preservation of the infrastructure and a significant part of the equipment and the implementation of binary CCGT units on them, it is possible to achieve close to optimal efficiency values with a significant increase in the power of power plants.
The amount of steam that can be generated in the waste heat boiler installed behind the GTE-180 is close to the capacity of one exhaust of the K-300 steam turbine. Depending on the number of exhaust gases stored during those re-equipment, it is possible to use 1.2 or 3 GTE-180. To avoid exhaust overload at low outdoor temperatures, it is advisable to use a three-loop scheme of the steam section with steam reheating, in which a large CCGT power is achieved with a lower steam flow to the condenser.
While maintaining all three emissions, the CCGT with a capacity of about 800 MW is located in a cell of two neighboring power units: one steam turbine remains, and the other is dismantled.
The unit cost of those re-equipment according to the CCGT cycle will be 1.5 or more times cheaper than new construction.
Similar solutions are expedient for those re-equipment of gas-fired power plants with power units of 150 and 200 MW. They can be widely used less powerful GTE-110.
For economic reasons, first of all, thermal power plants need technical re-equipment. The most attractive for them are binary CCGTs of the type at the North-Western CHPP of St. Petersburg, which make it possible to sharply increase the generation of electricity on heat consumption and change the ratio between electrical and thermal loads over a wide range, while maintaining an overall high fuel utilization factor. The module worked out at Severo-Zapadnaya CHPP: GTU - a waste heat boiler generating 240 t/h of steam, can be directly used to feed turbines PT-60, PT-80 and T-100.
When their exhausts are fully loaded, the mass flow rate of steam through the first stages of these turbines will be much lower than the nominal one and it will be possible to pass it at the reduced pressures characteristic of CCGT-450. This, as well as lowering the temperature of live steam to less than 500-510 ° C, will remove the issue of exhaustion of the resource of these turbines. Although this will be accompanied by a reduction in the power of steam turbines, the total power of the unit will increase by more than 2 times, and its efficiency in terms of power generation will be significantly higher, regardless of the mode (heat supply), than that of the best condensing power units.
Such a change in indicators radically affects the efficiency of CHP. The total costs for the generation of electricity and heat will decrease, and the competitiveness of CHPPs in the markets of both types of products - as evidenced by financial and economic calculations - will increase.
At power plants, in the fuel balance of which there is a large proportion of fuel oil or coal, but there is also natural gas, in an amount sufficient to feed the gas turbine, thermodynamically less efficient gas turbine superstructures may be appropriate.
For the domestic thermal power industry, the most important economic task is the development and widespread use of gas turbine plants with the parameters and indicators that have already been achieved in the world. The most important scientific task is to ensure the design, manufacture and successful operation of these gas turbines.
Of course, there are still many opportunities for further development of gas turbines and combined cycle plants and improving their performance. CCGT units with an efficiency of 60% have been designed abroad, and the task is to increase it to 61.5-62% in the foreseeable future. To do this, instead of cycling air, the gas turbine uses water vapor as a coolant and closer integration of the gas turbine and steam cycles is carried out.
Even greater opportunities are opened by the creation of "hybrid" installations, in which gas turbines (or CCGTs) are built on top of a fuel cell.
High-temperature fuel cells (FC), solid oxide or based on molten carbonates, operating at temperatures of 850 and 650 °C, serve as heat sources for the gas turbine and steam cycle. In specific projects with a capacity of about 20 MW - mainly in the USA - calculated efficiencies of 70% have been obtained.
These units are designed to run on natural gas with internal reforming. It is possible, of course, that they operate on synthesis gas or pure hydrogen obtained from coal gasification, and the creation of complexes in which coal processing is integrated into the technological cycle.
The existing programs set the task of increasing the capacity of hybrid plants to 300 MW or more in the future, and their efficiency - up to 75% on natural gas and 60% on coal.
The second most important fuel for energy is coal. In Russia, the most productive coal deposits - Kuznetsk and Kansko-Achinsk - are located in the south of central Siberia. The coals of these deposits are low-sulphurous. The cost of their extraction is low. However, their area of application is currently limited due to the high cost of rail transport. In the European part of Russia, in the Urals and the Far East, transportation costs exceed the cost of extracting Kuznetsk coal by 1.5-2.5 times, and Kansk-Achinsk - by 5.5-7.0 times.
In the European part of Russia, coal is mined by the mine method. Basically, these are hard coals from the Pechora, anthracites from the Southern Donbass (power engineers get their screenings - fines) and brown coals from the Moscow region. All of them are high-ash and sulphurous. Due to natural conditions (geological or climatic), the cost of their production is high, and it is difficult to ensure competitiveness when used at power plants, especially with the inevitable tightening of environmental requirements and the development of the market for thermal coals in Russia.
Currently, thermal power plants use coals that vary greatly in quality: more than 25% of their total consumption has an ash content above 40%; 18.8% - calorific value below 3000 kcal/kg; 6.8 million tons of coal - sulfur content over 3.0%. The total amount of ballast in coal is 55 million tons per year, including rocks - 27.9 million tons and moisture - 27.1 million tons. As a result, it is very important to improve the quality of thermal coals.
The prospect of using coal in the Russian electric power industry will be determined by the state policy of prices for natural gas and coal. In recent years, there has been an absurd situation when gas in many regions of Russia is cheaper than coal. It can be assumed that gas prices will rise faster and become higher than coal prices in a few years.
To expand the use of Kuznetsk and Kansk-Achinsk coals, it is advisable to create favorable conditions for their rail transportation and develop alternative methods of transporting coal: by water, pipelines, in an enriched state, etc.
For strategic reasons, in the European part of Russia it is necessary to maintain the extraction of some amount of thermal coal of the best quality and in the most productive mines, even if this requires state subsidies.
The use of coal in power plants in traditional steam power units is commercially viable today and will be viable for the foreseeable future. gas turbine electric power industry russia coal
In Russia, coal is burned at condensing power plants equipped with power units of 150, 200, 300, 500 and 800 MW, and at thermal power plants with boilers with a capacity of up to 1000 t/h.
Despite the low quality of coals and the instability of their characteristics during delivery, high technical, economic and operational indicators were achieved at domestic coal blocks shortly after their development.
Large boilers use coal dust flaring, mainly with solid ash removal. Mechanical underburning does not exceed, as a rule, 1-1.5% when burning hard coal and 0.5% - brown coal. It increases to q4<4% при использовании низко реакционных тощих углей и антрацитового штыба в котлах с жидким шлакоудалением. Расчетные значения КПД брутто пылеугольных котлов составляют 90-92,5%. При длительной эксплуатации они на 1-2% ниже из-за увеличенных присосов воздуха в газовый тракт, загрязнения и шлакования поверхностей нагрева, ухудшения качества угля. Имеются реальные возможности значительного улучшения КПД котлов.
In recent years, coal blocks have been operating in a variable mode with deep unloading or overnight shutdowns. High, close to the nominal efficiency is maintained on them when unloaded to N3JI=0.4-=-0.5 NH0M.
Worse is the situation with the protection of the environment. At Russian coal-fired thermal power plants there are no operating flue gas desulfurization systems, no catalytic systems for their purification from NOX. The electrostatic precipitators installed for ash collection are not efficient enough; on boilers with a capacity of up to 640 t / h, various even less efficient cyclones and wet apparatuses are widely used.
Meanwhile, for the future of thermal energy, its harmonization with the environment is of paramount importance. It is most difficult to achieve it when using coal as a fuel, which contains a non-combustible mineral part and organic compounds of sulfur, nitrogen and other elements that form substances harmful to nature, people or buildings after combustion of coal.
At the local and regional levels, the main air pollutants whose emissions are regulated are gaseous oxides of sulfur and nitrogen and particulate matter (ash). Their limitation requires special attention and costs.
One way or another, emissions of volatile organic compounds (the most severe pollutants, in particular benzopyrene), heavy metals (for example, mercury, vanadium, nickel) and polluted effluents into water bodies are also controlled.
When rationing emissions from thermal power plants, the state limits them to a level that does not cause irreversible changes in the environment or human health that can adversely affect the living conditions of current and future generations. The definition of this level is associated with many uncertainties and depends to a large extent on technical and economic possibilities, since unreasonably stringent requirements can lead to increased costs and worsen the economic situation of the country.
With the development of technology and the strengthening of the economy, the possibilities for reducing emissions from thermal power plants are expanding. Therefore, it is legitimate to speak (and strive!) for the minimum technically and economically conceivable impact of TPPs on the environment and to go for increased costs, however, such that the competitiveness of TPPs is still ensured. Something similar is being done now in many developed countries.
Let us return, however, to traditional coal thermal power plants.
Of course, relatively inexpensive, mastered and efficient electric and fabric filters for radical dedusting of flue gases emitted into the atmosphere should be used first of all. Difficulties with electrostatic precipitators typical for the Russian power industry can be eliminated by optimizing their size and design, improving power systems using pre-ionization and AC, intermittent or pulsed power supplies, and automating filter operation control. In many cases, it is advisable to reduce the temperature of the gases entering the electrostatic precipitator.
To reduce emissions of nitrogen oxides into the atmosphere, primarily technological measures are used. They consist in influencing the combustion process by changing the design and operating modes of burners and furnace devices and creating conditions under which the formation of nitrogen oxides is small or impossible.
In boilers operating on Kansk-Achinsk coal, it is advisable to use the proven principle of low-temperature combustion to reduce the formation of nitrogen oxides. With three stages of fuel supply, the coefficient of excess air in the zone of active combustion will be 1.0-1.05. An excess of oxidizing agent in this zone, in the presence of intensive mass transfer in the volume, will provide a low rate of slagging. So that the removal of part of the air from the active combustion zone does not increase the temperature of the gases in its volume, a replacement amount of recirculation gases is supplied to the torch. With such an organization of combustion, it is possible to reduce the concentration of nitrogen oxides to 200-250 mg/m3 at the rated load of the power unit.
To reduce nitrogen oxide emissions, SibVTI is developing a coal dust pre-burning pre-combustion system that will reduce NOx emissions to less than 200 mg/m3.
When Kuznetsk coal is used on 300-500 MW units, low-toxic burners and staged combustion of fuel should be used to reduce the formation of NOX. The combination of these activities can provide NOX emissions<350 мг/м3.
It is especially difficult to reduce the formation of NOX during the combustion of low-reactivity fuel (ash and Kuznetsk lean) in boilers with liquid ash removal. At present, NOX concentrations on such boilers are 1200-1500 mg/m3. If natural gas is available at power plants, it is advisable to organize three-stage combustion with NOX reduction in the upper part of the furnace (reburning process). In this case, the main burners are operated with an excess air coefficient agor = 1.0-1.1, and natural gas is fed into the furnace together with a drying agent to create a reduction zone. Such a combustion scheme can provide NOX concentrations up to 500-700 mg/m3.
Chemical methods are used to clean flue gases from nitrogen oxides. There are two nitrogen treatment technologies used industrially: selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) of nitrogen oxides.
With a higher efficiency of SCR technology, the specific capital costs in it are an order of magnitude higher than in SNCR. On the contrary, the consumption of the reducing agent, most often ammonia, is 2-3 times lower in SCR technology due to the higher selectivity of ammonia use compared to SNCR.
The SNCR technology, tested on a boiler with a capacity of 420 t/h at the Togliatti CHPP, can be used in the technical re-equipment of coal-fired power plants with boilers operating with liquid ash removal. This will provide them with the level of NOX emissions = 300-350 mg/m3. In environmentally stressed areas, SCR technology can be used to achieve NOX emissions of around 200 mg/m3. In all cases, the use of nitrogen scrubbers should be preceded by technological measures to reduce the formation of NOX.
With the help of currently mastered technologies, economically acceptable purification of the products of combustion of sour fuel with capture of 95-97% SO2 is possible. In this case, natural limestone is usually used as a sorbent; commercial gypsum is a by-product of purification.
In our country, at the Dorogobuzhskaya GRES, an installation with a capacity of 500-103 nm3 / h was developed and commercially operated, implementing the ammonia-sulphate desulfurization technology, in which ammonia is the sorbent, and commercial ammonium sulfate, which is a valuable fertilizer, is a by-product.
Under the standards in force in Russia, the binding of 90-95% SO2 is necessary when using fuel with a reduced sulfur content S > 0.15% kg/MJ. When burning low and medium sulfur fuels S< 0,05% кг/МДж целесообразно использовать менее капиталоемкие технологии.
The following are currently considered as the main directions for further improving the efficiency of coal-fired thermal power plants:
increase in steam parameters in comparison with the mastered24 MPa, 540/540 °С with simultaneous improvement of equipment and systems of steam power plants;
development and improvement of promising coal-fired CCGTs;
improvement and development of new flue gas cleaning systems.
Comprehensive improvement of schemes and equipment made it possible to increase the efficiency of supercritical coal-fired power units from about 40 to 43-43.5% without changing the steam parameters. Increasing the parameters from 24 MPa, 545/540 °C to 29 MPa, 600/620 °C increases the efficiency in real projects on coal up to about 47%. The increase in the cost of power plants with large (600-800 MW) units due to the use of more expensive materials at higher parameters (for example, austenitic tubes of superheaters) is relatively small. It is 2.5% with an increase in efficiency from 43 to 45% and 5.5 - to 47%. However, even such a rise in price pays off at very high coal prices.
Work on super-critical steam parameters, begun in the middle of the last century in the USA and the USSR, has found industrial implementation in Japan and Western European countries with high energy prices in recent years.
In Denmark and Japan, power units with a capacity of 380-1050 MW with a live steam pressure of 24-30 MPa and superheating up to 580-610 °C have been built and successfully operated on coal. Among them there are blocks with double reheating up to 580 °C. The efficiency of the best Japanese blocks is at the level of 45-46%, the Danish ones, operating on cold circulating water with deep vacuum, are 2-3% higher.
In Germany, lignite power units with a capacity of 800-1000 MW were built with steam parameters up to 27 MPa, 580/600 °C and efficiency up to 45%.
Works on a power unit with super critical steam parameters (30 MPa, 600/600 °C), organized in our country, have confirmed the reality of creating such a unit with a capacity of 300-525 MW with an efficiency of about 46% in the coming years.
The increase in efficiency is achieved not only due to an increase in steam parameters (their contribution is about 5%), but also - to a greater extent - due to an increase in the efficiency of the turbine (4.5%) and boiler (2.5%) and the improvement of station equipment with a decrease in losses characteristic of his work.
The backlog available in our country was focused on a steam temperature of 650 ° C and the widespread use of austenitic steels. A small experimental boiler with such parameters and a steam pressure of 30.0 MPa has been operating since 1949 at the VTI experimental CHPP for more than 200 thousand hours. It is in working order and can be used for research purposes and long-term tests. Power unit SKR-100 at Kashirskaya GRES with a boiler with a capacity of 720 t/h and a turbine for 30 MPa/650 °С
worked in 1969 over 30 thousand hours. After the termination of operation for reasons not related to its equipment, it was mothballed. In 1955, K. Rakov at VTI worked out the possibilities of creating a boiler with steam parameters of 30 MPa/700 °C.
The use of austenitic steels with high coefficients of linear expansion and low thermal conductivity for the manufacture of massive non-heated parts: steam pipelines, rotors and turbine casings and fittings causes obvious difficulties under the inevitable cyclic loads for power equipment. With this in mind, nickel-based alloys capable of operating at significantly higher temperatures may be more suitable in practice.
So in the USA, where, after a long break, work has been resumed aimed at introducing super-critical steam parameters, they are mainly concentrating on the development and testing of the materials necessary for this.
For parts operating at the highest pressures and temperatures: superheater pipes, headers, main steam lines, several nickel-based alloys were selected. For the reheat path, where pressures are significantly lower, austenitic steels are also considered, and for temperatures below 650 °C, promising ferritic steels are considered.
During 2003, it is planned to identify improved alloys, manufacturing processes and coating methods that ensure the operation of power boilers at steam temperatures up to 760 ° C, taking into account characteristic alignments, temperature changes and possible corrosion in the environment of real coal combustion products.
It is also planned to correct the ASME calculation standards for new materials and processes and consider the design and operation of equipment at steam temperatures up to 870 ° C and pressure up to 35 MPa.
In the countries of the European Union, on the basis of cooperative financing, an improved pulverized-coal power unit with a maximum steam temperature above 700 °C is being developed with the participation of a large group of energy and machine-building companies. For it, the parameters of fresh steam are taken
37.5 MPa/700 °С and double reheat cycle up to 720 °С at pressures of 12 and 2.35 MPa. With a pressure in the condenser of 1.5-2.1 kPa, the efficiency of such a unit should be above 50% and can reach 53-54%. And here the materials are critical. They are designed to provide a long-term strength over 100 thousand hours equal to 100 MPa at temperatures:
nickel-based alloys for pipes of the last bundles of superheaters, outlet manifolds, steam pipelines, turbine casings and rotors - 750 °C;
austenitic steels for superheaters - 700 °C;
ferritic-martensitic steels for boiler pipes and collectors - 650 °C.
New boiler and turbine designs, manufacturing techniques (such as welding) and new tight layouts are being developed to reduce the need for the most expensive materials and the unit cost of units without compromising the reliability and performance characteristics of modern steam power units.
Implementation of the block is scheduled after 2010, and the ultimate goal in another 20 years is to achieve a net efficiency of up to 55% at steam temperatures up to 800 °C.
Despite the successes already achieved and the prospects for further improvement of steam power units, the thermodynamic benefits of combined plants are so great that much attention is paid to the development of coal-fired CCGT.
Since the combustion of ash-containing fuel in gas turbines is difficult due to the formation of deposits in the flow path of turbines and corrosion of their parts, work on the use of coal in gas turbines is carried out mainly in two directions:
gasification under pressure, purification of combustible gas and its combustion in gas turbines; the gasification unit is integrated with the CCGT, the cycle and scheme of which remain the same as for natural gas;
direct combustion of coal under pressure in a high-pressure fluidized bed steam generator, purification and expansion of combustion products in a gas turbine.
The implementation of the processes of gasification and purification of artificial gas from coal ash and sulfur compounds at high pressures makes it possible to increase their intensity, reduce the size and cost of equipment. The heat removed during gasification is utilized within the CCGT cycle, and the steam and water used in gasification, and sometimes air, are also taken from it. Losses arising from coal gasification and generator gas purification reduce the CCGT efficiency. Nevertheless, with rational design, it can be quite high.
The technologies of coal gasification in a bulk bed, in a fluidized bed and in a stream are the most developed and practically applied. Oxygen is used as an oxidizing agent, less often air. The use of industrially developed technologies for cleaning synthesis gas from sulfur compounds requires cooling the gas to 40 °C, which is accompanied by additional pressure and performance losses. The cost of gas cooling and purification systems is 15-20% of the total cost of TPPs. Now high-temperature (up to 540-600 °C) gas cleaning technologies are being actively developed, which will reduce the cost of systems and simplify their operation, as well as reduce the losses associated with cleaning. Regardless of the gasification technology, 98-99% of coal energy is converted into combustible gas.
In 1987-91. in the USSR, under the state program "Clean Energy", VTI and CKTI, together with design institutes, several CCGTs with coal gasification were worked out in detail.
The unit capacity of the units (net) was 250-650 MW. All three gasification technologies mentioned above were considered in relation to the most common coals: Berezovsky brown, Kuznetsk stone and AS, which are very different in composition and properties. Efficiencies of 39 to 45% and very good environmental performance were obtained. In general, these projects were quite consistent with the then world level. Abroad, similar CCGTs have already been implemented on demonstration samples with a unit capacity of 250-300 MW, and domestic projects were terminated 10 years ago.
Despite this, gasification technologies are of interest to our country. VTI, in particular, continues
experimental work on a gasification plant according to the "hearth" method (with a bulk layer and liquid ash removal) and optimization studies of CCGT schemes.
Given the moderate sulfur content of the most promising domestic coals and the progress made in the economic and environmental performance of traditional pulverized coal power units with which these CCGTs will have to compete, the main rationales for their development are the possibility of achieving higher thermal efficiency and less difficulty in removing CO2 from the cycle. in case it is needed (see below). Bearing in mind the complexity of CCGT with gasification and the high cost of their development and development, it is advisable to take CCGT efficiency at the level of 52-55%, specific cost of 1-1.05 of the cost of a coal block, SO2 and NOX emissions as final goals.< 20 мг/м3 и частиц не более 10 мг/м3. Для достижения их необходимо дальнейшее развитие элементов и систем ПГУ.
By reducing the temperature of the combustible gas at the outlet of the gasifier to 900-1000 °C, purifying it from sulfur compounds and particles and directing it to the gas turbine combustion chamber at an elevated temperature (for example, 500-540 °C at which pipelines and fittings can be made of inexpensive steels ), using air rather than oxygen blast, reducing pressure and heat losses in the gas-air path of the gasification system and using heat exchange circuits closed inside it, it is possible to reduce the loss of efficiency associated with gasification from 16-20 to 10-12% and significantly reduce power consumption by own needs.
Projects carried out abroad also testify to a significant reduction in the unit cost of thermal power plants with CCGT with coal gasification, with an increase in productivity and unit capacity of the equipment, as well as with an increase in the development of technology.
Another possibility is a CCGT unit with combustion of coal in a fluidized bed under pressure. The required air is supplied to the layer by a gas turbine compressor with a pressure of 1-1.5 MPa, the combustion products after cleaning from ash and entrainment expand in the gas turbine and produce useful work. The heat released in the layer and the heat of the gases exhausted in the turbine are used in the steam cycle.
Carrying out the process under pressure, while maintaining all the advantages characteristic of coal combustion in a fluidized bed, makes it possible to significantly increase the unit power of steam generators and reduce their dimensions with more complete combustion of coal and sulfur binding.
The advantages of CCGT with KSD are complete (with an efficiency > 99%) combustion of various types of coal, high heat transfer coefficients and small heating surfaces, low (up to 850 °C) combustion temperatures and, as a result, small (less than 200 mg/m3) NOX emissions, absence of slagging, the possibility of adding sorbent (limestone, dolomite) to the layer and binding 90-95% of sulfur contained in coal in it.
High efficiency (40-42% in condensing mode) is achieved in CCGT with PCR at moderate power (about 100 MWel.) and subcritical steam parameters.
Due to the small size of the boiler and the lack of desulfurization, the area occupied by the CCGT with KSD is small. Block-complete delivery of their equipment and modular construction with a decrease in its cost and terms are possible.
For Russia, CCGTs with KSD are promising, first of all, for the technical re-equipment of coal-fired CHPPs on cramped sites, where it is difficult to locate the necessary environmental equipment. Replacing old boilers with HPG with gas turbines will also significantly improve the efficiency of these CHPPs and increase their electrical capacity by 20%.
At VTI, on the basis of domestic equipment, several standard sizes of CCGT with KSD were developed.
Under favorable economic conditions, such CCGT units could be sold in our country in a short time.
The CCGT technology with KSD is simpler and more familiar to power engineers than gasification plants, which are complex chemical production. Various combinations of both technologies are possible. Their purpose is to simplify gasification and gas purification systems and reduce their characteristic losses, on the one hand, and increase the gas temperature in front of the turbine and gas turbine power in schemes with KSD, on the other hand.
Some reticence of the public and experts and governments reflecting its sentiments in assessing the prospects for widespread and long-term use of coal is associated with growing CO2 emissions into the atmosphere and fears that these emissions can cause global climate change, which will have catastrophic consequences.
A discussion of the validity of these fears (they are not shared by many competent experts) is not the subject of the article.
However, even if they turn out to be correct, in 40-60 years, when it is required, or even earlier, it is quite realistic to create competitive thermal power plants (or energy technology enterprises) operating on coal with negligible CO2 emissions into the atmosphere.
Already today, a significant reduction in CO2 emissions into the atmosphere from thermal power plants, in particular coal-fired ones, is possible with the combined generation of electricity and heat and an increase in the efficiency of thermal power plants.
Using the processes and equipment already mastered, it is possible to design a CCGT with coal gasification, conversion of CO + H2O into H2O and CO2 and removal of CO2 from synthesis gas.
The project used GTU U94.3A from Siemens with an initial gas temperature according to the ISO1190 °C standard, a PRENFLO gasifier (in-line, on dry dust from Pittsburgh No. 8 coal and oxygen blast), a shift reactor and removal of acid gases: H2S, COS and CO2 in Rectizol system from Lurgi.
The advantages of the system are the small size of the equipment when carrying out CO2 removal processes at high (2 MPa) pressure, high partial pressure and CO2 concentration. Removal of about 90% of CO2 is accepted for economic reasons.
The decrease in the efficiency of the original CCGT when removing CO2 occurs due to exergy losses during the exothermic conversion of CO (by 2.5-5%), additional energy losses during the separation of CO2 (by 1%) and due to a decrease in the consumption of combustion products through the gas turbine and boiler utilizer after separation of CO2 (by 1%).
Inclusion in the circuit of devices for CO conversion and removal from the CO2 cycle increases the unit cost of CCGT with GF by 20%. Liquefying the CO2 will add another 20%. The cost of electricity will increase by 20 and 50% respectively.
As mentioned above, domestic and foreign studies indicate the possibility of a further significant - up to 50-53% - increase in the efficiency of CCGT with coal gasification, and, consequently, their modifications with the removal of CO2.
EPRI in the United States promotes the creation of coal-fired energy complexes that are competitive with thermal power plants running on natural gas. It is advisable to build them in stages in order to reduce the initial capital investments and pay them back faster, while at the same time fulfilling the current environmental requirements.
First stage: promising environmentally friendly CCGT with GF.
Second stage: implementation of a CO2 removal and transportation system.
The third stage: the organization of the production of hydrogen or clean transport fuel.
There are much more radical proposals. B considers, for example, a coal-fired thermal power plant with "zero" emissions. Its technological cycle is as follows. The first step is the gasification of the water-coal slurry with the addition of hydrogen and the production of CH4 and H2O. The coal ash is removed from the gasifier, and the gas-vapor mixture is purified.
At the second step, carbon that has passed into the gaseous state, in the form of CO2, is bound by calcium oxide in the reformer, where purified water is also supplied. The hydrogen formed in it is used in the hydrogasification process and fed after fine purification into a solid oxide fuel cell to generate electricity.
In the third step, the CaCO3 formed in the reformer is calcined using the heat released in the fuel cell and the formation of CaO and concentrated CO2 suitable for further processing.
The fourth step is to convert the chemical energy of hydrogen into electricity and heat, which is returned to the cycle.
CO2 is removed from the cycle and mineralized in the processes of carbonization of such minerals as, for example, magnesium silicate, which is ubiquitous in nature in quantities that are orders of magnitude greater than coal reserves. End products of carbonization may be buried in depleted mines.
The efficiency of converting coal into electricity in such a system will be about 70%. With a total cost of CO2 removal of $15-20/tonne, it would increase the cost of electricity by about $0.01/kWh.
The considered technologies are still a matter of the distant future.
Today, the most important measure to ensure sustainable development is economically justified energy saving. In the sphere of production, it is associated with an increase in the efficiency of energy conversion (in our case, at thermal power plants) and the use of synergistic technologies, i.e. combined production of several types of products in one installation, something like energy technology, popular in our country 40-50 years ago. Of course, now it is carried out on a different technical basis.
The first example of such units was CCGT with gasification of oil residues, which are already used on commercial terms. The fuel for them is the waste of oil refineries (for example, coke or asphalt), and the products are electricity, process steam and heat, commercial sulfur and hydrogen used at refineries.
Cogeneration with combined generation of electricity and heat, which is widespread in our country, is essentially an energy-saving synergy technology and deserves much more attention in this capacity than it is currently receiving.
Under the prevailing “market” conditions in the country, the costs of generating electricity and heat at steam turbine CHP plants equipped with outdated equipment and not optimally loaded are in many cases excessively high and do not ensure their competitiveness.
Under no circumstances should this provision be used to revise the fundamentally sound idea of combined heat and power generation. Of course, the issue is not solved by the redistribution of costs between electricity and heat, the principles of which have been fruitlessly discussed in our country for many years. But the economics of CHPPs and heat supply systems in general can be significantly improved by improving technologies (binary gas-fired CCGT, coal-fired CCP, pre-insulated heat pipelines, automation, etc.), organizational and structural changes, and government regulation measures. They are especially needed in a country as cold as ours, with a long heating season.
It is interesting to compare different heat and power technologies with each other. The Russian experience, both digital (pricing) and methodological, does not give grounds for such comparisons, and the attempts made in this direction are not convincing enough. One way or another, we have to attract foreign sources.
Calculations by many organizations, carried out without coordination of initial data, both in our country and abroad, show that without a radical change in the price ratio between natural gas and coal, which has now developed abroad (gas per unit of heat is approximately twice as expensive as coal), modern CCGTs maintain competitive advantages over coal power units. For this position to change, the ratio of these prices must increase to ~4.
An interesting forecast for the development of technologies was made in. It can be seen from it, for example, that the use of fuel oil steam power units is predicted until 2025, and gas - until 2035; the use of CCGT with coal gasification - from 2025, and fuel cells on gas - from 2035; CCGTs running on natural gas will also be used after 2100, CO2 emission will begin after 2025, and at CCGTs with coal gasification after 2055.
With all the uncertainties of such forecasts, they draw attention to the essence of long-term energy problems and possible ways to solve them.
With the development of science and technology, which is taking place in our time, the processes occurring in thermal power plants are becoming more and more intensified and complicated. The approach to their optimization is changing. It is carried out not according to technical ones, as it used to be, but according to economic criteria that reflect market requirements that change and require increased flexibility of thermal power facilities, their ability to adapt to changing conditions. Designing power plants for 30 years of almost unchanged operation is now impossible.
Liberalization and the introduction of market relations in the electric power industry in recent years have caused serious changes in heat and power technologies, ownership structure and methods of financing energy construction. Commercial power plants have emerged, operating on the free electricity market. Approaches to the selection and design of such power plants are very different from traditional ones. Often, commercial thermal power plants equipped with powerful combined-cycle plants are not provided with contracts that guarantee year-round uninterrupted supplies of gaseous fuel, and must enter into non-guaranteeing contracts with several gas suppliers or be backed up by more expensive liquid fuel with an increase in the unit cost of TPP by 4-5%.
Since 65% of the life cycle costs of base and semi-peak thermal power plants are fuel costs, improving their efficiency is a major challenge. Its relevance today has even increased, taking into account the need to reduce specific emissions into the atmosphere.
In market conditions, the requirements for the reliability and readiness of thermal power plants have increased, which are now being evaluated from a commercial standpoint: readiness is necessary when the operation of a thermal power plant is in demand, and the price of unavailability at different times is significantly different.
Compliance with environmental requirements and the support of local authorities and the public are essential.
As a rule, it is advisable to increase the power during periods of peak load, even if it comes at the cost of some degradation in efficiency.
Special consideration is given to measures to ensure the reliability and readiness of thermal power plants. To do this, at the design stage, MTBF and mean recovery time are calculated and the commercial effectiveness of possible ways to improve availability is evaluated. Much attention is paid
improving and controlling the quality of suppliers of equipment and components, and in the design and construction of thermal power plants, as well as the technical and organizational aspects of maintenance and repairs.
In many cases, forced shutdowns of power units are the result of malfunctions with their plant auxiliary equipment. With this in mind, the concept of maintenance of the entire CHP plant is gaining ground.
Another significant development was the proliferation of branded services. The contracts for it provide for the contractor's guarantees for the performance of current, medium and major repairs within the specified time; the work is carried out and supervised by qualified personnel, if necessary in the factory; the problem of spare parts is mitigated, etc. All this significantly increases the readiness of HPPs and reduces the risks of their owners.
About fifteen or twenty years ago, the power industry in our country was at the most modern level, perhaps, except for gas turbines and automation systems. New technologies and equipment were actively developed, not inferior in technical level to foreign ones. Industrial projects were based on the research of powerful industry and academic institutions and universities.
Over the past 10-12 years, the potential in the electric power industry and power engineering has been largely lost. The development and construction of new power plants and advanced equipment have practically ceased. Rare exceptions are the development of gas turbines GTE-110 and GTE-180 and automated process control systems KVINT and Kosmotronik, which have become a significant step forward, but have not eliminated the existing backlog.
Today, taking into account the physical deterioration and obsolescence of equipment, the Russian energy industry is in dire need of renewal. Unfortunately, there are currently no economic conditions for active investment in energy. If such conditions arise in the coming years, domestic scientific and technical organizations will be able - with rare exceptions - to develop and produce advanced equipment necessary for the energy sector.
Of course, the development of its production will be associated with large costs for manufacturers, and the use - before the accumulation of experience - with a known risk for the owners of power plants.
We must look for a source to compensate for these costs and risks, since it is clear that our own production of unique power equipment is in line with the national interests of the country.
The power engineering industry can do a lot for itself by developing the export of its products, thereby creating accumulation for its technical improvement and quality improvement. The latter is the most important condition for long-term stability and prosperity.
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To assess the prospects of thermal power plants, first of all, it is necessary to understand their advantages and disadvantages in comparison with other sources of electricity.
Benefits include the following.
- 1. Unlike hydroelectric power plants, thermal power plants can be placed relatively freely, taking into account the fuel used. Gas-fired thermal power plants can be built anywhere, since the transport of gas and fuel oil is relatively cheap (compared to coal). It is desirable to place pulverized coal thermal power plants near sources of coal mining. To date, the "coal" thermal power industry has developed and has a pronounced regional character.
- 2. The unit cost of installed capacity (the cost of 1 kW of installed capacity) and the construction period of TPPs are much shorter than those of NPPs and HPPs.
- 3. The production of electricity at thermal power plants, unlike hydroelectric power plants, does not depend on the season and is determined only by the delivery of fuel.
- 4. The areas of alienation of economic lands for thermal power plants are significantly smaller than for nuclear power plants, and, of course, cannot be compared with hydroelectric power plants, whose impact on the environment may be far from regional. Examples are the cascades of hydroelectric power stations on the river. Volga and Dnieper.
- 5. Almost any fuel can be burned at TPPs, including the lowest-grade coals ballasted with ash, water, and rock.
- 6. Unlike nuclear power plants, there are no problems with the disposal of thermal power plants at the end of their service life. As a rule, the infrastructure of a thermal power plant significantly “survives” the main equipment (boilers and turbines) installed on it, and buildings, a turbine hall, water supply and fuel supply systems, etc., which make up the bulk of the funds, serve for a long time. Most of the TPPs built over 80 years according to the GOELRO plan are still operating and will continue to operate after the installation of new, more advanced turbines and boilers.
Along with these advantages, TPP has a number of disadvantages.
- 1. Thermal power plants are the most environmentally "dirty" sources of electricity, especially those that operate on high-ash sour fuel. True, to say that nuclear power plants that do not have constant emissions into the atmosphere, but create a constant threat of radioactive contamination and have problems with the storage and processing of spent nuclear fuel, as well as the disposal of the nuclear power plant itself after the end of its service life, or hydroelectric power plants, flooding huge areas of economic land and changing regional climate, are ecologically more "clean" is possible only with a significant degree of conventionality.
- 2. Traditional thermal power plants have a relatively low efficiency (better than nuclear power plants, but much worse than CCGT).
- 3. Unlike HPPs, TPPs hardly participate in covering the variable part of the daily electrical load schedule.
- 4. Thermal power plants are significantly dependent on the supply of fuel, often imported.
Despite all these shortcomings, thermal power plants are the main producers of electricity in most countries of the world and will remain so for at least the next 50 years.
Prospects for the construction of powerful condensing thermal power plants are closely related to the type of fossil fuel used. Despite the great advantages of liquid fuel (oil, fuel oil) as an energy carrier (high calorie content, ease of transportation), its use at thermal power plants will be increasingly reduced not only due to limited reserves, but also due to its great value as a raw material for petrochemical industry. For Russia, the export value of liquid fuel (oil) is also of considerable importance. Therefore, liquid fuel (fuel oil) at TPPs will be used either as a backup fuel at gas-oil TPPs, or as an auxiliary fuel at pulverized coal-fired TPPs, which ensures stable combustion of coal dust in the boiler under certain modes.
The use of natural gas at condensing steam turbine thermal power plants is irrational: for this, utilization-type combined-cycle plants based on high-temperature gas turbines should be used.
Thus, the distant prospect of using classical steam turbine thermal power plants both in Russia and abroad is primarily associated with the use of coal, especially low-grade coal. This, of course, does not mean the cessation of operation of gas-oil thermal power plants, which will be gradually replaced by PTU.
B.P. Varnavsky, Member of the Editorial Board of NT, Director for Energy Production and Capital Construction, OJSC EuroSibEnergo, Moscow
On the importance of thermal power plants in the Soviet Union
Combined heat and power plants (CHP) played a key role in the development of the energy system of the Soviet Union. Everyone was well aware that the intensive development of the industry needed a huge amount of electricity and, most importantly, industrial thermal energy. Based on this, it was CHPs that received fundamental development as a key form of energy supply for large industrial enterprises and cities in which (or near which) these industrial facilities were located.
For example, the Omsk Oil Refinery, which is included in the ranking of the world's top 100 refineries, is the only enterprise on this list that does not have its own block station, but receives heat and electricity from external thermal power plants.
In foreign countries, they went according to a different principle for the development of an energy supply scheme - each large industrial enterprise (with large volumes of thermal energy consumption, with a high yield of secondary resources and the need for their disposal) must have its own block station, which will ensure its needs for electricity and heat - energy. In this case, it becomes possible to optimize the power supply scheme of any such enterprise, avoiding intermediaries.
Speaking about domestic CHPPs, the number of which increased rapidly until 1990, it should be noted that in the Soviet years a type of thermal power plant was formed, which is (depending on the type of load) a balanced set of turbines of the PT, T and R types. A project appeared that received the name "Typical project of CHP-300", which was later upgraded to "Typical project of CHP-350", which greatly simplified the design of thermal power plants. It is known that, having standard solutions, it is much easier to develop a project, and it does not require the involvement of highly qualified specialists at this stage. The presence of such a standard project contributed to the emergence of unified building structures, individual elements, assemblies, circuit solutions (including a thermal circuit, with the exception of the type of fuel), etc. And today we work on this unified equipment almost throughout the country.
CHP operation in the post-Soviet period
Today, one can argue about the correctness of the chosen direction for the development of the energy system in
In the Soviet Union, but, of course, the choice made many years ago had a serious impact on the economic performance of thermal power plants in the post-Soviet period, when the industrial load of many of them, for various reasons, decreased significantly, and in some cases dropped to zero. Since now all industrial enterprises operate under market conditions, their production plan fluctuations are quite large, while the daily heat load of an enterprise can change two or more times (for example, fall from 800 to 400 t/h). As the practice of CHPP operation in the post-Soviet period has shown, the main troubles of CHPPs were their underloading and inflexibility in responding to changes in heat loads. Thus, CHPPs and power supply schemes from them, created in the Soviet era, were not ready to work in market conditions.
As a result, problems arose with heat loads for the needs of heat supply to other (non-industrial) urban facilities, which also decreased due to the disconnection of individual consumers from the CHPP. Suffice it to recall the boom that took place in 1990-2000, when decentralization of heat supply systems began in various regions of the country due to the sometimes thoughtless and unsupported by a feasibility study, the construction of attached and roof boilers, as well as equipping multi-storey residential buildings with apartment boilers. Moreover, it was believed that all these new technical solutions are much more economical and profitable compared to district heating systems (DH) from large boiler houses and CHPPs, but their operation (with the exception of individual cases) showed the opposite. And today, as before, CHP plants are considered the main element of DH systems.
Considering the DH system from CHP, one should not forget about reasonable heat supply radii. Probably, heating network radii of 20-30 km today cannot be considered acceptable values, not only from the point of view of efficiency, but also from the point of view of system reliability. We must not forget about the reliability of the system as a whole even if there is a large thermal power plant in the city, on which 500 thousand inhabitants “hang”, which is the only source for a particular territory. At the same time, increasing reliability due to redundancy at CHPPs is very expensive. First of all, at least, it must be protected from all sorts of emergencies in order to be able to cover its own needs and provide consumers with a thermal load. As for the electrical load, it is possible (of course, undesirable) to “lose” it, because. its redundancy can be provided by the common power system. But how to “not lose” the heat load of the station and the main heating system? Is it necessary to reserve the main heating networks from the CHPP (for example, with a diameter of DN 1200 mm) with the corresponding colossal financial investments? These questions have not yet been resolved.
There is another very important detail that needs to be paid attention to - the functioning of the heat supply system in Soviet times. Thus, the Soviet Union spent 50% of the extracted natural fuel resources to provide thermal energy to consumers; for electricity - 25%. Nevertheless, the normative and technical standardized arrangement of electricity generation was two orders of magnitude higher than that of thermal energy generation. In the heat supply sector, there were too few regulations allowing the creation of reliable energy sources and heat networks, in contrast to the electric power industry. If we follow the reliability criterion "n-1" (quantitative redundancy) adopted in the electric power industry, then it is difficult to shift it to the thermal power industry, since it sharply raises capital costs. There are no real revolutionary ways to improve the reliability of DH systems with large energy sources.
In our opinion, increasing the reliability of any DH system based on CHP does not consist in implementing measures based on the "n-1" criterion, but in increasing the reliability level of individual elements of the system (auxiliary, plant-wide equipment and heating network equipment) to the requirements for the main equipment of the plant, and the corresponding attitude towards it (i.e. in this case it will be considered that the failure of the system elements is comparable to the failure of the main equipment). For example, quantitative redundancy of main heat networks, when the existing main branch of heat networks of low quality is supplemented with a third pipeline of similar quality, is unlikely to lead to an actual increase in the reliability of the system with its significant increase in cost. But if there is a high-quality redundancy of the same pipelines of heating networks, which will allow you to practically forget about them for a declared resource of 25 years or more, then this is a completely different way to increase reliability, which in the end turns out to be cheaper than quantitative redundancy.
The situation is similar with pumping equipment. Maybe this is a revolutionary idea, but if a network pump with a high working life (for example, 15 years) will work in the system, which is achieved through the use of other materials, technical solutions (this is the task of the manufacturer), which has the same reliability as itself source of heat supply, then their number at the CHPP can be reduced to one piece. If such an approach to the level of requirements for auxiliary and other equipment in terms of reliability prevails, then manufacturers will make appropriate equipment according to these requirements. At the same time, the number of various fittings is reduced, the schemes are simplified, which will make them more reliable and understandable, despite the increase in capital costs. These circuits are easier to automate, it is easier to build an automated process control system on them, because. algorithms are simpler. If this approach is used in the development of technological progress, then such centralized systems will have the right to continue life.
The next serious question is what to do with thermal power plants that have exhausted their resources? Today there are projects to replace most of them. As for the electrical load, there are no questions here. But what to do with the heat load is not clear. On average, the standard service life of the plant's main equipment is 250,000 hours, and in Russia, most of the CHPP equipment has long ago reached this established standard service life. For example, the second stage of the Avtozavodskaya CHPP (Nizhny Novgorod) has worked 400 thousand hours, and 500 thousand residents of Nizhny Novgorod “sit” on it. Finally, a decision was made to replace the equipment of the second stage of this station. Question: how to carry out the replacement of capacities at existing CHPPs? Obviously, this should be the same site or close to it. Of course, the best option is the complete elimination of the old station and the construction of a new modern one, but this does not work out. For example, we considered a lot of options for Irkutsk: how to replace old CHPPs. It is clear that it is necessary to build up the appropriate capacity, and then remove the worn-out capacities, everything is logical, but where to get the free space. As a rule, almost all thermal power plants are industrial and heating, they are squeezed from all sides by all kinds of combines and factories, i.e. Thermal power plants are in conditions of absolute constraint. The construction of a CHPP on a new site with the transfer of heat networks is a very expensive pleasure. Thus, the urgency of the issue of replacing obsolete CHPPs is increasing every day, and there are no established principles of replacement, they need to be created. Someone has to take the initiative in resolving this issue.
Is this the task of each energy company separately or is it the task of the state, which should monitor the implementation of the energy strategy? But the replacement process is a strategic issue, not a tactical one. But today we are unlikely to expect any help from the state in solving this problem. Since we inherited just such a system from the Soviet Union, today we must know what to do with it next.
All CHPPs, as a rule, are participants in the wholesale electricity market. In this market, the interests of district heating, no matter how we declare them, are not taken into account. Although, in principle, the priority is formally given: when operating a CHP plant on the market or to cover the load of the dispatch schedule, there is an obvious decision made that it should operate under the conditions of 100% return of electricity generated in the combined cycle; CHP operation in condensing mode is not allowed, etc. But in real life, it is difficult for CHPPs to comply with these priorities, which means that it is not always possible to maintain those economic indicators that are protected in tariffs, etc. Therefore, a stricter framework should be established in this matter, and in this position I support A.B. Bogdanov that priorities should be given to the cost of electricity generated in the combined cycle, which is supplied by the CHP to urban residents, as he wrote about in a number of publications on the pages of the NT magazine (see series of articles
A.B. Bogdanov "Kotelnization of Russia - a disaster on a national scale" in the journal NT, published in the period 2006-2007 - Approx. ed.). Thus, the economic mechanisms for the operation of CHPPs are underdeveloped, as a result, their current situation throughout the country is very unstable.
We carried out an analysis of the increase in heat load at CHPPs in various cities of Russia, it turned out that these indicators basically stand still, because. a new connection to a thermal power plant looks more expensive than building your own boiler house. Until we change the state of affairs in this matter, we will mark time. Let us give an example of the Ust-Ilimskaya CHPP, which was once built to supply power to a pulp and paper mill located in close proximity to this power plant. In recent years, the plant has changed the range and reduced the volume of output, which, of course, affected the magnitude of the heat load and the operation of the CHPP and the ensuing problems that were discussed above. The Pulp and Paper Mill began to deal with energy saving issues, first of all, the waste of the enterprise (bark, sawdust, etc.), accumulated over the years, began to be utilized, the combustion of which makes it possible to fully cover the mill's own needs for thermal energy. Thus, today this enterprise no longer needs the previous volumes of heat load. The management of the Ust-Ilimskaya CHPP, realizing how this situation could affect the economic performance of the power plant, did everything possible to meet the needs of the pulp and paper mill, but it is possible to bid on the cost of a supplied gigacalorie of thermal energy only up to a certain value - up to its cost, below which the energy supply The company cannot go down. Thus, even our proposal for the supply of thermal energy from a thermal power plant at cost was inferior to the cost of thermal energy generated by the plant from its secondary resources. As a result, the CHPP lost most of the industrial withdrawals and, accordingly, the technical and economic indicators at the station fell seriously. We have given only one example, but it is not the only one, this trend, which is detrimental to existing CHP plants, continues. With such an undesirable trend, we must understand how it is possible to modernize the existing fleet of machines today to use P-type turbines, which turn out to be essentially unnecessary when the steam load is lost. Various schemes can be implemented here that would allow us to use P-type machines for the needs of heat supply to non-industrial consumers. Everything is good, except for one thing - it is necessary to expand the DH market from CHP.
For example, in Irkutsk, this market is expanding through the purchase of communal boiler houses and heating networks, which requires huge amounts of money. Then, as a rule, boiler houses are closed, the largest of them are transferred to peak mode. The heat networks accepted on the balance sheet of the generating company are without fail modernized - their condition is brought to an acceptable level, for which 3-4 times more money has to be invested in them than in the existing (main) heat networks of the generating company. In this case, it becomes possible to additionally load the CHPP only after the "transfer" of the thermal load of the boiler houses to it. Loading CHPPs in this way makes it possible to partially compensate for the costs incurred earlier due to the loss of industrial load. But similar and other programs (on energy saving, improving reliability) need government incentives, at least similar to that available in the electric power industry, because. for private companies that have entered the “big” energy sector today, such programs require colossal cash injections. At the same time, local authorities do not always take such decisions as in Irkutsk.
As another solution, let's take the example of St. Petersburg, where there are quite a lot of efficient boiler houses that are on the balance sheet of the State Unitary Enterprise "TEK SPb". Such boiler houses turn out to be quite competitive with CHPPs not in essence, but in terms of general economic indicators.
We have given several examples from which it is clear that in each individual case it is necessary to look for mechanisms that allow further development of combined heat and power generation, taking into account the introduction of new cycles, for example, a combined cycle.
During the introduction of CCGT in Russia, the question of its economic loading first of all arose. As soon as you "hang" the heating load at the CCGT, in the summer you still have to work in inefficient modes due to a decrease in the heat load, because. there is only a load on the DHW. For example, during the reconstruction of the Avtozavodskaya CHPP to replace the second stage of the station, we first of all equalized the parameters for live steam, selective steam, and heat extraction so that the new replacement unit could work in parallel with other queues. This drastically narrows the choice of gas turbines, since the turbines must provide exhaust parameters such that they can produce steam with parameters of 140 atm, 540 ° C at the CCGT waste-heat boiler. But in the future, this solution will allow loading this new unit based on the CCGT at full capacity , and less economical equipment will become the damper (despite the fact that it has high steam parameters). Thus, in the modernization and reconstruction of CHPPs, especially when introducing CCGT, it is necessary to use appropriate progressive schemes, which depend on a number of factors. The main criterion, of course, is the existing and prospective load of the CHPP.
Russia will remain a country in which the cost of production, all other things being equal, will always be higher due to the difference in average annual heating temperatures compared to foreign counterparts. Accordingly, the volume of fuel and energy resources (FER) required for the production of any unit of production in Russia will always be objectively higher compared to similar products manufactured abroad. Are we doomed to be forever uncompetitive due to objective reasons or not? There is only one way out: Russia must be half a length ahead of other countries in terms of the use and generation of various types of energy. For Russia, the situation is facilitated only by the fact that fuel and energy resources in our country are our own, and not imported, as in many foreign countries, respectively, we get them cheaper. It is necessary to constantly reduce the value of the fuel component in the production of any type of product, including heat and electricity. This requires not the isolated work of all Russian generating companies, but the coordination of all our efforts in terms of carrying out relevant research and development, R&D aimed at improving existing energy supply systems, etc.
Here it is also necessary to note one more point, which indirectly relates to the issue raised above. Today, any project for the construction of any object undergoes state examination for compliance with the criteria (for example, structural strength, etc.). In this regard, until the project passes this examination, a building permit will not be obtained. Everything is fine, but the existing expertise does not include criteria for the energy component. In our opinion, at the level of the state expertise of the project, the energy efficiency parameters of an object (primarily a large one) should be equated with its reliability parameters (strength, structural safety, etc.). Yes, this is an administrative resource, but it is necessary in the current Russian conditions. Thus, at the project stage, a decision should be made on the feasibility of building a particular facility, taking into account the parameters (criteria) indicated above.
When we are talking about the design of global facilities, it is necessary to take into account world experience, and at large enterprises located within the city, it is necessary to act in such a way that the “big” energy does not end up in the position of the Ust-Ilimskaya CHPP. Substitution at city-forming thermal power plants in today's conditions should be based on a guaranteed load of heat supply to the population, and not on an industrial load, which should be the concern of the industrial enterprises themselves!
In conclusion, it should be noted that the “large” energy sector should not forget about new technologies, for example, such technology as heat pumps. For example, in the city of Baikalsk (Irkutsk region), we faced a dilemma when introducing a heat pump in the presence of cheap electricity generated at a hydroelectric power station. As a result, we decided to install a heat pump in order to study the features of its operation, which should be taken into account in the further implementation of this technology. Maybe in some ways this position is flawed, but today it is impossible to reduce everything to pure profit, especially in the energy sector, there must be so-called altruistic (non-profitable) programs.
The negative environmental and social consequences of the construction of large hydropower plants make us look carefully at their possible place in the electric power industry of the future.
The future of hydropower
Large hydroelectric power plants perform the following functions in the power system:
- power generation;
- fast coordination of generation power with power consumption, frequency stabilization in the power system;
- accumulation and storage of energy in the form of potential energy of water in the Earth's gravitational field with conversion into electricity at any time.
Power generation and power maneuvering are possible at HPPs of any size. And the accumulation of energy for a period of several months to several years (for winter and dry years) requires the creation of large reservoirs.
For comparison: a car battery weighing 12 kg with a voltage of 12 V and a capacity of 85 ampere hours can store 1.02 kilowatt-hours (3.67 MJ). To store such an amount of energy and convert it into electricity in a hydraulic unit with an efficiency of 0.92, you need to raise 4 tons (4 cubic meters) of water to a height of 100 m or 40 tons of water to a height of 10 m.
In order for a hydroelectric power station with a capacity of only 1 MW to operate on stored water for 5 months a year for 6 hours a day on stored water, it is necessary to accumulate at a height of 100 m and then pass through a turbine 3.6 million tons of water. With a reservoir area of 1 sq. km, the level decrease will be 3.6 m. The same amount of output at a diesel power plant with an efficiency of 40% will require 324 tons of diesel fuel. Thus, in cold climates, storing water energy for the winter requires high dams and large reservoirs.
In addition, on b O In most of the territory of Russia in the permafrost zone, small and medium-sized rivers freeze to the bottom in winter. In these parts, small hydroelectric power plants are useless in winter.
Large hydropower plants are inevitably located at a considerable distance from many consumers, and the costs of building transmission lines and energy losses and heating wires should be taken into account. So, for the Trans-Siberian (Shilkinskaya) HPP, the cost of building a power line-220 to the Trans-Siberian Railway with a length of only 195 km (very little for such a construction) exceeds 10% of all costs. The costs of building power transmission networks are so significant that in China the capacity of windmills, which are still not connected to the grid, exceeds the capacity of the entire Russian energy sector east of Lake Baikal.
Thus, the prospects for hydropower depend on advances in technology and production, and storage and transmission of energy together.
Energy is a very capital-intensive and therefore conservative industry. Some power plants are still operating, especially hydroelectric power plants built at the beginning of the twentieth century. Therefore, in order to assess the prospects for half a century, it is more important to look at the rate of progress in each technology instead of volumetric indicators of a particular type of energy. Suitable indicators of technical progress in generation are efficiency (or percentage of losses), unit capacity of units, cost of 1 kilowatt of generation capacity, cost of transmission of 1 kilowatt per 1 km, cost of storage of 1 kilowatt-hour per day.
Energy storage
Storage Electricity is a new industry in the energy sector. For a long time, people stored fuel (wood, coal, then oil and oil products in tanks, gas in pressure tanks and underground storages). Then mechanical energy storage devices appeared (raised water, compressed air, super-flywheels, etc.), among which pumped-storage power plants remain the leader.
Outside the permafrost zones, the heat stored by solar water heaters can already be pumped underground to heat homes in the winter. After the collapse of the USSR, experiments on the use of solar heat energy for chemical transformations ceased.
Known chemical batteries have a limited number of charge-discharge cycles. Supercapacitors have much more O longer durability, but their capacity is still insufficient. Accumulators of magnetic field energy in superconducting coils are being improved very rapidly.
A breakthrough in the distribution of electricity storage will occur when the price drops to $1 per kilowatt-hour. This will make it possible to widely use types of power generation that are not able to operate continuously (solar, wind, tidal energy).
alternative energy
From technology generation Solar energy is undergoing the most rapid change right now. Solar panels allow you to produce energy in any required quantity - from charging your phone to supplying megacities. The energy of the Sun on Earth is a hundred times greater than the other types of energy combined.
Wind farms have gone through a period of declining prices and are in the process of growing towers and generators. In 2012, the capacity of all windmills in the world surpassed the capacity of all power plants in the USSR. However, in the 20s of the 21st century, the possibilities for improving windmills will be exhausted and solar energy will remain the engine of growth.
The technology of large hydroelectric power plants has passed its "finest hour", with every decade of large hydroelectric power plants being built less and less. The attention of inventors and engineers turns to tidal and wave power plants. However, tides and big waves are not everywhere, so their role will be small. In the 21st century, small hydropower plants will still be built, especially in Asia.
Getting electricity from heat coming from the bowels of the Earth (geothermal energy) is promising, but only in certain areas. Fossil fuel combustion technologies will compete with solar and wind energy for several decades, especially where there is little wind and sun.
The technologies for obtaining combustible gas by fermentation of waste, pyrolysis or decomposition in plasma are the fastest to improve. However, municipal solid waste will always require sorting (and preferably separate collection) before gasification.
TPP technologies
The efficiency of combined cycle power plants exceeded 60%. Re-equipment of all gas-fired CHPPs into combined-cycle (to be more precise, gas-steam) will increase electricity generation by more than 50% without increasing gas flaring.
Coal-fired and oil-fired CHPPs are much worse than gas-fired ones in terms of efficiency, equipment price, and the amount of harmful emissions. In addition, coal mining requires the most human lives per megawatt-hour of electricity. Gasification of coal will prolong the existence of the coal industry for several decades, but it is unlikely that the profession of a miner will survive into the 22nd century. It is very likely that steam and gas turbines will be replaced by rapidly improving fuel cells in which chemical energy is converted into electrical energy bypassing the stages of obtaining thermal and mechanical energy. So far, fuel cells are very expensive.
Nuclear power
The efficiency of nuclear power plants has grown the slowest over the past 30 years. Nuclear reactors, each costing several billion dollars, are progressing very slowly, and safety requirements drive up construction costs. The "nuclear renaissance" did not take place. Since 2006, in the world, the commissioning of nuclear power plants has been less than not only the commissioning of wind, but also solar. However, it is likely that some nuclear power plants will survive into the 22nd century, although due to the problem of radioactive waste, their end is inevitable. It is possible that thermonuclear reactors will also operate in the 21st century, but their small number, of course, “will not make a difference”.
Until now, the possibility of realizing a "cold fusion" remains unclear. In principle, the possibility of a thermonuclear reaction without ultrahigh temperatures and without the formation of radioactive waste does not contradict the laws of physics. But the prospects for obtaining cheap energy in this way are very doubtful.
New technologies
And a little fantasy in the drawings. Three new principles of isothermal conversion of heat into electricity are currently being tested in Russia. These experiments have a lot of skeptics: after all, the second law of thermodynamics is violated. So far one tenth of a microwatt has been received. If successful, batteries for watches and appliances will appear first. Then light bulbs without wires. Each light bulb will become a source of coolness. Air conditioners will generate electricity instead of consuming it. Wires in the house will not be needed. It is too early to judge when fantasy will come true.
In the meantime, we need wires. More than half of the price of a kilowatt-hour in Russia falls on the cost of construction and maintenance of power lines and substations. More than 10% of the generated electricity is spent on heating wires. “Smart grids” that automatically manage a multitude of consumers and energy producers can reduce costs and losses. In many cases, to reduce losses, it is better to transmit direct current than alternating current. In general, heating of wires can be avoided by making them superconductive. However, superconductors operating at room temperature have not been found and it is not known whether they will be found.
For sparsely populated areas with high transportation costs, the prevalence and accessibility of energy sources is also important.
The energy of the Sun is the most common, but the Sun is not always visible (especially beyond the Arctic Circle). But in winter and at night the wind often blows, but not always and not everywhere. Nevertheless, wind and solar power plants already now allow to significantly reduce the consumption of diesel fuel in remote villages.
Some geologists claim that oil and gas are formed almost everywhere today from carbon dioxide that gets underground with water. True, the use of hydraulic fracturing (“fracking”) destroys natural places where oil and gas can accumulate. If this is true, then a small amount of oil and gas (tens of times less than now) can be produced almost everywhere without prejudice to the geochemical carbon cycle, but exporting hydrocarbons means depriving oneself of the future.
The diversity of the world's natural resources means that sustainable power generation requires a combination of different technologies to suit local conditions. In any case, an unlimited amount of energy on Earth cannot be obtained for both environmental and resource reasons. Therefore, the growth in the production of electricity, steel, nickel and other material things on Earth in the next century will inevitably be replaced by an increase in the production of the intellectual and spiritual.
Igor Eduardovich Shkradyuk
