Author: ВИШНЕВСКИЙ АРСЕНИЙ РОМАНОВИЧ | VISHNEVSKY ARSENY
Introduction
This work is devoted to research in the field of energy, and concerns the study of the development of geographically isolated regions.
The relevance of the topic lies in the fact that in the modern world, most people cannot imagine life without electricity. In addition to convenience, it ensures the operation of important facilities: hospitals, civil defense structures, schools, kindergartens, industrial enterprises. But there are places where it is impossible or unprofitable to pull wires from the main line. In addition, even in a reliable and modern system, failures can occur. That is why the purpose of the study is to find solutions to the problem of energy supply to consumers in geographically isolated areas.
To achieve this goal, it is necessary to solve the following tasks:
to study the features of isolated territories;
to analyze the need for the use of renewable energy sources and the use of innovative technologies;
to design and develop such a power supply system that will increase the reliability and quality of power supply to decentralized power systems;
The object of the study is the decentralized energy systems of the Arctic.
The subject of the study is the peculiarities of the development of decentralized energy systems in the Arctic.
The following research methods were used in the performance of the work: analytical, computational and constructive, comparison method, classification.
Chapter 1. Features and priorities of the Arctic zone development.
Features of the Arctic regions.
The Arctic is the richest natural resource area of the Earth, including the outskirts of the continents of Eurasia and North America and adjacent to the North Pole.
The Arctic regions of Russia include the Murmansk and Arkhangelsk Regions; Krasnoyarsk Territory; Yamalo-Nenets, Nenets, Chukotka Autonomous Okrugs; the Republics of Karelia, Komi, Sakha (appendix, Fig.1)
Most of the territories of the Russian Federation (about 60-65%) are not provided with centralized electricity supply [7, 7]. Geographically isolated areas are located mainly in the northern part of the country: Kamchatka Krai, Magadan and Sakhalin Regions, Chukotka Autonomous Okrug and others.
The power supply systems of geographically isolated areas differ in significant features [2]:
1) harsh natural and climatic conditions: from low ambient temperature and the presence of permafrost to the specific terrain;
2) the predominance of sparsely populated areas, underdeveloped territories. Due to the predominance of a large area of territories with low density of electrical loads, sparsely populated areas, the transition to centralized power supply will require significant investments, and will also be extremely inefficient, since power plants will operate in a mode close to idle. As a result, the energy transfer will be accompanied by large energy losses due to an increase in voltage to unacceptable values and the generation of a significant amount of charging power by the lines;
3) low technical level of the energy sector caused by severe wear of equipment, which leads to low economic characteristics of energy sources;
4) currently, the energy industry of geographically isolated areas, as a rule, is based on long-range imported fuel-diesel, which is imported from other regions of the country according to complex logistical schemes, which leads to an increase in both cost and delivery time.
1.2 Priorities for the development of the Arctic zone
The Arctic, as an object of modern attention, covers social, economic, geopolitical, military and other aspects. It is a promising and attractive territory for every country with progressive interest and efforts in the current changes.
The Arctic region is a zone of strategic interests of the Russian Federation due to the reserves of the richest natural resources, of particular importance among which are hydrocarbons.
Russia's national priorities in the development of the Arctic are:
Maintaining peace and stability;
efficient development of Arctic resources;
development of science, technology, social sphere and economy of the region;
environmental protection and conservation of the region's ecosystem;
ensuring the interests of the indigenous peoples of the North;
creation of modern infrastructure and a unified information space in the region;
ensuring safe and stable navigation along the transport highway: The Northern Sea Route.
Priority in the development of the Arctic territories of Russia is given to the development of the energy and transport framework of the region.
The main aspects in the sustainable development of energy and the economy of the Arctic:
increase productivity through the introduction of energy-efficient, resource-saving and clean technologies;
differentiation of power supply schemes, including nuclear thermal power plants, including floating ones;
the introduction of innovative technologies that will help in the development of energy and transport infrastructure;
implementation of a complex of direct and indirect economic incentives for innovative energy development in the Arctic territories of the Russian Federation;
diversification of energy types;
meeting the ever-growing demand for electricity;
ensuring the security of the energy infrastructure.
Chapter 2. Selection of equipment and structure of the energy complex
2.1 Assessment of wind energy potential.
Wind energy potential is understood as the total energy of the wind flow of any area at a certain height above ground level.
The totality of the aerological and energy characteristics of the wind is combined into the wind energy cadastre of the region. The main characteristics of the wind energy cadastre are [3]:
- average annual wind speed, annual and daily wind speed;
- specific power and specific wind energy
To obtain reliable data on the average wind speeds of the territory, it is necessary to use significant amounts of measurements for a sufficiently long time [3].
The repeatability of wind speed by gradation is a time-dependent characteristic of wind speed. This characteristic is important for making wind energy calculations related to estimating the time intervals of operation of a power plant at different wind speeds.
The distribution of wind speed by gradation allows you to calculate the electricity generation received from the wind for each month. The total energy that wind turbines can generate over the time interval under consideration is defined as the sum of the energies corresponding to each wind gradation.
The results of the study of wind energy potential in the Arctic regions are the following characteristics:
determination of the average annual wind speed over the last 5-10 years according to meteorological observations;
calculation of the average wind speed at various altitudes from ground level;
the repeatability of wind directions and the average speed in the directions;
building a wind rose for a specific area.
The Arctic territories have great potential for the development of renewable energy. The key renewable source is the use of wind energy, since in the Arctic many areas are located along the northern maritime borders of Russia, where the average wind speed is more than 5-7 m/s, which is extremely attractive for the use of wind power plants.
In a number of Arctic regions, for example in Yakutia (Sakha Republic), in addition to wind turbines, solar panels can be used, in some regions the energy of sea waves and tides, as well as the energy of plant biomass.
The energy characteristics of renewable resources allow us to draw primary conclusions about the feasibility of using wind in the area under consideration.
The final version of the structure of the hybrid energy complex and the degree of participation of wind turbines in generating electricity is determined based on an analysis of the energy balance.
Chapter 3. Feasibility study of a wind diesel power plant (VDES)
3.1 Selection of a wind turbine and compilation of the energy balance of a hybrid wind turbine.
Over time, the requirements for the reliability of power supply and the quality of electricity for industrial and household consumers are increasing. Therefore, it is necessary to develop and modernize geographically isolated areas by introducing innovative technologies.
One of the most promising areas of such development is the creation of a hybrid power plant using several synchronized sources of electricity generation, including renewable sources with high substitution of diesel fuel by 50% or more, and a high degree of automation, which will reduce operating costs by at least 25% [5, 68]. This would not only lead to the preservation of a source of constant electricity generation, but would also reduce the supply of diesel fuel to geographically isolated regions and make energy production more environmentally friendly.
The choice of wind farm equipment is determined by the estimated amount of electricity produced and wind energy potential.
Vane wind turbines can be used as renewable sources of electricity (RES), but despite all their advantages, they have a lot of disadvantages, presented in Fig.4 of the appendix.
Due to these disadvantages, it is proposed to use a new type of device in a hybrid power plant - resonant wind turbines. Resonant wind turbines do not need blades, masts, or strong winds. The resonant wind generator shown in Fig.5 of the appendix is a turbine consisting of an external cylinder that is securely fixed only at the base. Under the influence of air currents, the upper part of the cylinder sways freely from side to side, like an antenna in the wind. At the same time, when the wind passes through a cone-shaped structure, according to the laws of aerodynamics, an air swirl and circular vortex flows form around it. According to the phenomenon of mechanical resonance, the frequency of natural vibrations of the system coincides with the frequency of the external force acting on the system, circular vortex flows, which leads to resonance - a sharp increase in the amplitude of the oscillation. The generator at the base of the cylinder converts mechanical energy into electrical energy by rotating a wire coil in a magnetic field [1, 47-49].
The structure is constructed using carbon and fiberglass reinforced polymers, as well as durable and lightweight materials used in conventional wind turbines. Its features allow the wind turbine not to wear out for a long time, and also minimize energy losses during fluctuations. It practically does not use movable elements such as gears, gears, shafts and all the same blades, so that production will cost at least half as much.
For the same reasons, as well as the absence of the need to use lubricants, the cost of maintenance will be reduced by as much as 80% compared to bladed wind generators.1 In addition, the innovation creates much less noise during operation, which is important due to the negative impact of low-frequency noise from modern wind farms on human and animal health, and the absence of blades eliminates the threat to birds. Greenhouse gas emissions from the production of resonant wind turbines are 40% lower than in the production of bladed wind turbines. The compactness of such an installation makes it possible to install entire fields of wind turbines at a minimum distance from each other, which is absolutely impossible in the case of classic wind turbines with blades.
However, you can get even more energy if you raise the turbine to a higher height. The largest wind turbine in the world has a height of about 240 meters and a capacity of about 4 MW. And what happens if you raise the turbine to 600 meters, where the wind speed is several times higher? The idea is to use the aircraft shown in Figure 6 of the appendix as a base for installing a turbine, which includes a light generator and a half-shell filled with helium. Externally, it resembles an airship with a turbine inside.
The use of industrial airship technologies will allow the device to rise to a height of at least 600 m, where the wind force is more stable and constant, which will allow the generator to generate at least 1200 Wh of electricity. A conventional station has a capacity of no more than 400 Wh. This follows from the calculations given below.
From calculations, it turns out that the power of a wind turbine raised to a height of 600 meters is 3.653 times more than the power of a wind turbine located at a level of 100 meters from the ground.
To make the difference more clearly visible, I will calculate the wind turbine power at a height of 10m according to formula (7) and wind speed according to formula (9) for some points in the Arctic regions and build a table with a rotor diameter of 4.5 m. To find the wind turbine power at altitudes of 100 and 600 meters, I will use the formula (10), and to find the area of the wind turbine, the formula (8).
The power characteristic of wind turbines, which connects electric power with wind speed, is convenient for analyzing electricity generation.
Based on the results presented in Table 2, I will plot the dependence of the power generated by the wind turbine on the average annual speed and altitude, shown in Fig. 7-11 of the appendix.
The device is fixed to the ground using lightweight and durable cables and can generate at least twice as much electricity as a ground-based generator. At the same time, the system is very light and, compared with a conventional wind turbine, its launch is much cheaper.
This device can be used in geographically isolated areas. It is mounted in just a few hours and is also easily packed into a regular shipping container. In addition, the use of wind energy allows you to save non-renewable resources. Thus, a 1 MW wind turbine saves 29,000 tons of coal or 92,000 barrels of oil in 20 years of operation.3
Questions arise: how can we save all the energy of the sun and wind by transferring it to consumers at the right time? How to make the system cheaper and more durable?
One of the problems of energy is the storage of excess energy obtained from renewable sources. This is especially true for developing solar and wind power plants, which are actively being introduced into the modern energy space. These installations often generate more electricity than the network can use at once, and therefore can generate energy cyclically. That is why companies that produce electricity need to store their surpluses somewhere. Usually very expensive batteries are used for this purpose.
Gravity batteries can be used to store energy and transfer it to the consumer.
This battery is shown in Fig.12 of the appendix and represents a storage of gravitational energy stored in an object as a result of height changes due to gravity. The system is able to respond to peak loads, that is, to provide the consumer with the necessary amount of energy at the right time, and also, in the event of an accident at a power plant, it will be able to provide uninterrupted supply of electricity to residents.
In charging mode, the system uses externally generated electricity to lift a heavy load from the bottom to the top. When lifting a load, the gravity battery accumulates potential energy. When it is necessary to extract energy and get electricity, the load is released under the force of gravity, and the electric motors switch to generator mode and provide electricity to the consumer, while the load does not fall instantly. The design is designed so that it is released slowly, that is, the system is capable of delivering energy for several hours, days, it all depends on the height to which the load rises and its mass. At the same time, switching from charging mode to discharge mode takes only a few secs5.
Gravity batteries do not tend to self-discharge over time compared to chemical batteries, which gradually lose their ability to hold stored energy, which is why after several decades they have to invest in their repair or replacement.
High-power batteries wear out quickly, are expensive, unsafe, and many chemicals are used in their creation, such as gadolinium and lithium, the production of which has its own environmental problems.
Unlike lithium-ion batteries, gravity batteries have a number of advantages:
1) cost: only for the cost of storing megawatts per hour, they are at least two times cheaper than lithium-ion;
2) Service life: Lithium-ion batteries degrade rapidly, and depending on the number of charge-discharge cycles, their service life is 5-10 years (gravity batteries can last at least 50 years);
3) Gravity batteries are safer to use.
The remnants of the coal industry can get a second life and give an impetus to the development of renewable energy. Abandoned coal mines can be repurposed to operate gravity batteries that can store enough energy to meet the current demands of the entire country. This is important because the main problem of collecting solar and wind energy is that if there is no place to store it, then it is simply wasted.
3.2 Choosing the structure of a wind-powered diesel power plant
Hybrid VDES systems are divided into three main types 6:
parallel;
The power supply to the power grid is carried out from different sources separately. When the load on the power system is peak, all sources will work at once, and at minimum loads one of the sources can generate electricity.
consistent;
Renewable energy sources or generators, in case the wind speed is too low and there is no sun, charge the batteries. The electricity received from the batteries after conversion to the required parameters is sent to the general power system. Such a station can operate in both automatic and manual mode.
switchable
Electricity is supplied to consumers directly from a generator or rechargeable and other types of batteries, renewable sources after passing through a device that converts direct current into alternating current with a change in voltage, called an inverter. The batteries are charged separately as they are used. The control controllers, at the same time, independently connect the necessary modules, depending on performance and load. Such systems have high flexibility and are more reliable.
The scheme of the hybrid energy complex, shown in Fig.13 of the appendix, provides for the unification of all sources of electricity on an AC bus.
During the period when a large amount of electricity is generated by renewable sources, the diesel power plant is turned off. Fluctuations in the power consumed and generated from renewable energy sources are damped by the supply of electricity in uninterruptible power supplies, which reduces the number of starts of a diesel power plant.
The great advantage of an inverter diesel power plant is to reduce fuel consumption in low-load operating modes by reducing the rotational speed of the diesel generator. Often, rectifier inverter frequency converters are used as voltage converters in such systems, which are part of modern wind farms.
conclusion
The Arctic is an important region of the Russian Federation that needs to be developed. The solutions presented in the work, supported by analytical calculations, tables, technical and economic, design and graphical justification, will help in solving the problem of energy supply to consumers remote from the centralized power system.
Analyzing all of the above, it can be noted that the creation of a hybrid power plant using renewable energy sources (resonant wind turbines, air-based wind turbines) will open up new horizons for energy development, will be able to increase the efficiency, environmental friendliness and reliability of energy supply, as well as the quality of electricity transmitted to consumers in geographically isolated areas. The use of energy storage systems, such as gravity batteries, will reduce the use of diesel fuel, in the event of an accident at the main source, and provide consumers with uninterrupted power supply.
The full material of the work is presented in the appendix (with figures, formulas and tables)