Currently, humanity uses all possible ways to generate electricity. It is difficult to overestimate the importance of this resource. Moreover, its consumption is growing every day. For this reason, more and more attention is being paid to non-traditional methods of generating electricity. At the same time, these sources at this stage of development cannot fully satisfy the needs of the earth's population. This article briefly examines the main traditional and alternative methods of generating electricity.
Producing electricity at thermal power plants
This method of generating electricity is the most common. For example, in the Russian Federation, thermal sources account for almost 80% of the total production of the necessary resource. Years go by, environmentalists are practically shouting about the negative impact of such engineering structures on the environment and human health, but stations built in the middle of the last century (or even pre-revolutionary ones) continue to supply populated cities and large industrial enterprises with electricity.
Thermal sources are traditional methods of generating electricity. And for the past three or four decades they have been occupying a leading position in the ranking in terms of production volumes. This is despite the rapid development of alternative methods of generating electricity.
Among all engineering projects, a special type of structure is distinguished. These are combined heat and power plants, the additional function of which is to supply houses and apartments with heat. According to experts, the efficiency of such power plants is extremely low, and the transfer of the generated resource over long distances is associated with large losses.
Energy generation is carried out as follows. Solid, liquid or gaseous fuel is burned, heating the water in the boiler to significant temperatures. The power of the steam rotates the turbine blades, causing the turbine generator rotor to rotate and generating electricity.
Electrification of energy production. Transport
Modern energy (in a general sense) and utility systems are becoming increasingly electrified. Due to the deployment of more and more distributed energy generation systems and therefore distributed energy storage, local (traditional) fuel-based or renewable energy sources and energy storage technologies must be able to become interconnected - to serve a site, campus, city or any area. In such cases, for example, natural gas generators, microturbines, fuel cells, solar photovoltaic systems, wind power plants, combined heat and power cogeneration systems (cogeneration plants) can be used to generate electricity. The method of storing chilled water and heating it instead of burning fossil fuels maximizes the utilization of electricity generated by renewable energy sources, as well as the economic efficiency of electrical energy storage systems. In turn, electrical distribution and transmission systems must be able to accommodate greater electrification of the energy sources and storage loads themselves.
To meet these conditions, microgrids have been used for several years. As a localized electrical grid, campuses and other similarly sized areas can generate and store electricity from a variety of distributed energy resources, including renewable energy sources. By balancing supply and demand resources (including thermal and electrical loads) within certain boundaries, it is the microgrid system that provides resiliency, energy efficiency and cost savings.
Another important point, which at some point began to influence the load on power grids, is associated with a change in the paradigm of personal vehicles. As consumer choice shifts toward electric vehicles and other alternative modes of transportation, it becomes increasingly important to address the need for adequate infrastructure to power these electrified vehicles. Similar to the variable capacity of renewable energy sources, the variable load due to electric vehicle charging will likely exceed the ability of existing power generation systems to meet growing demand. It's easy to imagine a scenario in which all employees come to work at the same time and charge their electric vehicles - or vice versa, when people return home at the end of the day and plug them in to charge too. Integrating additional energy storage resources into the electrical system can help provide required energy in the most cost-effective manner, using pre-stored energy during off-peak periods so that the system can respond quickly to increased demand.
Hydroelectric power plants are a promising way to generate electricity
The construction of complex engineering structures designed to convert water energy into electricity began in the Russian Empire. Many years have passed since then, but this source is still actively used. During the years of industrialization of the USSR (1930s), giant hydroelectric power stations grew throughout the country. All the forces of a young and fragile country were thrown into the construction of these giants (the Zaporozhye hydroelectric power station alone is worth it!). Engineering structures of those years are still in use and generate significant amounts of electricity.
Currently, the state is relying on the development of “green” methods of generating electricity. Therefore, the construction of modern and very productive hydroelectric power plants throughout the country is being actively financed. The strategy of constructing small-scale facilities on small tributaries of rivers has fully justified itself. One such station can fully satisfy the electricity needs of small adjacent settlements. Nationwide, this will lead to increased efficiency of the national economy and the competitiveness of domestic manufacturers of industrial goods.
The disadvantages of this technology include the high cost of such objects and very long payback periods. The main costs are for the construction of the dam. But it is necessary to erect the building itself (administrative and engine buildings), build a device for discharging water, and so on. The parameters and composition of the structure depend on many factors: the installed power of the generators and water pressure, the type of power plant (dam, run-of-the-river, diversion, storage, tidal). Hydroelectric power plants on large navigable rivers also have complex navigation locks and canals to facilitate the migration of fish to spawning grounds.
Energy storage systems
A variety of tools and technologies are available to capture the energy produced in a short period of time for future use. Electrical and thermal energy storage systems are the most common, so when designing modern facilities and engineering systems, they are used by utilities, which, in turn, offer building occupants benefits such as greater resiliency, cost savings, increased energy efficiency and ease of use of energy of any type.
Electric Energy
The largest increase in energy storage system installations over the past decade has been for electrical systems such as batteries and capacitors. Lithium-ion batteries have quickly become the workhorse batteries commonly used in today's large energy storage systems. In addition, such batteries are also key components in the rapidly growing fleet of electric vehicles.
An example of an efficient battery is the one built by Elon Musk in Australia. It was put into operation on December 1, 2022 (Fig. 1) [4], and already on December 14 it was able to show itself in action during a failure at a local coal power plant.
Rice. 1. The new system from Tesla is part of ongoing efforts to solve energy problems in South Australia, where residents are suffering from constant power surges and blackouts.
In addition, so-called flow or buffer batteries are being developed that can be used taking into account the required peak capacity and duration of compensation for the missing energy. Their role can be played by capacitors - devices that store electrical energy in the form of electrostatic charge accumulated on their conductive metal plates without chemical conversion.
The energy accumulated in a capacitor is described by the formula known from school:
W = 1/2Q2/C = 1/2C × V2,
where Q is the amount of charge stored on the capacitor, C is the capacitance of the capacitor, and V is the voltage across the capacitor.
As can be seen from the above equation, the maximum amount of energy that can be stored in a capacitor depends on the capacitance as well as the maximum voltage rating of the capacitor. The stored energy can be quickly released from the capacitor due to the fact that capacitors have extremely low internal resistance. This property is often used in systems that are subject to large load surges. When a capacitor is connected to a power source, it stores energy (charges without requiring special chargers). If additional energy is needed, the capacitor releases the accumulated energy (discharges), in this respect it is similar to a battery. The difference is that a battery, as already stated, uses electrochemical processes to store energy, while a capacitor simply stores electrical charge. Thus, capacitors can release stored energy at a much higher rate than batteries because the chemical processes take longer to transform the energy and release it from the battery. However, much more often, capacitors are used to compensate for reactive power that leads to losses in power grids.
Mechanical systems
Mechanical energy storage systems convert electrical energy into potential or kinetic energy and store it that way, converting it back to electrical energy when needed. Typically, systems based on this approach include large pumped storage pumps (an example of an effective application of pumped storage power plants is shown in Fig. 2), mechanical flywheels and compressed air storage devices.
Rice. 2. Dniester PSPP (Ukraine). The estimated design capacity in turbine mode is 2268 MW (seven hydraulic units of 324 MW each), which makes it the seventh most powerful pumped storage power plant in the world, the design water pressure is 147.5 m
Thermal systems
Thermal energy storage allows thermal energy (hot or cold) to be stored and later used to balance energy demand between daytime and nighttime consumption or even across different climate seasons. Most often, such a system is implemented in the form of tanks for storing cooling water or heating water (Figure 3), which can be generated during periods of lower energy consumption and then released at peak times, supporting a peak load limiting strategy. Other thermal energy storage systems include molten salts, ice storage, and cryogenics.
Rice. 3. Thermal energy storage supports a peak load shaving strategy by storing cooled or heated water generated during periods of lower electricity demand for use during periods of higher demand. Project by Affiliated Engineers
Chemical systems
In addition to battery systems, which are typically based on an electrochemical process, other chemical energy storage systems are available, for example through hydrogen generation and storage. Electrical energy is used to produce hydrogen from water by electrolysis. The hydrogen is then compressed and stored for future use in hydrogen fuel generators or fuel cells, turning back into water.
This approach can store large amounts of energy, but it is not necessarily the most efficient. The problem is that it itself is energy-intensive, since it requires a large amount of energy to separate hydrogen from water, natural gas or biomass, store the gas by compression or liquefaction, and transfer the energy carrier to the user. Also, some energy is lost when converted into useful electricity with fuel cells. The most practical option so far remains the production of hydrogen from natural gas - methane, CH4. One example of such an installation is shown in Fig. 4, but in this case energy is still required to extract it. Only about 25% remains for practical use.
Rice. 4. Electrolysis is used to produce hydrogen; after generating it, the hydrogen is compressed or liquefied and stored for later use in generators or fuel cells. Image courtesy of Affiliated Engineers
Nuclear power
Today, a nuclear power plant will no longer surprise anyone. Such facilities began to be actively built back in the USSR. Therefore, this technology belongs to traditional methods of generating electricity.
Nuclear power plants are currently being actively built not only in Russia, but also in countries near and far abroad. For example, a company with Russian roots, Rosatom, finances the construction of such a source in the Republic of Belarus. By the way, this station will be the first in this territory.
The world's attitude towards nuclear energy is very ambiguous. Germany, for example, has seriously decided to completely abandon the peaceful atom. And this is at a time when the Russian Federation is actively investing in the construction of new facilities of the latest generation.
Scientists have reliably established that nuclear fuel deposits in the bowels of the earth are much larger than all hydrocarbon reserves (oil and gas). The constantly growing demand for hydrocarbons leads to their rise in price. This is precisely why the development of nuclear energy justifies itself.
Wind energy
Wind power on an industrial scale has emerged relatively recently and has added to the list of unconventional methods of generating electricity. And this is a very promising technology. With a high degree of probability, it can be said that in the distant future, wind turbines will generate as much electricity as humanity needs. And these are not empty words, because according to the most conservative estimates of scientists, the total force of the wind on the surface of the globe is at least a hundred times greater than the power of all water resources.
The main problem is the variability of air flows, which entails difficulties in predicting energy production. Over the vast territory of Russia, winds constantly blow. And if you learn to use this inexhaustible resource efficiently and effectively, then you can more than satisfy all the needs of heavy industry and the country's population.
Despite the obvious advantages of using wind energy, the volume of electricity generated by wind power plants does not exceed one percent of the total. Equipment for these purposes is very expensive; in addition, such facilities will not be effective in every area, and transporting electricity over long distances is associated with large losses.
Benefits from using energy storage systems
Energy storage systems can be used to maintain stability of supply, reduce costs and ensure the sustainability of the energy system as a whole. The return on investment will depend on local utility prices, any available utility incentive programs for peak power demand reduction, on-site power generation capabilities, and the specific load profile of a particular facility. Investments can return quite quickly: for example, Elon Musk’s battery, shown in Fig. 1, according to the Renew Economy report [4], in just a few days the owners earned 1 million Australian dollars, or $800 thousand. Moreover, Australia is one of the leaders in the development of renewable energy, and the presence of an effective way to store such energy makes it extremely cheap.
Another advantage of energy storage systems is their fast response time. Most storage technologies can make up for shortfalls in electricity grid capacity very quickly, while fossil fuel-based sources tend to add additional capacity rather slowly. This speed is important to ensure a stable power supply in cases where unexpected load increases occur. As a joke that well illustrates the problem, one can cite an episode from the famous film “National Lampoon's Christmas Vacation”, 1989, where Clark Griswold suddenly turned on all 25 thousand Christmas lights. It was necessary to launch an additional nuclear reactor at the nuclear power plant; before it was connected, some areas of the city were de-energized.
Backup power
Energy storage systems can provide a reliable source of backup power in the event of a loss of utility power due to severe weather or other problems. By helping assets remain operational, such systems eliminate losses due to reduced downtime and provide increased resilience to critical situations. An uninterruptible power supply is one example, but a larger scale is possible.
Peak limitation and load shifting
The demand-response functionality of energy storage systems allows them to participate in utility incentive programs that aim to reduce energy use during periods of peak load on the electrical grid.
Energy prices tend to be highest during periods of peak demand. Limiting the maximum peak load is usually achieved by shifting a number of loads to times of lower electricity demand, for example through price incentives to the consumer using multi-tariff electricity meters. However, if the loads themselves or their operating times cannot be time-corrected, the use of one or another energy storage technology should be considered.
It is energy storage systems that can support smoothing of electrical power consumption to reduce energy costs. In this case, for example, the battery can be charged during periods of low load - at night or during periods of lower consumption during the day, and also, like Elon Musk's battery (Fig. 1), using alternative energy sources. This battery is then discharged during periods of high load or outage, mitigating the impact of heavy loads and voltage failures within the facility or the power system as a whole. This approach is most cost-effective for utility customers whose tariff is based on peak energy demand.
Load shifting (also called "tariff steering") is similar to peak shaving, but instead of focusing solely on peak prices, it aims to reduce overall costs per kWh. Essentially, it takes advantage of the difference between low and high energy costs, storing energy at low costs and releasing energy at high costs. Load shifting typically provides additional value to a system that already provides other benefits, such as peak (maximum) load limitation.
Renewable energy and its problems
When a renewable energy source cannot meet current power demand due to unsuitable weather conditions (lack of sufficient sunlight or wind power) or available generation does not meet peak energy demands, an energy storage system can compensate for these gaps, while supplying additional energy from conventional no power sources are required. Without energy storage or other dispatchable generation sources, fluctuations in renewable energy sources can create destructive imbalances that prevent grid stability from being maintained.
Rice. 5 . One of the ten largest solar power plants Topaz Solar Farm in 2015, California, USA [5]
Energy storage also captures excess energy generated by renewable sources, storing it until periods of high demand. This is more likely to apply to areas with large numbers of solar installations, such as California (Figure 5), where the electrical grid is saturated with photovoltaic energy even at times when it cannot be fully utilized. A graph that describes energy consumption based on its shape is often called a duck curve (literally, “duck-shaped curve,” Fig. 6).
Rice. 6. A duck profile plot displays net power loads throughout the day, illustrating periods of potential oversupply and power shortages. Image courtesy of Affiliated Engineers
The "duck curve" represents the payload throughout the day. The origin of this term can be traced to data provided by the California Independent System Operator starting in 2012 [2]. This non-profit independent system operator oversees the operation of the power grid, transmission lines and electricity market. For a more detailed explanation, consider areas where peak energy demand occurs after sunset, i.e., when solar energy is no longer available. In cases where the power system primarily uses solar energy (during daytime), other sources must be available at other times of the day to take on the load during peak power demand times.
The electricity demand curve, which represents the total load minus the power generated by solar power, as already mentioned, resembles the silhouette of a duck. At the point of peak demand, one of two energy supply options is required. Utilities, in order to take action when and where PV production has stopped in real time, must either connect other generation sources or rely on energy storage. Since energy storage is a much more flexible and faster solution, as well as a more economical and sustainable solution, it is certainly the most preferred option.
As the duck curve phenomenon becomes more common, disparities in hourly energy rates are growing. In California, daily electricity rates have doubled over the past three years compared to the previous price per MWh, despite the fact that the price of electricity at noon due to excess generation from solar power plants has sharply dropped to $15 per MWh. Battery storage can help mitigate these problems and smooth out the variability in the cost of electricity depending on the time of day.
Electrical energy quality
Energy storage systems have another important advantage - the possibility of frequency regulation. This allows a specific object to support the operation of the power system as a whole and solve one of its main tasks, namely to ensure a constant frequency of the generated alternating current voltage. As you know, the electrical system is always in a dynamic state and constantly balances between supply (generation) and demand (consumption). The ability of a stand-alone energy storage system to absorb or release energy, and quickly compensate for demand peaks, represents a potential revenue-generating balancing service and a necessary additional buffer against the power quality issues that often characterize renewable energy generation systems.
Increases in utility charges are often associated with loads on low power factor facilities. The higher cost comes from lower power factors, and low power factors can cause power quality problems. An energy storage system can improve a facility's capacity factor while providing improved power quality and savings on monthly utility bills.
Geothermal energy
The development of geothermal sources marked a new milestone in the history of the development of alternative methods of generating electricity.
The principle of generating electricity is the flow of kinetic and potential energy of steam from hot water from an underground source into the blades of a generator turbine, which produces current through rotational movements. In theory, the difference in temperatures on the surface and deep in the earth's crust is characteristic of any area. However, it is usually minimal, and it is not possible to use it to generate electricity. The construction of such stations is justified only in certain areas of our planet (seismically active). Iceland is a pioneer in the development of this method. The lands of Russian Kamchatka can also be used for these purposes.
The principle of obtaining energy is as follows. Hot water from the depths of the earth comes to the surface. The pressure here is much lower, which causes the water to boil. The separated steam is directed through a pipeline and rotates the blades of the generator turbines. It is difficult to predict the future of this modern method of generating electricity. Perhaps such stations will begin to be built en masse on the territory of the Russian Federation, or perhaps this idea will fade over time and no one will remember about it.
Types of energy sources in the future
Fusion energy
Alternative energy sources derived from natural resources are very effective. However, the most powerful energy sources will still be created by man. For example, this concerns a new scientific project that involves the creation of a thermonuclear reactor that will be able to recreate the process occurring inside a star. According to all forecasts, this will be the most powerful source of energy ever created by man.
Initially, the reactor was launched in 2016. However, the complexity of the technological solutions used required a delay in the launch of the project. Now experts say that it can be put into effect no earlier than 30-40 years of the twenty-first century.
Antimatter as an energy source
Not so long ago, this method of generating energy could be classified as science fiction. However, modern technologies, according to many experts, will make it possible to use antimatter as an energy source in the near future.
As you know, antimatter is matter consisting of antiparticles. It has the same mass as ordinary matter but has the opposite atomic property (a process known as charge and spin).
Energy can be obtained from antimatter by colliding different particles, which leads to the release of huge amounts of energy. This process was described and calculated by the famous physicist Albert Einstein.
Antimatter energy is already used in medicine, but in the future it will be used as a super-powerful energy source. However, before that, scientists will have to solve many more technical issues. Including how to obtain the necessary antimatter. How to store it so that it is safe and secure.
Harvesting ocean thermal energy
The world's oceans amaze the imagination with their scale. Experts cannot give even an approximate estimate of the amount of thermal energy accumulated in it. Only one thing is clear - a colossal amount of resources remains unused. Currently, prototypes of power plants have already been built that convert the heat energy of ocean waters into current. However, these are pilot projects, and there is no certainty that this area of energy will receive further development.
Ebbs and flows in the service of the electric power industry
Converting the powerful force of the tides into valuable derivatives is a new way to generate electricity. The nature of these phenomena is now known and does not evoke the awe that arose among our ancestors. The culprit is the influence of the magnetic field of the planet’s faithful satellite – the Moon.
The most noticeable tidal currents are observed in the shallow waters of seas and oceans, as well as in river beds.
The first station that really produced results was built back in 1913 in Great Britain near Liverpool. Since then, many countries have tried to repeat the experience, but ultimately abandoned this idea for various reasons.
Tidal power plants.
The water level changes 4 times during the day, such fluctuations are especially noticeable in the bays and mouths of rivers flowing into the sea. To set up a simple tidal power plant (TPP), you need a pool - a dammed bay or a river mouth. The dam has culverts and installed turbines. Double-acting PES (turbines operate when water moves from the sea to the pool and back) are capable of generating electricity continuously for 4-5 hours with breaks of 1-2 hours four times a day.
The first tidal power plant with a capacity of 240 MW was launched in 1966 in France at the mouth of the Rance River, which flows into the English Channel, where the average amplitude of tides is 8.4 m. Despite the high cost of construction, which is almost 2.5 times higher than the costs for the construction of a hydroelectric power station of the same capacity, the first experience of operating a tidal power station turned out to be economically justified. The power plant on the Rance River is part of the French energy system and is being used efficiently. In 1968, a pilot industrial power plant with a design capacity of 800 kW came into operation on the Barents Sea. The place of its construction - Kislaya Bay - is a narrow bay 150 m wide and 450 m long. There are projects of large tidal power plants with a capacity of 320 MW (Kola) and 4000 MW (Mezenskaya) on the White Sea, where the tidal amplitude is 7-10 m. It is also planned to use the enormous energy potential of the Sea of Okhotsk, where in some places, for example in Penzhinskaya Bay, the tidal height reaches 12.9 m, and in Gizhiginskaya Bay - 12-14 m. In 1985, a tidal power plant was put into operation in the Bay of Fundy in Canada with a capacity of 20 MW (amplitude The tide here is 19.6 m). Three small tidal power plants have been built in China. In the UK, a 1000 MW tidal power plant project is being developed in the Severn Estuary, where the average tidal range is 16.3 m.
From an environmental point of view, PES have an undeniable advantage over thermal power plants that burn oil and coal. Favorable preconditions for the wider use of tidal energy are associated with the possibility of using the recently created Gorlov helicoidal turbine, which allows the construction of tidal power plants without dams, reducing the cost of their construction. The first damless TPPs are planned to be built in the coming years in South Korea.
Solar energy
In fact, all natural fossil fuels were formed millions of years ago with the participation and influence of sunlight. Thus, we can say that humanity has been actively using products obtained from the sun for a long time. As a matter of fact, we owe the presence of rivers and lakes to this inexhaustible source, which ensures the water cycle. However, this is not what modern solar energy means. Relatively recently, scientists were able to develop and produce special batteries. They generate electricity when sunlight hits their surface. This technology refers to an alternative method of generating electricity.
The sun is perhaps the most powerful source of all currently known. In three days, planet Earth receives as much energy as is not contained in all explored and potential deposits of all types of thermal resources. However, only 1/3 of this energy reaches the surface of the earth's crust, and most of it is dissipated in the atmosphere. And yet we are talking about colossal volumes. According to experts, one small reservoir receives as much energy as a fairly large thermal power plant produces.
There are installations around the world that use the energy of solar rays to produce steam. It turns the generator and generates electricity. However, such installations are very rare.
Regardless of the principle by which electricity is generated, the installation must be equipped with a collector - a device for concentrating solar rays. Surely many have seen solar panels with their own eyes. It seems that they are under dark glass. It turns out that such a coating is the simplest collector. The principle of its operation is based on the fact that dark transparent material transmits sunlight, but retains and reflects infrared and ultraviolet radiation. Inside the battery there are tubes with a working substance. Since thermal radiation is not transmitted through the dark film, the temperature of the working fluids significantly exceeds the ambient temperature. It should be noted that such solutions work effectively only in tropical latitudes, where there is no need to turn the collector after the sun.
Another type of coating is a concave mirror. Such equipment is a very expensive solution, which is why it has not found widespread use. Such a collector can provide heating up to three thousand degrees Celsius.
This direction is rapidly developing. In Europe, you will no longer surprise anyone with houses disconnected from the electrical grid. However, electricity is not generated by this method on an industrial scale. The roofs of these houses have solar panels. This is a very dubious investment. In the best case, the installation of such equipment will pay for itself only after ten years of operation.
Lecture No. 3. Modern methods of generating electrical energy
Section 3
Lecture No. 3
Modern methods of generating electrical energy
The development of technology and engineering has stepped far forward, which has made it possible to create new sources of electrical energy generation. Among the main types of electricity generation, experts identify the following: thermal, nuclear, hydropower and alternative types of electricity. This process is carried out at power plants.
In the case of thermal generation, electrical energy is obtained as a result of the combustion of various types of organic fuel. In this way, electricity is produced at thermal power plants (TPPs). Thermal power plants come in two types: condensing power plants (CHP) and combined heat and power plants (CHP). Cogeneration power plants produce both thermal and electrical energy. The operating principles of condensing and heating power plants are quite similar. Their main difference is that cogeneration power plants use part of the heated steam for heat supply.
Nuclear energy is represented by nuclear power plants (NPPs). Very often, nuclear power is not distinguished separately, but is perceived as a subtype of thermal power. This is due to the fact that the principle of generation at a nuclear power plant is virtually the same as at a thermal one.
The next method of generating electricity is hydropower. The entire process takes place at hydroelectric power plants (HPPs). Here, the kinetic energy of water flow is used to generate electrical energy. Among the types of hydroelectric power plants, it is worth noting pumped storage power plants (PSPP). In fact, they cannot be called powerful sources of electrical energy, since during their operation they consume almost as much energy as they produce. However, in some cases they are used to relieve network load.
Another way to generate electrical energy is alternative energy. As its name implies, it includes various non-traditional, or alternative, sources of electrical energy. Many of them were developed by various scientists in order to save the planet’s natural resources or in order to reduce the harm from generating electrical energy to the environment. For example, in wind energy, electrical energy is obtained from the kinetic energy of the wind. In solar energy, electrical energy is obtained from the energy of solar rays. There is also geothermal energy. In this case, the heat of the Earth is used to generate electrical energy.
Electricity production is a separate industry. Currently, the largest share of electricity is produced at three types of power plants:
· TPP (thermal power plant)
· HPP (hydroelectric power station)
NPP (nuclear power plant)
Thermal condensing power plants
Thermal condensing power plants ( IES
) convert the energy of organic fuel first into mechanical and then into electrical. The mechanical energy of the ordered rotation of the shaft is obtained using heat engines that convert the energy of the disordered movement of steam or gas molecules.
All heat engines are divided into:
· according to the type of working fluid used - steam
or
gas
;
· according to the method of converting thermal energy into mechanical energy - piston
or
rotary
In the piston method, the potential energy of the working fluid obtained when it is heated is used for conversion. The rotary method uses the kinetic energy of particles of the working fluid moving at high speed.
At thermal power plants, the chemical energy of burned fuel is converted in a steam generator (boiler) into the energy of water steam, which drives a turbine unit (steam turbine connected to a generator). The mechanical energy of rotation is converted by the generator into electrical energy. The fuel for power plants is coal, peat, oil shale, as well as gas and fuel oil. In the domestic energy sector, CPPs account for up to 60% of electricity generation.
The generator is located on the same shaft as the turbine. At thermal power plants, turbine and boiler units, together with auxiliary equipment, are connected into independent units. The number of units at a station usually reaches 8–12, and the station’s power is 4000–6000 MW. The block is like a separate power plant. Connections between adjacent blocks along technological lines are usually not provided. The construction of IES on a block principle provides certain technical and economic advantages, such as simplification of the technological scheme, convenience of expanding the power plant in blocks, reducing the volume of construction and installation work, and reducing capital costs for the construction of the power plant.
The use of large units allows for a rapid increase in power plant capacity and an acceptable cost of electricity. The maximum power of a IES is determined by the water supply conditions and the impact of plant emissions on the environment.
Figure 3.1 shows a general view of a modern IES unit. The IES technological scheme consists of several systems: fuel supply; fuel preparation; main steam-water circuit together with a steam generator and turbine; circulating water supply, water treatment, ash collection and ash removal and, finally, the electrical part of the station.
The operation of the main units of the unit is provided by auxiliary machines, the activation of which requires electricity. At thermal power plants, electricity is spent on preparing fuel, supplying water to boilers, controlling equipment, etc. Mechanisms and installations that ensure the normal functioning of all these elements are included in the so-called
auxiliary system of
the station. The power spent on the unit's own needs is 4-8% of its capacity.
| Figure 3.1. Schematic flow diagram of IES: 1‑fuel storage and fuel supply system; 2‑fuel preparation system; 3‑steam generator; 4‑turbine; 5‑capacitor; 6‑circulation pump; 7‑condensate pump; 8‑feeding pump; 9‑burner steam generator, 10‑fan; 11‑smoke exhauster; 12‑air heater; 13‑water economizer; 14‑low pressure heater; 15‑deaerator; 16‑high pressure heater. |
The greatest energy losses at IES occur in the main steam-water circuit, namely in the condenser, where the exhaust steam, which still contains a large amount of heat expended during steam formation, transfers it to the circulating water. Heat with circulating water is carried away into reservoirs, that is, it is lost. These losses mainly determine the efficiency of the power plant, which is no more than 40 - 42% even for the most modern CPPs.
The electricity generated by the power plant is supplied at a voltage of 110 - 750 kV and only part of it is selected for its own needs through an own needs transformer connected to the terminals of the generator. Generators and step-up transformers are connected into blocks and connected to the high voltage switchgear.
Turbines
. The superheated steam obtained in steam generators at a temperature of ~600°C and a pressure of 30 MPa is transferred through steam lines to the nozzles. The nozzles are designed to convert the internal energy of steam into the kinetic energy of the ordered movement of molecules.
After leaving the nozzle, the steam is supplied to the turbine blades. If the turbine is active, then steam expansion does not occur between its working blades, therefore, the steam pressure does not change. The absolute speed of steam movement decreases due to turbine rotation.
In a jet turbine, the steam passing through the channels of the working blades expands. Depending on the steam expansion rates in the turbine channels, they are characterized by degrees of reactivity.
Capacitors
. The steam leaving the turbine is sent to cool and condense in special devices called condensers. The capacitor is a cylindrical body, inside of which there is a large number of brass tubes. Cooling water flows through the tubes, entering the condenser usually at a temperature of 10-15ºС, and leaving it at a temperature of 20-25ºС. Steam flows around the tubes from top to bottom, condenses and is removed from below. The pressure in the condenser is maintained within 3-4 kPa, which is achieved by cooling the steam.
The cooling water consumption is approximately 50-100 kg per 1 kg of steam. A power plant with a capacity of 1 GW consumes 40 m3/s of cooling water, which is approximately equal to the water consumption in the Moscow River.
If water for cooling steam is taken from the river, supplied to a condenser, and then discharged into the river, then such a water supply system is called direct-flow. In cases where there is not enough water in the river, a pond is built. On one side of the pond, water is supplied to the condenser, and the water heated in the condenser is discharged to the other side of the pond.
In closed water supply cycles, cooling towers
, which are devices approximately 50 m high. Water flows out in streams from the openings of the trays, splashes and, flowing down, cools. Below is a pool in which water is collected and then pumped into the condenser.
The main features of IES are the significant distance from direct consumers of electricity, which mainly determines the output of power at high and ultra-high voltages, and the block principle of constructing a power plant. The location of the power plant depends not only on the conditions for supplying it with primary energy resources, but also on the availability of sufficient water. The power of modern CPPs is usually such that each of them can provide electricity to a large region of the country. Hence another name for power plants of this type - state district power station
(
GRES
).
Combined heat and power plants
The production of electrical energy at thermal stations is accompanied by large heat losses. At the same time, many industries, such as chemical, textile, food, metallurgy, and a number of others, require heat for technological purposes. Heating residential buildings requires significant amounts of hot water.
Under these conditions, it is natural to use steam produced in steam generators at thermal stations, both for generating electricity and for heating consumers. Power plants that perform such functions are called combined heat and power plants
(
CHP
). This type of power plant is intended for centralized supply of industrial enterprises and cities with electricity and heat. Features of the technological scheme of the thermal power plant are shown in Figure 3.2.
The steam exhausted in the turbines of condensing stations has a temperature of 25-30ºС, and therefore it is unsuitable for use in technological processes in enterprises.
To obtain steam with the parameters required by consumers, special turbines with intermediate steam extractions are used. In such turbines, after part of the steam energy is consumed to drive the turbine and its parameters decrease, a certain portion of the steam is selected for consumers. The remaining portion of the steam is then used in the turbine in the usual manner and then enters the condenser.
Figure 3.2. Features of the technological scheme of the thermal power plant:
1- network pump; 2 — network heater
With such combined generation of electricity and heat, significant fuel savings are achieved compared to separate energy supply, that is, generating electricity at CPPs and receiving heat from local boiler houses. Therefore, thermal power plants have become widespread in areas (cities) with high consumption of heat and electricity. Thanks to more complete utilization of thermal energy, efficiency CHP reaches 60-65%, and efficiency. IES – no more than 40%.
Hot water and steam under pressure, reaching in some cases 3 MPa, are delivered to consumers through pipelines. A set of pipelines designed to transfer heat is called a heat network
.
The main difference lies in the specifics of the steam-water circuit and the method of generating electricity. The specifics of the electrical part of a thermal power plant are determined by the position of the power plant near the centers of electrical loads. Under these conditions, part of the power can be supplied to the local network directly at the generator voltage. Excess power is supplied, as in the case of IES, into the power system at increased voltage.
An essential feature of the CHP plant is also the increased power of the thermal equipment compared to the electrical power of the power plant, taking into account the heat output. This circumstance predetermines a higher relative consumption of electricity for own needs than for IES.
Gas turbine units.
Gas turbine units are beginning to be widely used at domestic thermal stations
(
GTU
). The working fluid in such installations is a mixture of fuel combustion products with air or heated air at high pressure and high temperature. In gas turbines, the thermal energy of gases is converted into kinetic energy of rotation of the turbine rotor.
Modern gas turbines mainly operate on liquid fuel, however, in addition to liquid fuel, gaseous fuel can be used: both natural combustible gas and artificial gas obtained by special combustion of solid fuels of any type.
Figure 3.3. Schematic diagram of a power plant with gas turbines.
KS - combustion chamber; KP - compressor; GT - gas turbine; G - generator; T - transformer; D - starting electric motor.
The basis of modern gas turbine power plants are gas turbines with a capacity of 25-100 MW. A simplified schematic diagram of a gas turbine power plant unit is shown in Figure 3.3.
Fuel (gas, diesel fuel) is supplied to the combustion chamber, and compressed air is pumped into it by a compressor. Hot combustion products give off their energy to a gas turbine, which rotates a compressor and a synchronous generator.
The installation is started using an accelerating engine and lasts 1-2 minutes, and therefore gas turbine installations are highly maneuverable and suitable for covering load peaks in power systems. The overall efficiency of gas turbine power plants is about 30%.
Combined-cycle plants
The exhaust gases leaving the gas turbine plant have a high temperature, which adversely affects efficiency. thermodynamic cycle. Combined-cycle plants have been developed to increase the efficiency of gas turbines
(
PGU
). In them, fuel is burned in the furnace of a steam generator, the steam from which is sent to a steam turbine. The combustion products from the steam generator, after they have been cooled to the required temperature, are sent to the gas turbine. Thus, the CCGT has two electric generators driven into rotation: one by a gas turbine, the other by a steam turbine. In this case, the power of the gas turbine is about 20% of the steam one.
Combining gas and steam turbine units in such a way that they share the heat obtained by burning fuel makes it possible to increase the efficiency of the operation of the unit, called combined cycle gas, by 8-10% and reduce its cost by 25%.
Combined-cycle plants using two types of working fluid – steam and gas – are classified as binary. In them, part of the heat obtained by burning fuel in a steam generator is spent on the formation of the necessary steam parameters, which is then sent to the steam turbine (Fig. 3.28). Gases cooled to a temperature of 650-700ºC fall on the working blades of a gas turbine. The gases exhausted in the turbine are used to heat the feed water, which reduces fuel consumption and increases efficiency. of the entire installation, which can reach approximately 44%.
Lecture No. 4
Hydraulic power plants
At hydraulic power plants ( HPPs)
) the energy of water flows (rivers, waterfalls, etc.) is used to generate electricity. Currently, hydroelectric power plants produce about 15% of all electricity. More intensive construction of this type of stations is hampered by the specific distribution of hydro resources across the territory of the Russian Federation (most of them are concentrated in the eastern part of the country).
The primary engines at hydroelectric power plants are hydraulic turbines, which drive hydrogenerators. The power developed by the hydraulic unit is proportional to the pressure N
and water flow
Q
:
R
=
H
Q
, _
where Q
– flow rate, m3/s,
N
– pressure, m.
The power of the hydraulic station is greater, the greater the amount of water supplied to the blades of the hydraulic turbine Q
and the greater the pressure
H
it has.
To increase the pressure H, artificial hydraulic structures are created. On lowland rivers, pressure is created using a dam. The water space in front of the dam is called the upstream, and below the dam is called the downstream (Figure 3.4). The difference between the levels of the upper (UVB) and lower pool (UNB) determines the pressure H
. The hydroelectric complex on a flat river includes: a dam, a power plant building, spillways, navigation gates (locks), fish passage structures, etc.
Hydroelectric power stations are being built on mountain rivers, which take advantage of the large natural slopes of the river. However, in this case it is usually necessary to create a system of diversion structures - bypass canals. These include structures that direct water bypassing the natural riverbed: diversion channels, tunnels, pipes.
In the electrical part, hydroelectric power plants are in many ways similar to condensing power plants. Like CPPs, hydroelectric power plants are usually located far from consumption centers, since the location of their construction is determined mainly by natural conditions. Therefore, the electricity generated by hydroelectric power plants is supplied at high and ultra-high voltages (110 - 500 kV). A distinctive feature of hydroelectric power plants is the low consumption of electricity for their own needs, which is usually several times less than at thermal power plants. This is explained by the absence of large mechanisms in the system of auxiliary needs at hydroelectric power stations. Electricity consumption is caused by technical water supply, control of hydraulic and electrical equipment, cooling of generators, etc. At large hydroelectric power plants, their own electricity consumption is a fraction of a percent of total output.
Figure 3.4. Schematic flow diagram of a hydroelectric power station.
In hydraulic turbines, the energy of water is converted into mechanical energy of rotation of the turbine shaft. A turbine is called active if its operating principle is based on the use of dynamic water pressure, and reactive if static pressure is used with the reactive effect.
In modern hydropower, three types of turbines are mainly used:
1. Radial-axial turbine (Francis turbine). The blades of the impeller of this turbine have a complex curvature, due to which the water entering the blades from the guide vane gradually changes direction from radial to axial. The number of blades for such turbines is 10-30. The radial-axial turbine operates at a power of over 100 MW.
2. Rotary-blade turbine (Kaplan turbine). The turbine impeller is made in the form of a propeller screw, the blades of which, depending on the load, can be rotated to achieve the greatest efficiency. The turbine was proposed in 1913. Czech scientist Kaplan.
3. Bucket turbine (Pelton turbine). The turbine blade is made in the form of a double bucket with a sharp knife in the middle. In the buckets, the direction of the speed of water movement changes by 180º, as a result of which centrifugal forces act on the blades. For the most complete conversion of water energy into mechanical energy of the turbine, the speed of movement of the blades is chosen such that at their output the absolute speed of water movement is zero.
During the construction of hydroelectric power stations, important national economic problems are solved simultaneously with energy ones: land irrigation and the development of navigation, ensuring water supply to large cities and industrial enterprises.
The technology for generating electricity at hydroelectric power plants is quite simple and easy to automate. Starting up a hydroelectric power plant unit takes no more than 50 seconds, so it is advisable to provide power reserves in the power system with these units.
The power of a hydroelectric power station is regulated as follows. During periods of time when there are load dips in the system, hydroelectric power plants operate with insignificant power and water fills the reservoir. At the same time, energy is stored. With the onset of peaks, the station’s units are turned on and their power increases by the required amount.
The efficiency of hydroelectric power plants is usually about 85-90%. Due to lower operating costs, the cost of electricity at hydroelectric power plants is usually several times lower than at thermal power plants.
Pumped storage power plants
The production of electricity at power plants and its consumption by various receivers are processes interconnected in such a way that, due to physical laws, the power consumption of electricity at any point in time must be exactly equal to the generated power.
The load graph of a certain area or city, which represents the change over time in the total power of all consumers, has dips and maxima. This means that during some hours of the day a large total power of generators is required, and at other times some generators or power plants must be switched off or must operate at reduced load. The number of power plants and their capacity are determined by the relatively short maximum load of consumers. This leads to underutilization of equipment and increased cost of energy systems. Thus, reducing the number of hours of use of the installed capacity of large thermal power plants from 6000 to 4000 hours per year leads to an increase in the cost of generated electricity by 30-35%.
In industrialized countries, the majority of electricity (80%) is generated in thermal power plants, for which a uniform load schedule is most desirable. Thermal station units are poorly adapted to power regulation. Conventional steam boilers and turbines at these stations allow load changes of only 10-15%.
PSPP) play a special role in modern energy systems
), serving to solve the problem of removing load peaks. These power plants have at least two pools - an upper and a lower one with certain elevation differences between them (Figure 3.5). At time intervals when the electrical load in the combined systems is minimal, the pumped storage power plant pumps water from the lower reservoir to the upper one and consumes electricity from the system. In the mode of short “peaks” - maximum load values - the PSPP operates in generator mode and consumes the water stored in the upper reservoir.
Figure 3.5. Scheme of pumped storage power plant
So-called reversible hydraulic units are installed in the pumped storage power plant building. During the hours of minimum load on the power system, pumped storage power plant generators are switched to motor mode, and turbines are switched to pumping mode. Consuming power from the network, such hydraulic units pump water through a pipeline from the lower basin to the upper one. During periods of maximum load, when there is a shortage of generating capacity in the energy system, the pumped storage power plant generates electricity. By releasing water from the upper basin, the turbine rotates the generator, which supplies power to the network.
Pumped storage power plants have become especially effective after the advent of reversible hydraulic turbines, which perform the functions of both turbines and pumps. The number of cars in this case is reduced to a minimum - two. However, stations with a two-machine layout have a lower efficiency value. due to the need to create approximately 1.3 - 1.4 times more pressure in pumping mode to overcome friction in water pipelines. In generator mode, the pressure value is less due to friction in the water pipes. In order for the unit to operate equally in both generator and pump modes, it is possible to increase its rotation speed in pump mode. The use of different rotation speeds in reversible generators leads to more complex and expensive designs.
Thus, the use of pumped storage power plants helps to level out the load schedule of the energy system, which increases the efficiency of operation of thermal and nuclear power plants.
Tidal power plants
There are a significant number of projects for the energy use of sea and ocean energy: wave power plants using wave energy; ocean thermal stations based on the temperature difference between sea water at the surface and at depth; installations using the energy of ocean currents. TPPs – have received industrial use.
.
The energy of sea tides, or, as they sometimes say, “lunar energy,” has been known to mankind since ancient times. This energy has been used since ancient times to drive various mechanisms, especially mills. In Germany, tidal wave energy was used to irrigate fields. Tides for turning mill wheels were used 1000 years ago in Spain, France, and England. Today, TPPs operate in China, France, Russia (Kislogubskaya TPP on the Barents Sea has a capacity of 1200 kW) and some other countries.
Tidal power plants ( TPP
) differ favorably from river ones in that their work is determined by cosmic phenomena and does not depend, like river ones, on numerous random weather conditions.
The most significant drawback of PES is its uneven performance. The unevenness of tidal energy during the lunar day and lunar month, which differ from the solar one, does not allow its systematic use during periods of maximum consumption in the systems.
PES operate under conditions of rapid pressure changes, so their turbines must have high efficiency. at variable pressures. Currently, a fairly advanced and compact double-action horizontal turbine has been created. The electric generator and part of the turbine parts are enclosed in a waterproof capsule, and the entire hydraulic unit is immersed in water (Figure 3.6). Rotating impeller blades provide high efficiency. at various pressures starting from 0.5 m. For PES, reversible turbines are used, when the rotation is continuous in any direction of water movement.
Figure 3.6. PES diagram:
1 – capsule unit; 2 – step-up transformer; 3 – gantry crane for servicing gates and gratings; 4 – cable corridor; 5 – overhead crane of the machine room
The hydraulic unit can operate in both generator and pump modes. When the generator is turned off, the hydraulic unit can directly transfer water from the sea to the pool and back. In pump mode, it can pump water from the sea to the pool and thereby increase the water pressure.
Tidal stations are built in bays with a narrow passage. They block the entrance with a dam and install hydrogen generators in it. During high and low tides, water flows through pipes to the hydraulic turbines and rotates them, and therefore the electric generator, which sits on the same shaft as the turbine.
PES generate electrical energy by using the potential energy of the tides of the sea. The magnitude of the tide (as a result of the attraction of the Moon) is not the same in different places on Earth: off the coast of America it is 21 m, off the coast of France and England - about 15 m, off the coast of Russia - 8-11 m in the White and Okhotsk Seas. It has been established that it is advisable to use tidal energy even at 3–4 m tide height.
Nuclear power plants
Nuclear power plants ( NPP
) are essentially thermal power plants that use the thermal energy of nuclear reactions. Nuclear power plants use nuclear fuel to produce electricity and heat. Nuclear power plants use a substance as fuel that is capable of spontaneous fission of atomic nuclei, releasing energy in the form of heat. The most important nuclear fuels are heavy elements: uranium-235 (U-235), uranium-233 (U-233), plutonium-239 (U-239). Instead of a boiler unit, nuclear power plants use a nuclear reactor and special steam generators.
At a nuclear power plant, the energy obtained as a result of the fission of uranium nuclei into fragments is converted into thermal energy of steam or gas and then into electrical energy, that is, into the energy of the movement of electrons in a conductor. The fission of uranium nuclei occurs when they are bombarded with neutrons, resulting in fragments of nuclei, usually unequal in mass, neutrons and other fission products, which fly in different directions at enormous speeds and, therefore, have large amounts of kinetic energy. The energy obtained from nuclear fission is almost completely converted into heat. A facility in which a controlled nuclear fission chain reaction occurs is called a nuclear reactor
.
They mainly use nuclear reactions of fission of uranium U-235 under the influence of slow (thermal) neutrons. The fission of U-235 nuclei occurs in a chain reaction, releasing a large amount of thermal energy (83%) and so-called nuclear radiation (17%). To carry out the reaction of fission of uranium nuclei in the reactor, in addition to fuel (U‑235), there must be a neutron moderator and, of course, a coolant that removes heat from the reactor.
In Russia, the construction of nuclear power plants is based on pressurized water reactors - VVER
(
water
-
water energy reactor
) and boiling channel uranium-graphite reactors -
RBMK
(
high- power boiling
reactor ).
In VVER
Ordinary water under pressure is used as a moderator and coolant.
In RBMK
Water is used as a coolant, and graphite is used as a moderator.
Despite the existence of several types of thermal neutron reactors, they all have some common elements, shown in Figure 4.7. The reactors have a so-called core 1, into which nuclear fuel containing uranium-235 and a moderator (usually graphite or water) is loaded. To reduce neutron leakage, the active zone is surrounded by a reflector 2, behind which there is a concrete shield 5 from radioactive radiation. The amount of nuclear fuel in the reactor significantly exceeds the critical mass. Therefore, a strong neutron absorber in the form of boron carbide rods 4 is introduced into the core. As the fuel burns out, the control rods are removed from the core. The heated coolant is discharged through pipes 3 to the heat exchanger-steam generator 6, where it transfers its heat to the working fluid (for example, water passing through the coils and turning into steam). The working fluid (steam) enters turbine 7, rotates the turbine shaft connected to the generator shaft 8. The steam exhausted in the turbine enters condenser 9, after which the condensed water again goes into the heat exchanger.
The operating principle of nuclear reactors is the same: inside the reactor there are fuel
elements
-
fuel rods
, which consist of a metal tube made of zirconium alloy filled with a mixture of uranium-235 and uranium-238.
In a VVER reactor, all fuel rods are placed in a steel casing filled with water, which is in direct contact with the fuel rods and cools them. The heat from a nuclear reactor heats the water under high pressure, causing it to become radioactive. Therefore, this water is sent to the intermediate steam generator, where the secondary circuit water is converted into steam, which is sent to the turbine.
The RBMK reactor is filled with graphite blocks with holes made inside them. They contain thin-walled pipes (working channels) made of zirconium, in which fuel rods are installed. Water under pressure circulates through the pipes, it removes heat from the fuel rods and partially evaporates.
Figure 4.7. Simplified diagram of a nuclear power plant:
1 - active zone; 2 - reflector; 3 - pipes; 4—neutron absorber; 5 - concrete protection; 6 — heat exchanger-steam generator; 7 - turbine; 8 - generator; 9 - capacitor
RBMK is a channel reactor, and VVER is a pressure vessel reactor. VVERs are more widely used than RBMKs. The advantage of the RBMK is the ability to replace fuel rods without shutting down the reactor.
The power of a power reactor is determined by the ability to quickly remove heat from the core. The main part of the energy released during a nuclear reaction in fuel rods goes to heating the nuclear fuel, and a small part goes to heating the moderator. Since heat removal occurs due to convective heat exchange, to increase the intensity of the heat removal process, it is necessary to increase the speed of the coolant. Thus, the speed of water movement in the core is approximately 3-7 m/s.
The rapid development of nuclear energy is caused by its advantages compared to other methods of energy generation. Let's name the main ones:
1. Nuclear power plants are almost independent of the location of sources of raw materials due to the compactness of nuclear fuel and its easy transportation. However, to cool a nuclear power plant, a powerful source of water (sea or fresh) is required. Therefore, nuclear power plants, as well as thermal power plants, depend on water sources;
2. The construction of powerful energy units has favorable prospects, since from one reactor it is possible to obtain electrical power of the order of 2 GW;
3. Low fuel consumption does not require vehicle loading;
4. Nuclear power plants, during trouble-free operation, practically do not pollute the environment.
Radioactive radiation is dangerous. Taken in large doses, it can cause illness and even death in people. The effects of radioactive radiation on people and animals are now quite well studied. Due to close attention to radioactive radiation and numerous experiments, the impact of studying on ecology has been studied much more than the influence of synthetic compounds and some other factors.
Ionizing radiation in humans has somatic (from the Greek word meaning “body”) and genetic effects. A noticeable clinical effect occurs with powerful irradiation of approximately 0.2 J/kg for a short time. Long-term chronic exposure can increase the static likelihood of clinical consequences such as cancer and other diseases.
All nuclear reactors have special biological shielding to protect operating personnel from dangerous radioactive radiation that causes ionization of cell molecules.
Using sea currents
This is a very unusual way of generating electricity. Due to the temperature difference in the northern regions of the oceans and the southern (equatorial) regions, powerful currents arise throughout the volume. If you immerse a turbine in water, a powerful current will rotate it. The operating principle of such power plants is based on this.
However, at present this energy source is not actively used. There are still many engineering problems to be solved. Only experimental work is being carried out. The British are the most active in this direction. It is possible that in the near future, colonies of power plants will appear off the coast of Great Britain, the blades of which will be driven by sea currents.
Solar space power plants.
The atmosphere prevents us from receiving and using “clean” solar energy on the Earth’s surface, so projects are emerging to locate solar power plants in space, in low-Earth orbit. Such stations have several advantages: weightlessness makes it possible to create multi-kilometer structures that are necessary to generate energy; the transformation of one type of energy into another is inevitably accompanied by the release of heat, and releasing it into space will prevent dangerous overheating of the earth's atmosphere.
Designers began designing solar space power plants (SCPS) back in the late 60s of the 20th century. Several options were proposed for transporting energy from space to Earth, but the most rational was considered to be the proposal to use it at the site of generation, for this it is necessary to transfer the main consumers of electricity (metallurgy, mechanical engineering, chemical industry) to the Earth's satellite the Moon or asteroids. Any version of the SKES assumes that this is a colossal structure, and more than one. Even the smallest SCES must weigh tens of thousands of tons. Modern launch vehicles are able to deliver the required number of blocks, assemblies and solar panels to a low reference orbit.
The construction of solar space power plants now seems like a fantasy, but soon, perhaps, the first solar power station will appear, which will give rise to a new level of energy development.
Methods for generating electricity at home
Electricity can also be generated at home. And if you take this issue seriously, you can even satisfy your household's electricity needs.
First of all, it should be noted that some of the listed methods for generating electricity are quite applicable in private households. Thus, many farmers and simply owners of country estates install windmills on their plots. You can also increasingly see solar panels on the roofs of country houses.
There are other ways to produce electricity, but their practical application is out of the question. This is more likely for fun, or for the purpose of experiment.
Types of Alternative Sources
In order to live comfortably in our own home, we need two types of energy: electrical and thermal. It is not difficult to obtain both varieties from the environment. From what sources can this be obtained, and what devices are used for this:
- solar panels and collectors;
- wind generators;
- installations using biogas;
- heat pumps.
Humanity has been using all these devices and technologies for a long time. For example, consider wind or water mills. Today, science, which is constantly moving forward, offers a wide range of devices with which you can obtain heat and electricity.
It is better to install two different energy sources for your home Source ast75.ru
True, each home requires its own devices, which will be more efficient in each case. Experts recommend choosing not just one variety, but several at once. For example, solar panels are good to use in warm, cloudless seasons. Wind generators work great in windy weather. That is, if you install both units in the house, you can guarantee the constant availability of electric current, regardless of weather conditions.
Now let's look separately at the energy sources themselves and the devices that generate heat and electric current.
Solar panels
Let's just say that these devices are becoming more and more in demand and popular over the years. Today, manufacturers produce and sell them in two variations:
- Ready-made batteries that are simply installed on the roofs of houses, connecting each other into a single complex.
- Individual photocells . This option is offered to craftsmen who assemble them into panels themselves, adjusting them to the required amount of energy received.
Solar panels on the roof of a house Source yandex.net
Photocells used in solar panels are also of two types:
- Monocrystalline . Note that these are more efficient, that is, with a higher efficiency, and durable elements. Accordingly, they are more expensive. But their high efficiency is achieved only if the sky is clear and the elements receive a stable solar flux.
- Polycrystalline . This type has lower efficiency and service life. But they can work even in cloudy weather. And this is a big plus.
Photocells are usually placed under transparent material and framed with a metal profile. The entire structure is installed on a special stand that can be rotated. This is done so that the solar panels can be rotated to catch direct sunlight. And their angle of inclination depends on the time of year.
But solar panels are just part of the package. Harvesting electrical energy requires batteries, which are connected to the panels through an inverter system. The former accumulate electricity, the latter converts sunlight into electricity.
Batteries for solar panels Source autogear.ru
Attention! A competent choice of batteries and inverter system – maximum efficiency of the entire complex. In this case, the specialist must accurately carry out the required calculations, which will ensure that the required volume of electric current is obtained for the entire house.
Today, manufacturers offer devices that differ from solar batteries and operate on the same principle.
- Flexible film that is installed on glass windows with access to the sunny side. This option does not have the highest efficiency, but due to the reduction in the size of the material and the complexity of installation, the method is quite popular.
- Betaray is a glass ball of quite impressive size. Its task is to focus the sun's rays and direct them into a photocell in one stream. In essence, the ball acts as a lens. This installation rotates about its axis. The rotation is programmed, so the ball strictly moves after the sun. Hence the high efficiency of solar radiation selection. This installation works well even at night, collecting light from the moon and stars. As practice has shown, this power is enough to illuminate night lamps.
So, that's all about solar panels, let's move on to another type of non-traditional energy source - solar collectors.
Betaray system - solar battery Source nemcd.com
See also: Catalog of companies that specialize in the development and installation of utility networks for private homes
Solar collectors
Everyone is familiar with the summer shower, which includes a metal barrel. Water is poured into it, and it heats up under the influence of the sun. Collectors work on exactly the same principle. Only they have a large area of absorption of sunlight.
And this area is nothing more than pipes arranged in the form of a coil. The pipes heat up and transfer their heat to the water, which moves through them. In this case, the movement always occurs from the bottom up - this is the law of physics. That is, when heated, water or air always tends upward.
A tank is installed at the top of the complex through which tap water passes. Inside the tank there is another coil connected to the collector, that is, a large coil. It turns out that water moving through the pipes of a large coil and heating up there enters the coil located inside the tank. It gives off its thermal energy to the water in the tank, cools down and descends to the lower part of the collector. And everything repeats itself again.
This is how the water in the tank is heated, which is then used in everyday life. The most important thing is that the natural circulation of water makes it possible not to use pumps in the system.
Note that industrially manufactured solar collectors are more complex devices. But their operating principle is the same. Simply, instead of water, freon is poured into a large coil, which works effectively even in winter.
Solar collector on the roof of a house Source baltgazservice.ru
Wind generators
This is another commonly used type of alternative energy. Purely structurally, these devices are ordinary windmills, which include a generator. The rotation of the windmill blades is transmitted to the rotation of the generator rotor. This is how electricity is generated, which is collected in batteries.
High power wind generators Source golos.io
The standard type of devices is a body with blades that are mounted on a high support. Today, manufacturers offer other design solutions.
- Mobile installation . It can be unfolded and installed in a short time, and just as quickly it can be folded and transported to another place. A wind turbine is installed on a car platform.
- Aircraft installation . Essentially, it is a kite with several turbines mounted on it. It is simply launched into the sky, where it flies under the influence of the wind.
