The reform of the electric power industry in Russia led to the formation of such a specific product as electricity. Electricity does not have such a basic property inherent in other goods as accumulation and the ability to meet growing demand with reserves. The division of the market into wholesale and retail led to the need to create a competitive environment between manufacturers in the wholesale market. In the process of reforming the electric power industry, the market is gradually going through stages of transition from regulated to deregulated, based on natural competition between electricity producers.
2) The specifics of electricity as a product.
The most important features of the economics of energy systems, caused by the specifics of electricity as a commodity and which must be taken into account when organizing the electricity market, are the following: 1) production, delivery (transmission and distribution) and consumption of electricity due to its physical nature occur almost simultaneously and it is impossible to store (accumulate) ) in significant quantities. In other words, manufactured products cannot accumulate in the warehouses of the manufacturer, consumer, or on the way, but are almost instantly delivered to the consumer and consumed by him; 2) electricity is a highly standardized product, supplied by many producers into a “common pot” (i.e., into common electrical networks) and instantly consumed from there by many consumers. Therefore, from a physical point of view, it is impossible to determine who produced the electricity consumed by a particular consumer - you can only control the volumes of supply to the common network from each manufacturer and the volumes of consumption from it by each consumer; 3) electricity received by the consumer from the energy system is an essential commodity, which only in rare cases has other substitute goods (for example, the transition to electricity supply from an autonomous diesel power plant, the transfer of electric heating to gas heating and some other cases). For this reason, consumers are usually extremely sensitive to power outages, and the power system must have the necessary margin of reliability. In passing, we note that possible forced shutdowns of some consumers in conditions of electricity shortages or accidents lead to a decrease in consumption, but not demand. In other words, demand in the electricity market does not always equal consumption; 4) producers generate and supply electrical power to the common network exactly in accordance with their obligations (or the dispatcher’s assignment), and all consumers consume electrical power in total exactly in accordance with their obligations (or the dispatcher’s forecast). But in practice, due to a variety of circumstances, both producers and consumers allow deviations from their obligations. This entails an imbalance between supply and consumption. In any other market, a short-term imbalance between the production and consumption of a product does not lead to a loss of market stability; it is easily eliminated through inventory or substitute goods. The specificity of electricity as a commodity leads to the development of an electricity market that is different from conventional commodity markets.
How energy storage technologies will change the world
Text: Andrey VELESYUK
Last year, billionaire Elon Musk once again excited the public: his company built and prepared for operation an electricity storage facility with a total capacity of 100 MW in 100 days. This has intensified the debate about energy storage technologies and the changes their development could bring. We decided to figure out how Russia is preparing for the coming changes and what exactly should be expected.
Photo: Flickr.com, Flickr/U.S. Department of Energy, Siemens.com, Rosatom,
Newsroom.ucla.edu
General state of affairs
Last August, the Ministry of Energy published the “Concept for the development of the market for electricity storage systems in the Russian Federation.”
Russia, with a significant lag, is beginning to form a national industry for energy storage systems and develop a market for the use of these systems in various sectors of the economy. For example, in the United States, the California Energy Storage Mandate program was launched in 2010, according to which the country will have 1,325 MW of storage capacity by 2020. The UK and China became concerned with this issue in 2016: the former acquired 201 MW of storage systems, the latter plans to build storage systems with a capacity of 46 GW by 2021. And last year, the media circulated a story, the main character of which was, again, Elon Musk: in Australia, the world’s largest lithium-ion battery system was built in 100 days (See reference).
The authors of the Russian “Concept” listed the main events in the market for electricity storage systems that are already taking place in the country: “many startups have been created,” specialized conferences are being held, the Ministry of Education and Science has allocated 1.3 billion rubles over three years. for relevant R&D, there are innovative development programs. From all this, a conclusion has been drawn: in Russia, scattered and uncoordinated actions are still being carried out, which do not ensure the achievement of a breakthrough effect in the development of the industry and market of electricity storage systems.
- “Internet of Energy” - the use of electricity storage systems as part of the distribution energy sector;
- “new general scheme” - the use of electricity storage systems as part of large centralized energy;
- “hydrogen energy” - the use of electricity storage systems in the hydrogen cycle for energy with high requirements for autonomy, mobility, and environmental friendliness.
The authors of the document claim that by 2025, the global market for electricity storage systems will be about $80 billion. In an optimistic scenario, the Russian market for these systems will reach about $8 billion per year by that time, and the total economic effect, excluding investments and taking into account exports (electricity and hydrogen fuel storage systems) will be about $10 billion per year.
$25 million dispute
The renewable energy-dependent Australian state of South Australia is home to 1.7 million people; they regularly had problems with energy supply. There was not enough storage across the state to supply more power during peak demand. Last March, Tesla founder and CEO Elon Musk promised to solve this problem.
The billionaire tweeted that he was ready to ensure uninterrupted supply of electricity to the state of South Australia within 100 days. He promised to install a battery system there with a total capacity of 100 MW, which would cost $25 million before installation costs and taxes. If the company had not managed to do this in 100 days, customers would not have paid Tesla a dime.
In July, Elon Musk announced that he had received approval from Australian authorities to build the world's largest lithium-ion battery system there. The electricity storage station was connected to a wind farm in Jamestown, owned by Neoen. The total power of the battery system was 100 MW, capacity - 129 MWh.
In November, Tesla reported the completion of work on the installation of a system of ultra-high-capacity Powerpack batteries with an output power of 100 MW. However, at the same time, Mashable discovered that by the time work officially started, the system was already operating at half of its designed capacity - 50 MW. That is, formally the condition was met, but Musk hedged his bets by starting to build the station before official approval.
However, the Neoen company, which earned $800 thousand (Australian) from these batteries in two days, did not become indignant.
Storage technologies will change the energy landscape
VYGON Consulting consultants are confident that the development of energy storage systems will play a key role in increasing the share of generation facilities based on renewable energy sources (RES).
Although in developed countries this segment is already growing quite quickly: in 2017 in Germany, 36.1% of electricity was generated from renewable energy sources (3.8% more than a year earlier). In Denmark, more than 40% of the national electricity demand is met using such sources.
It is also worth considering that, according to the International Energy Agency (IEA), in the next 25 years, more than a third of the world's operating capacities (2.3 thousand GW) will reach their age limit and will be decommissioned. And most likely, in the event of a significant reduction in the cost of energy storage technologies, all these power plants will be replaced by distributed renewable energy generating facilities. But so far everything comes down to the high cost of solutions.
VYGON Consulting experts also believe that in the near future, a breakthrough will be the achievement of network parity between energy storage technologies and renewable energy generation in island and autonomous systems that do not have significant reserve safety margins. Vivid examples of such territories are isolated regions of the Far North and Far East of Russia. They can become pilot regions for the experimental and industrial application of hybrid energy supply solutions based on renewable energy generating capacities in combination with storage systems.
Deputy Chairman of the Board of Management Company RUSNANO Yuri Udaltsov also believes that the emergence of a large number of storage devices will fundamentally change the energy system. Now, to regulate the frequency, the dispatcher reserves a large reserve of power to cover peaks in certain hours. As a result, stations are on average less loaded than they could be. With the advent of industrial storage systems, production and consumption schedules can be separated and made convenient for each party. This will fundamentally change the markets for electricity and power engineering, focused on agility. If there is no need for it, it is enough to put the nuclear power plant in the basic operating mode and not maintain “spare” capacities. Yu. Udaltsov noted, however, that this will become possible no earlier than in 20 years.
Another trend in the changing energy landscape concerns electricity consumption, in particular, the rapidly growing smart home segment. We are talking about housing in which the control of life support systems is as automated as possible. According to a report by the marketing company Zion Market, the global market for smart housing solutions is now $246 billion and until 2022 its average annual revenue growth rate will be 17.5%. IDC analysts, in turn, claim that last year 433.1 million devices related to the “smart home” system were sold worldwide, and in the next five years the average annual growth rate will be approximately 18.5%. That is, by 2022 there will already be 939.7 million similar devices in the world. In the “Digital Economy of the Russian Federation” program, the creation of “smart cities” consisting of “smart houses” is named one of the key areas.
The peculiarity of the energy supply of a “smart home” is that due to connected video devices, security systems, smoke detectors, “smart” lighting devices, etc., it becomes very energy-intensive. If the safety of the home depends on the energy supply, the reliability and uninterrupted operation of the equipment is very important to the consumer. Increasingly, owners of “smart homes” use autonomous generators and uninterruptible power supplies (UPS), to which they connect the most important systems: lighting, warning and fire safety. Thus, we are observing the active development of the distribution energy segment.
Why aren't batteries used everywhere?
The first clear energy storage technology appeared at the end of the 19th century - pumped storage power plants. During periods of low demand for electricity (for example, at night), pumped storage power plants consume it to collect water into the upper reservoir. And at times of peak loads (for example, in the morning hours in a metropolis), electricity is produced due to the sudden release of water.
In Russia, the only operating station of this type is the Zagorskaya PSPP in the Moscow region. It helps cover the peak electricity consumption of the capital region.
Today, the total capacity of various types of energy storage systems in the world is approximately 150 GW. The overwhelming share of storage systems (97%) falls on pumped storage power plants, and $7-10 billion is invested annually in the construction of new pumped storage power plants. Leaders in installed capacity of pumped storage power plants: China (31,999 MW, 34 pumped storage power plants), Japan (28,252 MW, 43 pumped storage power plants ) and the USA (22,561 MW, 38 pumped storage power plants). Other storage options include compressed air systems, sodium sulfide and lithium batteries.
As for rechargeable batteries, experts estimate the costs of their installation in the range of $200-800 per 1 kW of installed power. Lead-acid batteries have the lowest costs. The main disadvantage of rechargeable batteries is their low life expectancy compared to pumped storage power plants. Battery life can vary quite a bit depending on frequency of use, discharge rate, and number of deep discharge cycles.
Electricity storage systems have another non-obvious side, in addition to financial and technological ones, - this is a moral aspect. The fact is that cobalt is used to produce batteries and rechargeable batteries, on which all modern equipment runs. Every year, approximately 120 thousand tons of cobalt are mined in the world, and 60% of its production occurs in the Democratic Republic of the Congo. For comparison: Canada accounts for 6% of production, Australia - 4%, Russia - 3%. Cobalt prices are rising rapidly, and this is stimulating the growth of its production in the Congo.
According to UNICEF data cited by the online publication Meduza, in 2014, out of 150 thousand local miners, about 40 thousand were children. Moreover, after cobalt began to rise in price, there were more children in the mines, Amnesty International believes. Some of them are not older than four years. A child's working day lasts an average of 12 hours, and daily earnings fluctuate around $1-2.
However, experts believe that it is possible to avoid rising cobalt prices and reduce the volume of its consumption. One of the metals that can replace cobalt (or rather, reduce its share in batteries to 10% from the current 50%) is nickel. There are more reserves of it in the world, it is more evenly distributed between countries and therefore cheaper. In this case, it will be possible to solve the moral problem.
Alternative to lithium-ion batteries
Sony released the first lithium-ion batteries in 1991. Since then, their capacity has almost doubled: 110 Wh/kg became 200 Wh/kg; They still rule the battery world, but scientists are actively working on new energy storage technologies. Here are the most interesting of them.
Sodium-ion batteries. In such batteries, sodium is used as ions moving between the electrodes. Given their low cost, the main disadvantage of such batteries is their small capacity. Scientists at Stanford University have developed a new sodium cathode that allows for increased capacity. Despite the fact that so far only initial tests have been completed, in the future scientists plan to optimize the material and structure of the anode to create a full-fledged efficient battery.
Aluminum based batteries. A group of researchers from the same Stanford University has been working for several years on an inexpensive solution that would allow the accumulation and storage of solar energy. The battery consists of an aluminum anode and a graphite cathode immersed in an electrolyte. For the latter, we have settled on urea, a chemical compound that is actively used as a fertilizer.
This battery is fully charged in 45 minutes and does not burn, unlike lithium-ion batteries. Scientists are now working on a commercial version of the battery, primarily to extend its service life - the current version can only withstand 1,500 cycles.
Organic fast-charging batteries. Israeli startup StoreDot last year introduced a battery for electric vehicles, developed based on its own technologies. They use layers of nanomaterials and organic compounds that the company says have never been used in batteries before.
The result is a battery that charges in 5 minutes and can travel 300 miles on a charge. StoreDot CEO Doron Myersdorf says such charging will help grow the popularity of electric vehicles. Firstly, because of the charging speed. Secondly, because FlashBattery is safer than lithium-ion batteries - it can withstand higher temperatures and does not burn.
Solid state batteries. Last year, Toyota announced a breakthrough in its own production. By 2020, the auto giant plans to begin production of all-solid-state lithium batteries, inside of which there is a liquid or gel electrolyte. They will be denser, smaller and lighter than the current ones. Another plus is the long service life.
Super- and ultracapacitors. These are hybrids of a capacitor (an electronic component capable of storing and releasing electrical charge) and a chemical current source (battery or accumulator). Compared to lithium-ion batteries, supercapacitors have higher charging and discharging rates and longer service life.
In an interview with EnergyLand.info, the head of the Kongran project, Semyon Chervonobrodov, said that his group managed to create prototypes of two electrical energy storage devices, fundamentally different in physical principles of operation. The first is a supercapacitor with a high specific capacity for this type of energy storage device. The second is a lithium-ion hybrid supercapacitor with a fundamentally new cathode. A new, environmentally friendly electrolyte based on polyamino acids has also been created.
He considers the transport industry to be the main area of application for supercapacitors. Work is currently underway to reduce the cost of production.
Construction of storage stations is inevitable
In the modern world, there is an obvious trend towards the gradual withdrawal of coal-fired generation without CO2 capture and storage facilities. According to forecasts, by 2030, 2/3 of the existing generation capacity will be decommissioned. Instead, a number of countries are switching to renewable energy sources.
Integration of unstable renewable energy sources into the energy system leads to a reduction in emissions, but raises the question of increasing the flexibility of the energy system.
At the same time, the demand for electricity is growing rapidly, including due to the development of smart home technologies. In the coming years, millions of additional devices will be connected to the Internet. For example, IDC analysts claim that last year, 433.1 million devices related to the “smart housing” system, such as smoke detectors, alarms, and video surveillance systems, were sold worldwide last year; over the next five years, the average annual sales growth rate will be approximately 18.5%. That is, by 2022 there will already be 939.7 million devices of this kind in the world. All this cannot but affect various aspects of the functioning of the energy sector, and first of all, the volume of its consumption and storage methods.
In connection with all these changes in a number of countries, plans for the development of renewable energy sources already include the need to build pumped storage stations, for example, in Indonesia (3 GW by 2025) and in Spain (8.8 GW by 2020). And in California, energy storage policy was established by the state legislature in 2010 and requires utilities and other utilities to plan for storage procurement.
The main growth in the volume of energy storage devices, according to expert forecasts, in the coming years will be achieved through the integration of renewable energy sources using lithium-ion batteries. Annual revenue from such batteries is expected to rise to $18 billion by 2023. Although pumped storage, the largest energy storage system available, is expected to remain the leader among system-wide energy storage systems for some time to come.
How is Russia going to participate in this global trend? No answer yet. There are few departmental concepts for real market development. We are preparing an overview of the situation within the country regarding the development of energy storage technologies and demand prospects. Look for it in one of the upcoming issues of the magazine.
How the world saves electricity
Irish-German hybrids
The Irish authorities plan to ensure that by 2020, 40% of the country's energy balance is provided by renewable energy sources; by 2035 they want to increase this figure to 100%. Most of this electricity comes from large wind farms.
To stabilize the system, German company Freqcon GmbH in South Dublin commissioned an energy storage system integrated with Maxwell ultracapacitors and lithium-ion batteries for the Tallaght Smart Grid Testbed in 2016. The UltraBattery lithium-ion battery is a hybrid of a chemical battery and an ultracapacitor. Battery supplier Ecoult says the invention is safe, sustainable, reliable and recyclable. The system has an installed power of 300 kW and a capacity of 150 kWh.
It is designed primarily to demonstrate the operation of a system for supporting the stability of the distribution network and solving problems associated with the irregularity of electricity production at power plants powered by renewable energy sources.
If the system shows its viability, it will be rolled out throughout Dublin and eventually throughout Ireland.
Dutch battery cars
In April of this year, Mitsubishi announced a joint project with Hitachi and Engie, which will allow the use of electric vehicles as renewable energy storage for buildings.
Test work will be carried out in the Engie office building located in the Dutch city of Zaandam. There, Hitachi installed its V2X bidirectional charger, capable of sending power back to the grid.
The charger is connected to the building's power supply, which in turn is equipped with solar panels. Since batteries often generate excess electricity, this will be stored in the electric vehicle's battery. In the event of a power outage, these vehicles will act as emergency power. The company will use the Mitsubishi Outlander electric vehicle (PHEV) as the battery.
If the experiment turns out to be successful, the line of electric vehicles that can participate in the creation of similar energy regulation systems is promised to be expanded. British energy company Moixa claims that just ten new Nissan LEAFs can store enough energy to power an hour's worth of the typical electricity consumption of a thousand homes.
Renault specialists were the first to announce such a use of electric vehicles: they promised to create an intelligent electric ecosystem in the Portuguese islands of Madeira, in which batteries would be used as stationary energy storage.
Ultracapacitors from San Diego
Since 2016, the UC San Diego campus has been powered by a microenergy system with a peak power of 42 MW.
45 thousand people live on campus - like in a small city. 85% of consumption is covered by own generation, including a combined cycle plant (30 MW), a fuel cell station (2.8 MW), and a solar photovoltaic station (2.2 MW).
The storage system is organized from standard lithium-ion storage units and ultracapacitors. The goal of the project is to verify that ultracapacitors can provide a more cost-effective energy storage system and better response time than batteries.
As we have already said, in ultra- or supercapacitors, charges are separated electrostatically, and not chemically. This allows ultracapacitors to charge and discharge in fractions of a second, function normally in a wide temperature range (from -40 0C to +65 0C), reliably perform 1 million charge/discharge cycles and resist vibration. The capacitor bank is connected in parallel to the car battery. The parallel circuit significantly increases the life of the battery, allowing it to have a lower capacity and therefore smaller dimensions.
Before the advent of ultracapacitors, this scheme was not feasible due to the large size of the capacitors. Now, if there is a sharp drop in power, the ultracapacitor modules support the system, and when solar energy increases, they charge. In this way, ultracapacitors perform fast functions such as frequency control, while batteries are used to shift demand peaks and provide operational reserve.
Y.N.ELDYSHEV The problem of energy storage is one of the most important not only in the energy sector, but also in the economy (as well as in science) in general. It has not yet been fully resolved. Our inability to effectively store and store the resulting energy has a particularly detrimental effect on the development of such relatively “clean” methods of its production using renewable energy sources, such as hydropower, solar power or wind power. After all, we are still not able to ensure a guaranteed supply of energy to consumers from such sources due to understandable daily, seasonal, and even poorly predictable changes in their power. Therefore, any information about achievements in this area is of great interest.
Methane project
A new method of storing energy obtained from renewable energy sources (one of the main disadvantages of which is the instability and unpredictability of energy production) was recently reported by the press service of the Fraunhofer Society (the Joseph Fraunhofer Society is the German analogue of the Russian Academy of Engineering Sciences, its main goal is to promote applied research). German scientists have developed a technology in which excess electricity generated by solar or wind power plants and not needed at the moment is converted into methane. The gas thus obtained can be stored indefinitely and used as needed using the existing gas infrastructure.
The pilot project, developed by the Center for Solar Energy and Hydrogen Research, which is located in Stuttgart (Germany), is currently being implemented by cooperating companies in Austria and Germany. The launch of an industrial station with a capacity of tens of megawatts based on this technology is planned for 2012.
According to the developers, the demonstration system, built in Stuttgart, uses excess energy generated by solar panels and wind power plants (WPP) for the electrolytic dissociation of water into oxygen and hydrogen. Subsequently, the resulting hydrogen, combining with carbon dioxide supplied to the system, forms methane, which can already be stored and used to generate energy at any time. According to scientists, the efficiency of such a transformation is above 60%.
It is no secret that “classical” methods of storing electricity in capacitors and batteries require the creation of a special (additional and quite expensive) infrastructure. In contrast to such methods for storing energy in the form of methane in Germany, as in many other countries, all the necessary infrastructure already exists - this is a distributed system of large-capacity gas storage facilities. Therefore, the authors of this technology believe that it may have good prospects, because such a transformation with decent efficiency is “definitely better than a complete loss of electricity that cannot be used here and now.” But to date, not many real alternatives to “gas conversion” as a method of energy storage have been proposed.
"Achilles' heel" of hydraulic accumulators
Pumped storage power plants can vary greatly in appearance: many storage stations are almost impossible to distinguish from a conventional hydroelectric power station located on a river with a significant slope, but there are also those that have a very unusual storage tank, such as the Taum Sauk station in the state Missouri (USA), attracting the attention of many tourists. But in any case, this method of storing and redistributing energy has a serious drawback - the need to alienate large areas for the upper and lower pools, as well as large-scale (and expensive) construction work.
Water alternative
One of the oldest energy storage devices is a pumped storage power plant (PSPP). This is the name of a type of hydroelectric power station specifically designed to level out the daily heterogeneity of the electrical load. PSPP uses a complex of electric generators and electric pumps or special reversible hydroelectric units that can operate both as generators and pumps. During the minimum energy consumption, the pumped storage power plant receives cheap electricity from the power grid and uses it to pump water to the upper pool, i.e. it acts as a pump. And during the morning and evening peaks in energy consumption, the pumped storage power plant discharges water from the upstream to the downstream, generating expensive “peak” electricity, which it sends to the power grid, i.e., it acts as an electric generator.
Since in both modes the efficiency of such a plant is less than 100%, it is clear that in the end the pumped storage power plant consumes more electricity than it produces, i.e. formally it turns out to be unprofitable. However, we should not forget that pumped storage power plants consume “cheap” energy and supply “expensive” energy to the network, so the economic result does not coincide with the energy balance and is not determined by simple arithmetic operations. The fact is that in large energy systems a significant share is made up of the capacity of thermal and nuclear power plants, which cannot quickly reduce electricity production when energy consumption falls or do so with large losses. That is why the commercial cost of electricity during the period of highest (“peak”) consumption in the energy system is much higher than during the period of its minimum consumption, and the use of pumped storage power plants turns out to be cost-effective, increasing both the uniformity of the load on other capacities of the energy system and the reliability of energy supply in general.
A pumped storage power plant looks like a simple and reliable energy storage system, which has many advantages and only one, but very significant, weakness: it cannot be built everywhere, and it takes up a lot of space.
Energy can be stored... in the refrigerator
More recently, it was proposed to store “wind energy” (electricity obtained from wind turbines) by changing the temperature in huge cold storage warehouses, which requires almost no capital expenditure. A group of researchers from universities in Bulgaria, Denmark, Spain and the Netherlands developed the Night Wind project, aimed at creating a pan-European wind energy storage system based on the use of elements of existing infrastructure.
The idea is simple: at night, when electricity consumption drops, but wind turbines continue to operate, the electricity they generate is proposed to be used to lower the temperature in the existing refrigerators of large food warehouses. Estimates have shown that it is enough to reduce the temperature by just 1 °C compared to the usual norm. In other words, energy will be “stored” as a result of the cooling of many thousands of tons of various products, which will be stored as usual somewhere in Denmark, Holland or France. During the day, when electricity consumption increases many times over, all these giant refrigerators can simply be unplugged from the network until the temperature in them gradually rises by the same 1 °C, i.e., returns to its usual value.
And although, as is well known, refrigerators themselves, even the most gigantic ones, of course, do not produce any electricity, such temperature fluctuations are only one degree with a period of a day, if they are applied to all large refrigerated warehouses in Europe, according to estimates from the authors of the project , will be equivalent to the appearance of a superbattery with a capacity of 50 GWh in the general energy grid!
The authors of the project demonstrated the effectiveness of the idea back in 2007 by installing a wind turbine next to one of the largest refrigerated warehouses in Bergen (Netherlands) and setting up an electronic refrigerator control system according to the principle described above. So now the fate of the project is in the hands of energy economists, who must decide how advisable it is to rely on this particular method of storing energy.
Flywheels
Many experts still consider flywheels to be a very promising energy storage device. Discussions about them have been going on for decades. But only recently have truly workable projects been developed that demonstrate the capabilities of such drives in practice.
Back in 1964, Professor N.V. Gulia (lately the head of the department at Moscow State Industrial University) proposed a new type of flywheel, which was supposed to serve as an energy storage device. It was not a solid disk, but a core with hundreds and even thousands of layers of thin steel (later plastic) tape wound around it, enclosed in a casing, inside of which a vacuum was created to reduce friction losses. As it turned out, such superflywheels could “absorb” quite a lot of energy per unit mass, because the energy they stored was determined primarily by the maximum rotation speed (since it was proportional to its square and depended linearly on the mass), which in turn was limited by the strength of the chosen material.
Modern superflywheels with carbon fiber winding have a specific energy content of up to 130 Wh/kg. This is somewhat inferior to the performance of the best lithium-ion batteries, but flywheel drives also have their advantages: they are much cheaper, more durable and safer (not only for the health of operating personnel, but also, just as important, for the environment).
The inventor himself experimented a lot with superflywheels 40 years ago, because he considered them promising energy storage devices for transport and even built several samples of such vehicles. He also thought about their use in the energy sector as an alternative to batteries, but until recently the idea of using flywheels to store energy not in laboratories, but on an industrial scale and in existing energy networks seemed exotic and even utopian to specialists. Only in recent years have some companies in the West begun serious research in this area.
Thus, specialists from the American company Beacon Power have developed a set of stationary superflywheels designed for connection to industrial power grids. They are made from a huge number of layers of ultra-strong composite materials based on carbon fibers, so that they can withstand enormous loads, allowing their rotation speed to be increased to the standard 22.5 thousand rpm in a high vacuum environment. Flywheels on magnetic suspensions rotate in cylindrical containers about 1 m high (new models will be taller than a person), inside of which a vacuum is created. The weight of such a structure can reach 1 ton.
On the steel shaft of the flywheel (in the same place - inside a sealed steel cylindrical casing) there is a rotor of a reversible electric machine - a permanent magnet motor-generator, which spins the flywheel, storing energy, or releases it, generating electric current, when a load is connected.
The estimated service life of such a design is 20 years, the operating temperature range is from -40 to +50 ° C, it can withstand earthquakes with a magnitude of up to 7.6 on the Richter scale, in other words, it has characteristics that are now completely unrealistic for existing chemical batteries.
Air will save energy
The American company Magnum Energy NS is going to use underground caves at a depth of about 1.5 km to store liquefied air used to generate electricity. It is planned to create storage facilities near the city of Delta in Utah, where there are huge underground reserves of salt, which they hope to wash out using special equipment. At the first stage, it is planned to equip storage facilities for natural gas produced nearby - in the Rocky Mountains. Having perfected the technology, the company intends to begin creating storage... for air.
According to the authors of this project, air compression can be considered one of the cheapest ways to store energy. For example, on a clear day, a solar power plant will produce excess electricity. It will be sent for compression and air injection. When electricity is needed, the air will be forced to spin turbines. In this way, the authors hope to overcome the main difficulty in the widespread introduction of renewable energy sources - the instability of their electricity production and, accordingly, the problem of storing and converting energy from them.
However, so far the amount of energy stored in this way is small - up to 25 kW/h with a maximum power of up to 200 kW. According to the developers' estimates, the loss of energy stored and withdrawn from such storage devices does not exceed 2%, which is much better than that of energy storage systems based on other principles (mentioned pumped storage power plants, chemical batteries, etc.). At the same time, it is clear that the energy storage period in flywheels, unlike these systems, is short - for now we can only talk about their use as a buffer, compensating for sharp peaks and declines in electricity consumption during the day.
Sets of many such devices connected in parallel could accumulate quite noticeable reserves of energy; in this case, the main advantage would be that this would happen very quickly (it would be possible to “claim” what had been accumulated just as quickly). But this is very important. The fact is that any of the existing industrial generating capacities (for example, at thermal power plants) cannot quickly respond to changes in load, and in general any changes in their operating modes are extremely unprofitable.
It is in such situations, associated with sudden surges in the load on the network, that drives in the form of flywheels could become a completely reasonable solution. According to the developers, the response time of such systems is simply fantastic - about 5 ms.
Installations with such storage devices have already demonstrated their effectiveness in tests in a number of US communities, whose residents have not yet forgotten the nightmare of their de-energized cities due to a chain power outage and are ready to do anything to reduce the likelihood of such events reoccurring.
However, it seems that the Russian energy system, which, due to a number of features, is noticeably more resistant to load fluctuations than the US energy network, could benefit from such storage devices.
Invention... blades
An interesting way to smooth out the unevenness of electricity generation from wind turbines was found by Professor of the University of Nottingham (UK) Seamus Garvey, who concluded that wind turbines located in the open sea should not be equipped with electric generators at all, since such powerful devices that generate current even at the lowest shaft rotation speeds turn out to be very heavy and, accordingly, very expensive. Instead, he proposes making windmill blades... hollow. A heavy piston must move freely inside each of them. When the blade descends, the piston moves towards its end, and when it rises, the piston, on the contrary, slides towards the axis, compressing the air entering through the holes in the housing. Compressed air is pumped into special bags made of thin and durable synthetic fabric, floating at a depth of 500 m!
These storage facilities, kept from bursting by the pressure of the overlying water layers, serve as a kind of buffers that guarantee uniform power generation even in unpredictable wind conditions. From underwater cylinders, air is supplied through pipes to additional compact turbine generators. It is estimated that its reserve should be enough to maintain their rotation for several days, even in complete calm.
This “Integrated Compressed Air Renewable Energy Systems” (ICARES) is impressive in its scale: Harvey estimates that the turbine would have to move slowly and be very large to keep the pistons from hanging at the ends of the blades due to centrifugal forces. over 200 m in diameter (ideally 500 m). As for underwater energy storage facilities, the author sees them as gigantic clusters of huge air “cushions” (20 m in diameter).
Work on the project has been ongoing since 2006, and now the university has created the Nimrod Energy company, whose main task will be the commercialization of this technology. It is expected that ICARES systems will appear on the market within a year. But at first they will be used to store energy generated by other types of power plants. And giant offshore turbines from Nimrod, according to the developers’ forecasts, may appear in 10-15 years.
Unusual battery and some other methods
Today, quite high activity in the West is also associated with projects for storing electricity generated, in particular, by wind turbines that are very popular here, in the form of hydrogen obtained with its help. Moreover, in such projects it is proposed to use hydrogen not as fuel, but as a temporary energy carrier. However, according to experts, such schemes, which can be very efficient from an energy point of view and quite acceptable from an environmental point of view, alas, still remain too expensive.
Research continues on various technologies for pumping compressed air into underground or underwater storage facilities.
But, as already noted, each of the mentioned methods of energy storage has its own advantages and disadvantages, each of them is good in its own way, but none can be considered ideal. In this regard, recently there have even been calls to return to chemical batteries that seemed to have been thoroughly studied a long time ago. However, not quite ordinary - molten.
In fact, the so-called hot batteries were also invented many years ago. There are many varieties of them that have enviable specific characteristics. But it is not easy to ensure the operating temperature required for them, hundreds of degrees Celsius, so this condition imposes serious restrictions on the possible areas of their application, as well as on their possible lifespan (all previous proposals to use such batteries on a large scale turned out to be uncompetitive due to for the extremely short period of their validity). However, in the Japanese prefecture of Aomori, for example, a complex of 17 large blocks of sulfur-sodium hot batteries with a capacity of 34 MW, which are connected to the network through AC/DC converters, has been operating for several years. This complex is part of the new Futamata wind farm, significantly smoothing out the unevenness of wind turbine electricity production (allowing it to satisfy the daily peak of consumption and accumulating energy at night).
But the new battery, the prototype of which was created by American scientists, according to their estimates, will be three times cheaper than today’s best batteries, much more durable and, most importantly, much more powerful. Professor Donald Sadoway and his colleagues from the Massachusetts Institute of Technology have come up with an original device for accumulating electrical energy, which, in their opinion, will in the near future make it possible to use energy obtained from solar panels (or wind energy in calm weather) at night. Such a battery, the size of a garbage container familiar to Americans in an individual home (its volume is about 150 liters), according to Sadoway, could become an integral attribute of a “green” home, providing all its energy needs even at the peak of consumption, and would be recharged it comes from “intermittent” wind turbines and solar panels. Well, large sets of such batteries, according to the developers, would be quite capable of supplying electricity to entire settlements - a storage station with a capacity of 13 GW (enough to power a large city) would occupy only 6 hectares.
How is this power density achieved? The fact is that, as the developers assure, these batteries are capable of delivering and receiving 10 times more current than all known types of chemical batteries.
Realizing that too much current could easily damage the device, simply melting the entire structure, Sadoway suggested that a melted state be the norm for all parts of the battery. In previous hot batteries, in addition to cases and contacts, there was another important solid (unmelted) element - solid electrolyte (special conductive ceramics), but in the new battery there are no solid parts inside at all, except for the outer case, everything is liquid - both the electrolyte and the electrodes. All elements of the new unusual system do not mix with each other due to different densities, just as oil and water do not mix in a vessel at rest. And since the new battery is designed to become a stationary energy storage device, there seems to be no reason for the liquids to mix.
The developed battery resembles a refractory “glass” (the body serves as the first external contact), covered with a lid (the second external contact). Between them there is a dielectric, and around there is a heat-insulating shell. The authors placed antimony at the bottom of the container (this is the first internal electrode), followed by sodium sulfide (electrolyte), and magnesium on top (the second internal electrode). All components are in molten form.
When charging, the electrolyte layer in such a battery becomes thinner, and the molten electrodes become thicker. During a discharge, everything happens in the reverse order: the material of the electrodes (ions) partially transforms into the electrolyte, so that the central liquid layer grows, and the side electrodes contract.
Such a system, which uses a rather unusual operating principle and design for chemical batteries, as it turned out, is capable of withstanding a huge number of charge and discharge cycles, many times greater than anything that previous batteries could demonstrate, and in addition, can give and receive gigantic currents without any damage (there is simply nothing in the system that can fail). Finally, all the components of such a battery turned out to be surprisingly inexpensive, so such systems can be installed anywhere.
The authors built a prototype molten battery. Its specific capacity is not very impressive yet. But this is not so critical - for a stationary energy storage device, the mass of the system is not very important. In addition, scientists believe that all the characteristics of the new battery can be seriously improved by maintaining the principle of operation, but selecting other components.
The developers promise to bring the created prototype to a commercial version in five years. And this is quite fast, considering that hot batteries of the previous types, although they were invented a very long time ago, are still considered exotic despite all attempts to improve them.
Based on materials from sciencedaily.com, physorg.com, membrane.ru and other sources
Electric power industry is one of the few areas in which there is no large-scale storage of produced “products”. Industrial energy storage and production of various types of storage devices is the next step in the large electric power industry. Now this task is especially acute - along with the rapid development of renewable energy sources. Despite the undeniable advantages of renewable energy sources, one important issue remains that must be resolved before the widespread introduction and use of alternative energy sources. Although wind and solar energy are environmentally friendly, their generation is intermittent and requires energy storage for later use. For many countries, a particularly urgent task would be to obtain seasonal energy storage technologies - due to large fluctuations in energy consumption. Ars Technica has prepared a list of the best energy storage technologies, and we will talk about some of them.
Hydraulic accumulators
The oldest, most mature and widespread technology for storing energy in large volumes. The principle of operation of the hydraulic accumulator is as follows: there are two water tanks - one is located above the other. When the demand for electricity is low, the energy is used to pump water into the upper reservoir. During peak hours of electricity consumption, water is drained down to a hydrogenerator installed there, the water spins a turbine and generates electricity.
In the future, Germany plans to use old coal mines to create pumped storage tanks, and German researchers are working on creating giant concrete hydrostorage spheres placed on the ocean floor. In Russia there is the Zagorskaya PSPP, located on the Kunya River near the village of Bogorodskoye in the Sergiev Posad district of the Moscow region. Zagorskaya PSPP is an important infrastructural element of the center's energy system, participating in the automatic regulation of frequency and power flows, as well as covering daily peak loads.
As Igor Ryapin, head of the department of the Association "Community of Energy Consumers" said at the conference "New Energy": Internet of Energy, organized by the Energy Center of the Skolkovo Business School, the installed capacity of all hydraulic accumulators in the world is about 140 GW, to the advantages of this technology include a large number of cycles and a long operating life, efficiency of about 75-85%. However, the installation of hydraulic accumulators requires special geographical conditions and is expensive.
Compressed air energy storage devices
This method of energy storage is similar in principle to hydrogeneration - however, instead of water, air is pumped into the reservoirs. Using a motor (electric or other), air is pumped into the storage tank. To generate energy, compressed air is released and rotates the turbine.
The disadvantage of this type of storage device is low efficiency due to the fact that part of the energy during gas compression is converted into thermal form. The efficiency is no more than 55%; for rational use, the drive requires a lot of cheap electricity, so at the moment the technology is used mainly for experimental purposes, the total installed capacity in the world does not exceed 400 MW.
Molten salt for solar energy storage
Molten salt retains heat for a long time, so it is placed in solar thermal plants, where hundreds of heliostats (large mirrors concentrated on the sun) collect the heat from sunlight and heat the liquid inside - in the form of molten salt. Then it is sent to the tank, then, through a steam generator, it rotates the turbine, which generates electricity. One of the advantages is that molten salt operates at a high temperature - more than 500 degrees Celsius, which contributes to the efficient operation of the steam turbine.
This technology helps extend working hours, or heat rooms and provide electricity in the evening.
Similar technologies are used in the Mohammed bin Rashid Al Maktoum Solar Park - the world's largest network of solar power plants, united in a single space in Dubai.
Flow redox systems
Flow batteries are a huge container of electrolyte that is passed through a membrane and creates an electrical charge. The electrolyte can be vanadium, as well as solutions of zinc, chlorine or salt water. They are reliable, easy to use, and have a long service life.
There are no commercial projects yet, the total installed capacity is 320 MW, mainly within the framework of research projects. The main advantage is that it is so far the only battery technology with long-term energy output - more than 4 hours. Disadvantages include bulkiness and lack of recycling technology, which is a common problem with all batteries.
German power plant EWE plans to build the world's largest 700 MWh flow battery in Germany in caves where natural gas was previously stored, Clean Technica reports.
Traditional batteries
These are batteries similar to those that power laptops and smartphones, but in industrial size. Tesla supplies such batteries for wind and solar power plants, and Daimler uses old car batteries for this.
Thermal storage
A modern home needs to be cooled - especially in hot climates. Thermal storage facilities allow water stored in tanks to be frozen overnight; during the day, the ice melts and cools the house, without the usual expensive air conditioning and unnecessary energy costs.
The California company Ice Energy has developed several similar projects. Their idea is that ice is produced only during off-peak power grid periods, and then, instead of wasting additional electricity, the ice is used to cool rooms.
Ice Energy is collaborating with Australian firms that are looking to bring ice battery technology to the market. In Australia, due to the active sun, the use of solar panels is developed. The combination of sun and ice will increase the overall energy efficiency and environmental friendliness of homes.
Flywheel
The superflywheel is an inertial accumulator. The kinetic energy of motion stored in it can be converted into electricity using a dynamo. When the need for electricity arises, the structure generates electrical energy by slowing down the flywheel.
Wikimedia Commons
Perhaps the oldest form of modern grid-tied energy storage. The principle of operation is simple: there are two water tanks, one higher than the other. When electricity demand is low, the energy can be used to pump water upward. During peak hours, water rushes down, spinning a hydro generator and generating electricity. Similar projects are being developed, for example, by Germany in abandoned coal mines or spherical containers on the ocean floor.
Compressed air
Power South
In general, this method resembles the previous one, except that instead of water, air is pumped into the tanks. When necessary, air is released and rotates the turbines. This technology has existed in theory for several decades, but in practice, due to its high cost, there are only a few working systems and a few more test ones. Canadian company Hydrostor is developing a large adiabatic compressor in Ontario and Aruba.
Molten salt
SolarReserve
Solar energy can be used to heat salt to the desired temperature. The resulting steam is either immediately converted into electricity by a generator, or stored for several hours as molten salt to, for example, heat homes in the evening. One of such projects is the Mohammed bin Rashid Al Maktoum solar park in the United Arab Emirates. And in the Alphabet X laboratory, it is possible to use molten salts in combination with antifreeze in order to preserve excess solar or wind energy. Georgia Tech recently built a more efficient system that replaces salt with liquid metal.
Flow batteries
CERN scientists: “The universe should not exist”
Redox flow batteries consist of huge tanks of electrolyte that are passed through membranes and create an electrical charge. Typically, vanadium is used as an electrolyte, as well as solutions of zinc, chlorine or salt water. They are reliable, easy to use, and have a long service life. The world's largest flow battery will be built in caves in Germany.
Traditional batteries
SDG&E
Calmac
At night, the water stored in the tanks is frozen, and during the day the ice melts and cools neighboring houses, allowing you to save on air conditioning. This technology is attractive for regions with hot climates and cool nights, such as California. In May of this year, NRG Energy delivered 1,800 industrial ice batteries to Southern California Edison.
Super flywheel
Beacon Power
This technology is designed to store kinetic energy. Electricity starts the motor, which stores rotational energy in the drum. When needed, the flywheel slows down. The invention is not widely used, although it can be used to ensure uninterruptible power supply.
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