In recent years, China has accelerated the development and utilization of renewable energy. However, for the power grid, wind power and photovoltaic used to be a "troublesome" energy source. Due to the characteristics of wind power and photovoltaic power generation, when "extremely hot and windless" and "extremely cold and no light", it is easy to cause fluctuations in electricity.
In the first half of this year, China's total installed capacity of renewable energy historically exceeded that of traditional coal-fired power plants. From January to October this year, the new installed capacity of renewable energy such as hydropower, wind power and photovoltaic power generation hit a record high, accounting for 76% of the country's new power generation capacity. So, what makes wind power and photovoltaic power from "troublesome electricity" to "hot electricity"?
How does the "Super Charger" work?Visit the largest pumped storage power station in Northeast China.
To solve the problem of large fluctuations in the power of wind power and photovoltaic power generation, the easiest way is to store these electricity with "power banks", and then discharge them stably. Recently, a "super charger" in Northeast China is about to be put into use, which is the largest pumped storage power station in Northeast China - Liaoning Qingyuan Pumped Storage Power Station. How does this "super charger" work?What's so special about it?
CCTV reporterZhang CongjingAt the Qingyuan Pumped Storage Power Station in Liaoning, a reservoir built in the mountains is the main part of the power station. When the floodgates have been opened, the water flows into another reservoir at the foot of the mountain, which looks like an ordinary release, but is actually generating electricity.
The pumped storage power station uses different terrain to build two reservoirs, and when the power is surplus, the water in the low place is pumped to the high place with low valley electric energy for energy storage, and then the water in the high place is put down to generate power and ensure supply during the peak of electricity consumption, which is equivalent to a "super charging treasure", which can realize the efficient conversion and utilization of energy.
Yao Baoyong, Chief Technologist of Beijing Survey, Design and Research Institute of PowerChina Group:Pumped storage power stations are generally composed of upper reservoirs, lower reservoirs, underground plants and water transmission systems. The difference between the upper and lower reservoirs of our power station is about 400 meters, and the huge difference in height makes the power generation and energy storage very efficient.
CCTV reporterZhang CongjingLocated more than 400 meters underground, the underground plant is equivalent to the "heart" of the power station, and there are many generator sets in it. The first unit that will soon be put into operation for power generation is undergoing power generation tests. After it is put into operation, it can generate 1.5 million kWh of electricity per day, which can meet the daily electricity consumption of 300,000 households. The secret of the "super charger" power generation lies in the fact that when the water flows down from the upper reservoir and hits the runner, it will drive the rotor to rotate at high speed, constantly cutting the magnetic inductance lines, thereby generating electricity.
Yao Baoyong, Chief Technologist of Beijing Survey, Design and Research Institute of PowerChina Group:The weight of the rotor of each unit of our unit is 430 tons, and nearly 40,000 parts need to be installed, and when the first unit (group) generates electricity, the rotor rotates at a high speed of 375 revolutions per minute, which is the main indicator of stability, and its average oscillation is only 005 mm, which is less than half the diameter of a hair. It can be said that it rotates at high speed without moving, which greatly reduces the adverse effects of vibration and noise.
The KingAgroot Pumped Storage Power Station is located deep in the mountains and has a fragile ecological environment. Therefore, the construction of the entire power station is designed with fair-faced concrete technology, and the main facilities such as the dam crest structure, hoist room, and underground plant are not decorated, which is low-carbon and environmentally friendly, and minimizes the impact on the ecological environment.
CCTV reporterZhang CongjingAnother big difference in the appearance of the power station is that there is a clear snow dividing line on the dam face, and the smooth dam surface can barely hold snow because of the anti-ice erosion material used on it. It is a very cold area, with a minimum temperature of nearly -40, so when it was built, the engineers tried to make it more frost-resistant.
Yao Baoyong, Chief Technologist of Beijing Survey, Design and Research Institute of PowerChina Group:We have adopted self-developed anti-freezing new materials, new structures and new equipment, such as flexible water-stopping materials for the structural joints of the concrete panel of the dam, as well as anti-icing cover devices in the reservoir area, which effectively solved the adverse effects of the low temperature environment in the severe cold area on the main buildings of the power station and improved the durability and safety of the project by more than 30%.
It is understood that the first capacity of Qingyuan pumped storage power station is 1.8 million kilowatts, with a designed annual power generation capacity of 3 billion kilowatt hours and an annual pumped hydropower capacity of 4 billion kilowatt hours. After the completion of the project, it will undertake tasks such as peak regulation, valley filling and frequency regulation in the power grid, and will save 15 standard coal for Liaoning power grid every year80,000 tons, reducing carbon dioxide emissions by 3750,000 tons, sulfur dioxide 070,000 tons, which plays an important role in ensuring the safe and stable operation of the power grid and optimizing the power supply structure.
A number of new energy storage demonstration projects in China have been accelerated.
In addition to traditional pumped hydro storage, new energy storage methods such as electrothermal molten salt energy storage, solar thermal energy storage, and electrochemical energy storage are emerging. What exactly are these new energy storage projects?What are the advantages?Let's find out
The world's first electric molten salt energy storage steam injection test station was recently completed and put into operation in Liaohe Oilfield. The test station uses electricity to heat molten salt when the load of the power grid is low, converts the electrical energy into heat energy and stores it in the liquid molten salt, and then continuously exchanges heat between the high-temperature molten salt and water to generate steam to provide steam for the surrounding heavy oil thermal recovery wells. The station has an energy storage capacity of 15 megawatts and can produce 480,000 tons, replacing 3.13 million cubic meters of natural gas and reducing carbon dioxide emissions by 6,768 tons.
Sun Yan, President of PetroChina Liaohe Oilfield Design InstituteUncleThe basic principle of the project is to use molten salt with the characteristics of high melting point, high hot melt and high flexibility, which can be used as an energy storage medium and a heat transfer medium. During the preferential policy period of using grain time electricity at night, we store the green grain time electricity in electric molten salt.
In the world's first "twin towers and one machine" solar thermal energy storage project in Guazhou, Gansu Province, nearly 30,000 heliostats reflecting sunlight are used to store the heat energy of sunlight in the molten salt in the heat absorption tower, and finally drive the steam turbine to generate electricity. This power generation is not affected by changes in light intensity, and can produce electricity continuously and stably.
Zhang Long, General Manager of Three Gorges Energy:The project is equipped with two concentrating heat collection units, which can improve the optical efficiency by about 24% under the same conditions. At the same time, it is equipped with a 6-hour molten salt heat storage system, which has the characteristics of long energy storage time, fast response speed and stable power output.
In Inner Mongolia, the electrochemical energy storage power station with the world's largest single power has been successfully connected to the grid. These containers are equivalent to large batteries, which can store electrical energy efficiently, up to 600,000 kilowatt-hours of electricity, which is equivalent to the electricity consumption of 200 families in a year.
Gao Yongfeng, head of Huaneng Shangdu Wind Power Base:Our energy storage power station can quickly respond to peak discharge in milliseconds, and "peak shaving and valley filling" in the first time, greatly improving the utilization efficiency of new energy sources such as wind and solar.
China's new energy storage projects that have been completed and put into operation rank among the top in the world.
With the implementation of a series of energy storage-related policies and plans, the continuous progress of science and technology, and the continuous emergence of new energy storage technologies, which provide strong support and guarantee for the rapid development of new energy storage projects.
At present, China has established a complete energy storage industry chain, including batteries, inverters, energy storage systems and other links, which makes China more competitive in the field of energy storage. Compared with foreign countries, China has the advantages of low cost, complete industrial chain, policy support and strong innovation in the field of energy storage.
According to the latest data, as of the end of September this year, the cumulative installed capacity of new energy storage projects that have been completed and put into operation in China has reached 21.23 million kilowatts, ranking among the top in the world.
The reporter visited the Ulanqab "source-grid-load-storage" test base.
There are many "charging treasures" hanging on the power grid, and they are also different capacities and different types of "charging treasures". So how to safely and efficiently coordinate these "power banks" and cooperate with the power grid, so the "source-grid-load-storage" technology came into being. The so-called "source-grid-load-storage" refers to "power supply", "power grid", "load" and "energy storage". This smart technology uses energy storage systems to combine renewable energy with the power system to enable flexible storage and** of energy. "Source-grid-load-storage" is also an important support for accelerating the construction of a new power system with new energy as the main body.
How does the "source-network-load-storage" work?In the Three Gorges Ulanqab, there is a "source-grid-load-storage" technology research and development test base, where seven new energy storage technologies are being experimentally verified.
Reporter of the main station:In the energy storage laboratory of the Three Gorges Ulanqab "source-grid-load-storage" technology R&D test base, the big guy that looks like a container is the "energy storage cabinet", and each energy storage cabinet represents a new energy storage method. Since 2020, CTG, together with more than 20 top domestic scientific research institutions and universities such as the Chinese Academy of Sciences and Tsinghua University, has conducted experiments here to find effective solutions for the large-scale application of energy storage systems in different scenarios in the future.
At present, the base has 7 new energy storage methods, including lithium-ion energy storage, sodium-ion energy storage, flow battery energy storage, compressed air energy storage, flywheel energy storage and hydrogen energy storage.
He majored in the Comprehensive Energy Center of the Three Gorges Institute of Science and TechnologydivisionWu ZhuoHikoThis system is an all-vanadium flow battery energy storage system, and its energy is mainly stored in the electrolyte. During the work, the electrolyte passes through the pipeline and the pump and comes to the stack. When charging, the electrolyte of the cathode oxidizes from positive tetravalent to positive pentavalent, storing the electric energy, and when discharging, it returns from positive pentavalent back to positive quadrivalent, releasing the electric energy.
Researchers told reporters that the current energy storage methods are mainly divided into physical energy storage, electrochemical energy storage and electromagnetic energy storage. Among them, electrochemical energy storage is the most widely used energy storage method in the industry. It has the characteristics of high conversion efficiency, fast response speed and flexible configuration, which can greatly meet the needs of the power system for peak regulation and frequency regulation.
Han Junfei, Director of the Ulanqab Source Grid Load Storage Project Department of the Three Gorges Corporation Academy of Science and Technology:The advantages of electrochemical energy storage are obvious, but due to its own characteristics, there are also some limitations, such as its cycle life and economy, which need to be improved. At the same time, it also has some environmental protection problems, so in the future large-scale energy storage system application process, this is an urgent problem to be solved.
Compared with electrochemical energy storage, physical energy storage has good environmental friendliness. At the base, the multi-source thermal storage compressed air energy storage project under construction is entering a sprint period. This platform uses air compressors and turbines to store electrical energy.
Reporter of the main station:The heat storage and exchange device is a key link in the compressed air energy storage system. This is a trough CSP module, with a curved metal plate like a long concave mirror, and a black oil pipe in the middle is exactly at the focal point of the concave mirror. The sunlight is reflected, the heat energy is reflected to the oil pipe, the oil in the pipe is continuously heated for more than 200 meters, and it can reach 300, and the air is heated by the hot oil, so that the air expands, and the generator is driven to operate, so as to realize the conversion of air kinetic energy and electrical energy.
Han Junfei, Director of the Ulanqab Source Grid Load Storage Project Department of the Three Gorges Corporation Academy of Science and Technology:As a form of physical energy storage, compressed air energy storage is suitable for large-scale and has a long cycle life, but its one-time investment is relatively high, subject to some geographical conditions or some special application scenarios, and is not suitable for some users of small power energy storage.
Han Junfei told reporters that different energy storage methods have their own advantages and disadvantages, and then adapt to different scenarios. In the future, different energy storage methods, power sources, and load multi-energy complementarity and coordinated operation will become a new trend in the energy storage industry.
Visit China's first "zero-carbon" island to see the new model of "wind, solar, agriculture and storage" integration.
At present, the construction of new energy systems represented by "wind, solar and storage" has been significantly accelerated, and there are more and more green and intelligent wind power and photovoltaic development models. Dongyu Island, located in Boao, Hainan Province, has abundant sunlight all year round, and the local area has made full use of rich solar energy resources to build an integration of "wind, solar, agriculture and storage" integrating photovoltaic power generation, green buildings, breeze power generation, energy storage facilities, and efficient agricultural production, exploring a new path for wind power and photovoltaic to empower green islands.
CCTV reporterZhang CongjingOn Boao Dongyu Island, green power equipment can be found everywhere. Electric vehicle charging relies on the island's wind and light resources. The flower-like installation is the wind turbine on the island. Unlike common wind turbines, which have huge blades, they are so small that they can be turned by a slight wind and can generate wind energy without noise. The floor tiles on the island are also very special, which can be used to generate electricity from solar energy, and more than 100 square meters of photovoltaic floor tiles can generate electricity for 5 household air conditioners per day.
Not only within reach, the reporter saw that there are many photovoltaic modules hidden in the roofs, exterior walls, railings, and corridors of the buildings on the island, which can be used to generate electricity and provide clean energy. Dongyu Island maximized the use of building roofs, facades, landscape facilities, etc., laid photovoltaic power generation systems, and built 48 MW of distributed photovoltaics, all of which have been put into operation and connected to the grid for power generation.
At the same time, the island has also built a new intelligent charging station for photovoltaic storage and charging vehicles, which uses liquid cooling technology to fully charge the vehicle within 10 minutes at the earliest. The construction of smart parking lots and smart charging stations provides an important guarantee for green traffic and realizes the new application scenario of multi-network integration of "transportation and electricity" on the island.
Yan Liang, Director of Boao Photovoltaic Power Station of Hainan Company of National Energy Group:We fully integrate wind power and photovoltaic with the buildings and environment on the island, so that the building can change from energy consumption to production capacity, and photovoltaic equipment to landscape, and build a "zero-carbon" island of green power generation, green building and green transportation, and the project can provide 29.46 million kWh of clean electricity every year.
Not only on the island, the reporter saw that the farmland near the island has also achieved "zero carbon". A photovoltaic power generation project with a capacity of nearly 20 megawatts and an area of 330 acres has been built here, including photovoltaic power generation facilities and agricultural greenhouses. It can not only provide nearly 25 million kWh of green electricity for Dongyu Island every year, but also ensure the stability of the island's "vegetable basket".
It is understood that the total planned installed capacity of the entire project is 248 megawatts, saving about 8,912 tons of standard coal and reducing carbon dioxide emissions by about 23,350 tons.
Energy storage will further explore the commercial operation mechanism.
At present, most of the energy storage facilities are supporting the construction of new energy stations, and the investment, construction, operation and maintenance are usually borne by power generation enterprises, which brings greater economic costs to enterprises and restricts the sustainable development of energy storage power stations to a certain extent
In Rudong, Jiangsu, Jiangsu's largest shared energy storage power station has been officially connected to the grid. Although it is called a power station, it does not produce electricity, but is only a "porter" of electricity. At night, when the electricity consumption is low, charge the energy storage battery from the power grid, and wait until the peak of electricity consumption during the day, and then discharge to the grid.
The reporter noted that this energy storage project has two key attributes: "sharing" and "independent power station". It is understood that the power station is invested, built and operated by a third party, and participates in electricity market transactions in an independent capacity. "Sharing" means that the energy storage power station is not limited to serving a single power generation or power consumer, but opens the energy storage facilities to multiple users, and users can purchase the corresponding share of electricity according to their own needs and capabilities.
Three Gorges Electric Energy Jiangsu FengSavingsWei Yongqing, site leader of the shared energy storage project:As an independent entity, the power station directly signs a grid-connected dispatching agreement with the power dispatching agency, which is to provide supporting capacity for new energy power generation enterprises, provide peak regulation and frequency regulation services for the power grid, and provide users with high-quality spot trading varieties.
In July 2021, the concept of "shared energy storage" was unveiled for the first time. The National Development and Reform Commission and the National Energy Administration jointly issued the "Guiding Opinions on Accelerating the Development of New Energy Storage", pointing out that the status of new energy storage as an independent market entity should be clarified, energy storage should be encouraged to participate in the auxiliary service market as an independent market entity, and the construction of shared energy storage should be explored.
The "independent + shared" business model improves the utilization rate and operational value of energy storage power stations, broadens the revenue channels of power stations, and promotes the healthy and sustainable development of the energy storage industry.
Xu Dongjie, Deputy Chief Engineer of Electric Power Planning and Design Institute:Because new energy storage is an emerging thing, it is now building a unified national market, and we also propose that new energy storage should participate in this market as an independent market entity. Falling costs and technological progress will give rise to more business models in the future, which can further promote the overall development of energy storage.
CCTV reporter Zhang Wei, Zhang Congjing, Li Qingbo, **Wang Bofeng).
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