Jiangsu Jintan salt cave compressed air energy storage project location, which is the world’s first non-afterburning compressed air energy storage power station.
Photo courtesy of China Huaneng Group
The container energy storage system developed by Shandong Dongying Kunyu Power Technology Co., Ltd. integrates energy storage, battery management and other technologies, and has recently achieved the first batch of secondary exports. The picture shows the company’s workers testing the energy storage containers that will be delivered soon.
Photo by Zhou Guangxue (People’s Vision)
When electricity consumption is low, it is "charged" and stored through the power grid, and the stored electric energy is released until the peak of electricity consumption to ensure the stability of the power system — — This kind of energy storage power station, whose principle is similar to "charging treasure", has been widely used in China in recent years, which has played an important role in stabilizing power supply.
A few days ago, the National Development and Reform Commission and the National Energy Administration issued the Notice on Further Promoting the New Energy Storage to Participate in the Electricity Market and Dispatch (hereinafter referred to as the Notice), clarifying that the new energy storage can participate in the electricity market as an independent energy storage, and making arrangements for its market mechanism, price mechanism and operation mechanism. According to industry analysts, this move will strongly promote the development of new energy storage industry, and then provide strong support for China to build a new power system.
What is new energy storage?
— — Besides pumped storage, new energy storage technologies include new lithium ion batteries, flow batteries, compressed air, etc.
Have you ever seen a power station that doesn’t burn coal or natural gas, but lets the air "show its talents"?
On May 26th, Jiangsu Jintan Salt Cave Compressed Air Energy Storage Project was officially put into operation. Cao Qingwei, the chairman of Jiangsu Company of China Huaneng Group, who is responsible for the construction and operation of the project, told this reporter that as the world’s first non-afterburning compressed air energy storage power station, the power station does not burn coal or natural gas, but drives the turbine generator set to rotate and generate electricity through compressed air. When the electricity consumption is low, the air is compressed into the salt cave by electric energy, and the air is released at the peak of electricity consumption to generate electricity. After the project is put into production, it can provide 60,000 kilowatts of peak-shaving capacity for local power grids, and can store 300,000 kWh of electricity in one energy storage cycle, and increase the peak-shaving power by about 100 million kWh every year, thus realizing "peak-shaving and valley-filling" of power supply and demand.
Compressed air energy storage is a new energy storage technology, and its function can be commonly understood as "charging treasure". As the power is ready to use, it is often necessary to increase the power investment according to the peak load demand, which is not only costly, but also prone to surplus power supply. Using energy storage technology to store power at the low power consumption and release it at the peak power consumption can effectively avoid the "uneven busy and idle" of power system and ensure the stability of power supply.
"New energy storage is relative to traditional energy storage." Ceng Ming, director of the Energy Internet Research Center of North China Electric Power University, told this reporter that the main representative of traditional energy storage is pumped storage power stations, while new energy storage refers to new energy storage technologies other than pumped storage, including new lithium-ion batteries, flow batteries, compressed air and mechanical energy storage.
"In recent years, the traditional energy storage represented by pumped storage power stations has developed rapidly, and the technology is relatively mature and widely used." Ceng Ming said that promoting the development of new energy storage on this basis is closely related to its characteristics of quick response, wide functions, flexible configuration and short construction period. From the site selection and layout, the new energy storage has more space to be laid out and stronger environmental adaptability. It can be deployed on the power generation side, power grid side and user side, and can be laid out in a large scale or distributed manner. From the function point of view, the new energy storage can play the role of peak regulation and frequency modulation, and can also be used as a backup power supply to smooth the fluctuation of wind power generation and photovoltaic power generation.
In recent years, China has accelerated the development and utilization of renewable energy, and the concept of green and low carbon has been deeply rooted in people’s hearts. However, wind power and photovoltaic have the characteristics of "looking at the sky and eating". When it is "extremely hot without wind" and "extremely cold without light", it will easily lead to fluctuations in power supply. "To maintain the stability of frequency and voltage, it is necessary to systematically schedule energy storage resources to smooth the fluctuation of new energy power generation." Ceng Ming said that this includes unified dispatching of power system and optimized dispatching of distributed new energy storage within its own scope. In recent years, new formats such as virtual power plants can also ensure power stability by dispatching energy storage resources.
Clarify the identity of market subject
— — New energy storage can participate in the power market as an independent energy storage; If an independent energy storage power station sends electricity to the power grid, the corresponding charging amount will not bear the transmission and distribution price, government funds and surcharges.
With the accelerated development of renewable energy, the construction of new energy storage projects in China has obviously accelerated. By the end of 2021, the cumulative installed capacity of new energy storage in China has exceeded 4 million kilowatts, and application scenarios such as "new energy+energy storage", conventional thermal power configuration energy storage, and smart microgrid are constantly emerging, and the business model is gradually expanding, which initially shows its supporting role for energy transformation.
However, due to the lack of clarity in the identity positioning and investment return mechanism of new energy storage in the power market, the enthusiasm of market participants for investment and construction has been affected to some extent. "In the past, the relevant market rules mainly clarified that energy storage participated in the auxiliary service market of peak shaving and frequency modulation. However, the design of rules for energy storage participating in medium and long-term transactions, spot transactions and other markets, especially the access standards and registration, trading and settlement rules, still needs to be refined and improved." Huang Bibin, deputy director of the Institute of New Energy and Statistics of State Grid Energy Research Institute, told this reporter.
From the power generation side, at present, most of the new energy storage in China is combined with new energy or thermal power generating units, and the adjustment function of energy storage is used to improve the frequency modulation performance of thermal power, and the compensation for frequency modulation auxiliary services is obtained, and the related benefits are not high. In terms of independent energy storage, if the charging and discharging price mechanism is not clear, if it is implemented with reference to the traditional price mechanism of power users and generator sets, the power station, as a power user, needs to pay the on-grid price, transmission and distribution price, government funds and additional and related taxes and fees; However, when discharging to the power grid, independent energy storage is equivalent to a generator set, and only benefits such as electricity price and auxiliary services are obtained. When the power grid sells the electricity released by independent energy storage to the end users, the buyers still have to pay the transmission and distribution price, government funds and surcharges.
In order to better promote the development of new energy storage industry, the Notice issued this time proposes that new energy storage can participate in the power market as an independent energy storage. At the same time, accelerate the promotion of independent energy storage to participate in the power market and cooperate with the peak shaving of the power grid. If an independent energy storage power station sends electricity to the power grid, the corresponding charging amount will not bear the transmission and distribution price, government funds and surcharges.
"Encourage the signing of market contracts during peak hours and low hours, and refine the profit mode of independent energy storage participating in the power market; It is clear that the charging amount does not bear the transmission and distribution price, government funds and surcharges, etc., which solves the problem that the original charging amount price mechanism is unclear, and is conducive to promoting the development of independent energy storage and making profits in a market way. " Huang Bibin said.
Taking Shandong Province with independent energy storage power station as an example, according to the purchasing electricity price released by Shandong Electric Power Company of State Grid in March this year, the electricity transmission and distribution price for power users of 220kV and above is 0.1169 yuan/kWh, and the government funds and surcharges are about 0.027 yuan/kWh. According to industry insiders, after the implementation of the new policy, the independent energy storage participating in the spot market in Shandong will benefit directly, and the income from power consumption is expected to increase from 0.1 yuan to 0.2 yuan/kWh.
Promote the development of large-scale "charging treasure"
— — New energy storage on power generation side, user side and power grid side can participate in market transactions; Accelerate technical support and promote new energy storage to achieve high-quality development
On May 27th, the civil engineering of flywheel energy storage project of Ningxia Electric Power Lingwu Company, the national energy group, was completed, becoming the first full-capacity flywheel energy storage project in China — The project of combined frequency modulation of thermal power is also the project with the largest power of flywheel energy storage unit and the largest total energy storage in the world. "The biggest feature of this project is full magnetic levitation, low energy consumption and fast response. The life cycle can be designed as 25 years, and more than 10 million times of storage and discharge can be realized during this life cycle. The conversion between charging and discharge can reach millisecond level, which can effectively meet the needs of rapid frequency modulation of power grid." Diao Shijun, deputy general manager of Ningxia Electric Power Lingwu Company of National Energy Group, told the reporter.
At present, the new type of energy storage with configuration is mainly used to adjust the instability of power generation. The Notice proposes that new energy storage projects in the form of distribution and construction should be encouraged to be combined with other types of power supplies and regarded as a whole, and participate in the power market in accordance with existing relevant rules. At the same time, encourage new energy stations and energy storage facilities to jointly participate in the market, use energy storage to improve the network-related performance of new energy, and ensure the efficient consumption and utilization of new energy.
"Encouraging the joint participation of new energy distribution and its affiliated power sources in the power market will help the new energy storage to better carry out medium and long-term time-sharing curve trading, improve the performance of new energy in the spot market, and provide more support for power system regulation, which will further promote the development of new energy storage technologies on the new energy side." Huang Bibin said.
In addition to the power generation side, the Notice also puts forward requirements for the market-oriented construction of new energy storage on the user side and the power grid side, clearly further supporting the development of energy storage on the user side, "moderately increasing the peak-valley price difference to create space for the development of energy storage on the user side" and "encouraging further increasing the upper and lower prices of the medium and long-term power market and the spot market, guiding the user side to actively allocate new energy storage, and increasing the revenue channels for energy storage on the user side". At the same time, it is required to establish a price mechanism for energy storage on the grid side.
Huang Bibin told reporters that taking lithium-ion battery energy storage, which has developed rapidly in recent years, as an example, the current system construction cost is about 1,500 yuan ~ 2,000 yuan/kWh, but the life-cycle electricity cost is still 2-mdash of pumped storage; Three times. "The promulgation of the Notice will create conditions for new energy storage such as lithium-ion battery energy storage to participate in various power markets and obtain reasonable income."
The growth of the new energy storage industry is also inseparable from technological innovation. Huang Bibin believes that the new energy storage technology in China has made great progress at present, but the core indexes such as efficiency, capacity and service life still need to be broken, especially when the output time of new energy is limited under extreme weather conditions, there is a lack of new energy storage technology with large capacity and long period for system regulation. He suggested that in the future, with the goal of ensuring power supply and the safe and stable operation of the power grid, we should focus on promoting the research and development and system integration of new energy storage core technologies and equipment with large capacity, long period, low cost and high safety by deepening collaborative innovation of Industry-University-Research users and developing demonstration applications, so as to help the new energy storage industry achieve high-quality development.
