New energy storage, how to build a large "charging treasure"? (New economic orientation)
When the electricity consumption is low, the electric energy is used to compress the air into the salt cavern; when the electricity consumption peaks, the air is released to push the air turbine to generate electricity.
In the Jiangsu Jintan Salt Cave Compressed Air Energy Storage Project, the salt cavern 1000 meters underground is transformed into a large "charging treasure", which can store 300,000 kWh of electricity in one energy storage cycle, which is equivalent to the daily electricity consumption of 60,000 residents.
This compressed air energy storage is part of a new "family" of energy storage.
A few days ago, the "14th Five-Year Plan" New Energy Storage Development Implementation Plan (hereinafter referred to as the "Implementation Plan") issued by the National Development and Reform Commission and the National Energy Administration proposed that by 2025, new energy storage will enter large-scale from the initial stage of commercialization. In the development stage, it has the conditions for large-scale commercial application.
What exactly is the new energy storage?
How will it develop during the "14th Five-Year Plan" period?
The reporter conducted an interview.
It can not only smooth unstable wind power photovoltaic, but also cooperate with conventional thermal power to participate in power system peak regulation and frequency regulation
Generally speaking, new energy storage refers to new energy storage technologies other than pumped storage, including new lithium-ion batteries, flow batteries, flywheels, compressed air, hydrogen (ammonia) energy storage, thermal (cold) energy storage, etc.
Why should high-quality, large-scale development of new energy storage?
This is an inevitable demand for improving the power system regulation capacity and ensuring the safe operation of the power system under the background of the rapid increase in the scale of new energy development and the continuous widening of the load peak-to-valley difference.
You must know that wind power and photovoltaics are all "seeing the sky to eat", and their power generation is fluctuating and intermittent, "extremely hot without wind" and "extremely cold without light".
With the large-scale and high-proportion application in the future, coupled with the transformation of coal power and the slowdown in the scale of newly installed capacity, if there is extreme weather with no wind, no light, cold and freezing, the output of wind power and photovoltaic power generation will be greatly reduced. Who will supply the power? to protect?
The role of energy storage can be commonly understood as a "charging treasure", which is charged when wind power and photovoltaics are in full swing or when electricity consumption is low, and discharged when the output of wind power is small or when electricity consumption is peak.
It can not only smooth the unstable photovoltaic power generation and wind power, increase the proportion of renewable energy, but also cooperate with conventional thermal power, nuclear power and other power sources to provide auxiliary services such as peak regulation and frequency regulation for the operation of the power system, and improve the flexibility of the power system.
On March 20, in the 35 kV Hongxing Substation in Shaoxing, Zhejiang, the last four container battery packs were hoisted to the predetermined position.
So far, Zhejiang's first 35kV grid-side direct-mounted energy storage power station has entered the countdown to grid-connected operation.
"The maximum power of the energy storage power station is 6 megawatts, which can support about 3,000 households with two air conditioners working for 2 hours at the same time." Chen Yuefeng, deputy chief engineer of the State Grid Shaoxing Shangyu District Power Supply Company, introduced that according to calculations, after the completion of the energy storage power station , the peak-to-valley difference rate of Shangyu 220 kV Daoxu Substation will drop from the current 43.5% to 35.4%, which will help to cut peaks and fill valleys and smooth the load curve.
The construction period is short, the site selection is simple and flexible, and the adjustment ability is strong
"The construction period of the new energy storage is short, the site selection is simple and flexible, the adjustment ability is strong, and it has a good match with the development and consumption of new energy. The advantages are gradually becoming prominent. It is imperative to accelerate the large-scale application of advanced energy storage technology." National Energy Introduction by the person in charge of the bureau.
Looking at the construction period, the construction period of pumped storage power stations is usually 6 to 8 years, the construction period of electrochemical energy storage projects in new energy storage is 3 to 6 months, and the construction period of new compressed air energy storage projects is generally 1.5 to 2 years. .
Looking at the site selection and application scenarios, "The site selection of pumped storage power stations often requires finding a place with a large terrain drop, but with strong capacity benefits and large single-station scale, it is suitable for large-scale and system-level applications on the grid side; new energy storage single-station systems It can be large or small, has strong environmental adaptability, can be flexibly deployed in various application scenarios such as power supply, power grid and user side, and can be used as an incremental supplement to pumped storage.” Deputy, Institute of New Energy and Statistics, State Grid Energy Research Institute Director Huang Bibin introduced.
Looking at the adjustment ability, the new electrochemical energy storage has a fast response speed, which can achieve a response of milliseconds to seconds.
According to the relevant person in charge of the National Energy Administration, since the "13th Five-Year Plan", my country's new energy storage has realized the transition from R&D demonstration to the initial stage of commercialization, and has achieved substantial progress.
Technologies such as lithium-ion batteries and compressed air energy storage have reached the world's leading level. By the end of 2021, the cumulative installed capacity of new energy storage will exceed 4 million kilowatts.
Taking electrochemical energy storage technology as an example, in recent years, key technical indicators such as battery safety, cycle life and energy density have been greatly improved, and application costs have dropped rapidly.
"In the past five years, the energy density of lithium batteries has more than doubled, the cycle life has increased by 2 to 3 times, and the application cost has dropped by more than 60%." Huang Bibin gave an example.
In the future, the development space of new energy storage is broad.
Chen Yongchong, head of the energy storage technology research group of the Institute of Electrical Engineering of the Chinese Academy of Sciences, said that although my country's installed energy storage capacity ranks first in the world, the ratio of energy storage to wind power photovoltaic new energy installed capacity (referred to as "storage-to-new ratio") is less than 7%; Relatively speaking, the average reserve-to-new ratio of other countries and regions has reached 15.8%.
With the rapid increase in the scale of new energy power generation, there is still a lot of room for growth in my country's new energy storage ratio.
Encourage different technical routes, "high security, low cost, sustainable" is the common goal
The "Implementation Plan" puts forward the basic principle of "market-led and orderly development", clarifies the independent market position of new energy storage, and proposes to give full play to the decisive role of the market in resource allocation.
"In the past, the new energy storage was mostly used as an assistant for thermal power plants to participate in frequency regulation. After the independent market status is clarified, in the future, combined with the introduction of the electricity price policy, the new energy storage can independently participate in grid-connected scheduling, transaction settlement, etc., which is conducive to speeding up the new energy storage. The pace of marketization." Chen Yongchong said.
New energy storage has many advantages and welcomes development opportunities, but from the perspective of the industry, in the future, there are at least two hurdles in safety and cost that need to be overcome in the development of scale, industrialization and marketization.
Safety is the bottom line for the development of new energy storage.
"At present, the lithium battery energy storage system has not yet achieved the goal of intrinsic safety. If the control is improper, there is a risk of combustion and explosion." Chen Yongchong believes that intrinsic safety technology needs to be developed in the future, that is, the internal safety and controllability must be achieved before the thermal runaway of the battery, which cannot be relied on. External fire-fighting measures after thermal runaway.
Huang Bibin believes that the safety standards and safety risk assessment processes for new energy storage modules and battery cabinets still need to be improved and standardized.
In this regard, the "Implementation Plan" proposes to strengthen the security risk prevention of new energy storage, clarify the main body of safety responsibility in each link of the new energy storage industry chain, establish and improve new energy storage technical standards, management, monitoring, and evaluation systems to ensure the construction of new energy storage projects. The whole process of operation is safe.
In terms of cost, taking the current mainstream electrochemical energy storage as an example, Huang Bibin introduced that according to the current general cost calculation, even if there are two charges and two discharges per day, the cost of a single charge and discharge in the whole life cycle exceeds 0.5 yuan/kWh.
Not only that, but increasing security investment will also increase the cost of energy storage projects.
He suggested to accelerate the promotion of advanced electrochemical energy storage materials with long life, low cost, high safety and high efficiency, as well as the research and development of new energy storage technologies with large capacity and long time, for the needs of power system application scenarios.
At the same time, it is necessary to speed up the establishment of cost alleviation mechanisms such as new energy storage prices.
"Currently, relevant departments have issued guidelines to accelerate the development of new energy storage, implementation plans for the 14th Five-Year Plan, etc., to encourage energy storage projects to divert costs and obtain benefits through the electricity market. However, the current market access conditions and trading mechanisms, etc. The detailed rules have not yet been clarified, the energy storage on each side lacks a mature business model, and the enthusiasm of enterprises to install energy storage is not high.” Huang Bibin suggested that the market mechanism for independent energy storage on the grid side should be further refined, and the price coordination mechanism for alternative energy storage on the grid side should be improved. , improve the peak-valley electricity price and peak electricity price policy, optimize the peak-valley electricity price difference, and create space for the development of energy storage on the user side.
In addition to safety and cost issues, Chen Yongchong believes that the current development of new energy storage still faces some problems. For example, some places require new energy to support energy storage, but the proportion of new energy storage is unscientific; Further clarify the grid-connected access and dispatching standards of new energy storage systems.
The technical route of new energy storage is diversified. According to the relevant person in charge of the National Energy Administration, the "Implementation Plan" strengthens the strategic layout and systematic planning for the innovation of new energy storage technology, proposes the direction of R&D and reserve technology, and encourages different technical routes to "bloom together". At the same time, taking into account the optimal allocation of innovation resources, "In addition, we must adhere to the principle of demonstration first, actively carry out pilot demonstrations in technological innovation, improve market systems and policy mechanisms, and drive technological progress and industrial upgrading through demonstration applications."
"More than 80% of the new energy storage projects currently under construction are lithium-ion batteries, accounting for the highest proportion; other types, such as flow batteries, lead-acid batteries, heat storage and cold storage, account for a smaller proportion. The overall performance of lithium battery energy storage is better, but Safety issues and resource recovery issues still need to be further resolved; flow batteries are safe and easy to recycle, but the system cost is high." Chen Yongchong believes that energy storage application scenarios are very rich, and the performance requirements of each scenario are different. The power requirements are high, and some have large capacity requirements. Energy storage technologies have their own characteristics. In the future, various energy storage routes will develop in parallel.
"Nevertheless, 'high safety, low cost, and sustainability' are the common goals of the development of all energy storage technologies. It is necessary to speed up the establishment of a green energy storage technology innovation system with enterprises as the main body, market-oriented, and the combination of production, education, research and use." Chen Yongchong said.
Our reporter Ding Yiting