When the power consumption is low, use the electric energy to compress the air into the salt cavern;
When the power consumption peaks, the air is released to drive the air turbine to generate electricity.
In the salt cavern compressed air energy storage project in Jintan, Jiangsu, the thousand-meter underground salt cavern is transformed into a large-scale “power bank”. One energy storage cycle can store 300,000 kWh of electricity, which is equivalent to the electricity consumption of 60,000 residents a day.
This compressed air energy storage is part of a new family of energy storage. Recently, my country issued the “14th Five-Year” New Energy Storage Development Implementation Plan, which proposed that by 2025, new energy storage will enter the stage of large-scale development from the initial stage of commercialization, and meet the conditions for large-scale commercial application.
So, what exactly is new energy storage? How to develop during the “14th Five-Year Plan” period?
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.
Of course, traditional pumped storage is not a “yesterday’s old flower”. Pumped storage is still the most mature and economical energy storage technology at present. It has formed a clear business model and is suitable for large-scale development and construction.
You must know that wind power and photovoltaics are “eating from the sky”, and their power generation is volatile and intermittent, “extremely hot and windless” and “extremely cold and dull”. With the large-scale and high-proportion application in the future, coupled with the transformation of coal power and the slowdown of new installed capacity, if there is no wind, no light, cold and freezing extreme weather, the output of wind power and photovoltaic power generation will be greatly reduced, and who will supply the power To protect?
The role of energy storage can be commonly understood as a “power bank”, charging when wind power and photovoltaics are booming or when power consumption is low, and discharging when wind power output is small or power consumption is peaking. It can not only smooth 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.
The construction cycle of new energy storage is short, the site selection is simple and flexible, the adjustment ability is strong, and the matching with the development and consumption of new energy is better. The advantages are gradually highlighted. It is imperative to accelerate the large-scale application of advanced energy storage technology.
For example, the construction period: the construction period of the pumped storage power station is usually 6 to 8 years, the construction period of the electrochemical energy storage project in the new energy storage is 3 to 6 months, and the construction period of the new compressed air energy storage project is generally 1.5 to 2 years .
Another example is site selection and application scenarios: the site selection of pumped storage power stations often requires a place with a large terrain drop, but with strong capacity benefits and a large single-station scale, it is suitable for large-scale and system-level applications on the grid side; the new energy storage single-station body The volume can be large or small, with strong environmental adaptability, and 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 for pumped storage.
Looking at the adjustment ability, the response speed of the new electrochemical energy storage is fast, and it can respond in milliseconds to seconds.
At present, my country’s new energy storage has realized the transition from research and development demonstration to the initial stage of commercialization, and has achieved substantial progress. Lithium-ion batteries, compressed air energy storage and other technologies have reached the world’s leading level.
For example, electrochemical energy storage technology, in the past five years, the energy density of lithium batteries represented by CATL has more than doubled, the cycle life has increased by 2 to 3 times, and the application cost has dropped by more than 60%.
In the past, new energy storage was more used as an auxiliary part of thermal power plants to participate in frequency regulation. After the independent market position is clarified, combined with the introduction of electricity price policies in the future, new energy storage can independently participate in grid-connected dispatching, transaction settlement, etc., which is conducive to accelerating the development of new energy storage. The pace of marketization.
However, there is a phenomenon that needs to be paid attention to: more than 80% of the new energy storage projects currently under construction are lithium-ion batteries, accounting for the highest proportion. In 2021, among the new energy storage projects newly put into operation in China, the top ten energy storage technology providers with installed capacity are: Ningde Times, China National Energy Storage, EVE Power, Penghui Energy, Narada Power, Haiji Xin Energy, Lishen, Envision Power, China Innovation Aviation and Zhongtian Technology. In 2021, among the new energy storage projects newly put into operation in China, the top ten energy storage PCS providers with installed capacity are: Shangneng Electric, Kehua Shuneng, Soying Electric, NARI Jibao, Sunshine Power, Shenghong shares, Huazi Technology, Zhiguang Energy Storage, Inovance Technology and XJ.
Other types, such as flow batteries, lead-acid batteries, heat storage and cold storage, account for a relatively small proportion. The overall performance of lithium battery energy storage is good, but safety issues and resource recovery issues still need to be further resolved; liquid flow batteries are safe and easy to recycle and regenerate, but the system cost is relatively high.
Upstart energy storage: all-vanadium redox flow battery
Different from lithium resources, China is a big country of vanadium resources, its reserves rank first in the world, and the pricing power is also in our own hands, which is more proactive.
The all-vanadium flow battery is a kind of flow battery, which uses the change of the valence state of vanadium ions to realize the storage and release of electric energy. It operates under normal temperature and pressure. The electrolyte is an aqueous solution. The reaction process only involves the change of the valence state of vanadium ions. The electrolyte can be recycled. Compared with lithium-ion batteries, all-vanadium redox flow batteries are safer. The all-vanadium redox flow battery has a high number of cycles, reaching more than 15,000 times, and its lifespan can be as long as 20 years.
According to reports, State Grid, State Power Investment Corporation, National Energy Group, Huadian Group, Datang Group, Shanghai Electric, etc. have all been involved in all-vanadium redox flow battery projects. The all-vanadium redox flow battery system put into operation earlier in China is the former Guodian Longyuan Woniushi wind power energy storage project and the Dalian liquid flow battery energy storage peak-shaving power station national demonstration project. Both projects use the Chinese Academy of Sciences Dalian Chemical Physics Institute for flow battery technology. Shanghai Electric’s 2021 mid-term report shows that the 1MW/1MWh all-vanadium redox flow battery energy storage power station independently developed and manufactured by Shanghai Electric has successfully passed the acceptance inspection in the Wind Power Industrial Park in Haojiang District, Shantou City, Guangdong Province.
According to reports, the upstream, midstream and downstream leaders of the all-vanadium redox flow battery industry chain, represented by Vanadium Titanium Co., Ltd., a leader in vanadium products with a market value of over 47 billion yuan, and Dalian Rongke Energy Storage, are working together with Panzhihua, the capital of vanadium and titanium, to create a “China Vanadium Power Capital”.
In October 2022, Vanadium Titanium Co., Ltd. and Dalian Rongke signed a “Joint Venture Agreement” to jointly invest 31.61 million yuan to establish Sichuan Vanadium Energy Storage Technology Co., Ltd., of which Vanadium Titanium Co., Ltd. accounted for 51% of the registered capital, and Dalian Rongke accounted for the registered capital. 49%.
In any case, the new energy storage has become unstoppable.
At the same time, new energy storage is also an important support for achieving the goal of carbon neutrality at the peak of carbon dioxide, and it is also an important channel for participating in international competition.
At present, a green energy storage technology innovation system that takes enterprises as the main body, is market-oriented, and combines production, education, research and application is taking shape.
New energy storage, the future can be expected.