Diversified energy storage in Shaanxi Province

The interviewed insiders said that the choice of energy storage development route in Shaanxi Province is the choice of cost and market demand, which is closely related to the actual demand and technical bottleneck of the development of new energy and energy storage in Shaanxi Province.

Recently, Shaanxi Provincial Department of Science and Technology announced the construction list of "Shaanxi Provincial Engineering Technology Research Center" in 2022, and the "Shaanxi Provincial Wind Power Generation and Multiple Energy Storage Engineering Technology Research Center" was approved. Since the implementation opinions of carbon peak carbon neutrality in Shaanxi Province this year have accelerated the application of diversified energy storage technologies, various energy storage forms such as pumped storage, compressed air storage in salt caverns, and large-scale centralized shared energy storage at the power supply side are being explored in full swing.

The interviewed insiders said that the choice of energy storage development route in Shaanxi Province is the choice of cost and market demand, which is closely related to the actual demand and technical bottleneck of the development of new energy and energy storage in Shaanxi Province.

The problem of new energy consumption has become increasingly prominent

In recent years, the installed capacity of renewable energy in Shaanxi Province has been continuously improved, and has exceeded 30 million kW up to now, including 12 million kW of wind power and 14 million kW of photovoltaic power. It is expected that by the end of the 14th Five-Year Plan, the installed capacity of renewable energy in Shaanxi Province will reach 65 million kW, and the proportion of non-fossil energy consumption will reach more than 16%.

The load of scenic new energy in Shaanxi is mainly concentrated in Guanzhong and northern Shaanxi, the load in Guanzhong accounts for 56.2%, the load in northern Shaanxi accounts for 32.2%, and the load in southern Shaanxi accounts for 11.6%. This area is also a heavy load concentration area, the Guanzhong-Japan composite peak-valley difference is large, Yulin Yan 'an area of northern Shaanxi Province load growth rate is fast. This year, the cumulative power generation of new energy in Shaanxi Province is 1.1 billion KWH, and the peak-valley difference during the summer heavy load period is more than 10 million kW. The power grid has an urgent demand for new energy consumption and daily peak regulation.

According to Zhang Weijia, chairman of Shaanxi Electric Energy Storage Co., LTD., "The southern part of Shaanxi Province has abundant hydropower resources and conditions for the construction of pumping and storage power stations. However, due to the small power load in the region, the 750-kilovolt main grid has not been extended, the Internet transmission is limited, the scenic resources in the region are lacking, and there is no consumption demand, so it is not suitable for large-scale pumping and storage project construction. The 750-kilovolt main network in Guanzhong and northern Shaanxi has been completed, and it has four outbound channels, which are suitable for large-scale energy storage power stations. Based on this, we set up Yulin Electric Energy Storage Co., LTD. At present, we focus on developing diversified power grid energy storage projects in Guanzhong-Northern Shaanxi region, serving new energy Internet access and users' safe and reliable electricity consumption, and serving the sustainable and high-quality development of regional economy."

Guo Tingbo, deputy director of the new Energy Department of Shaanxi Provincial Energy Bureau, said that the new energy storage has become an indispensable supporting facility to ensure the safety, stability and economic operation of the power system due to its flexible site selection, short construction period, rapid and flexible response and diverse functions. During the 14th Five-Year Plan period, Shaanxi Province strives to achieve a cumulative installed capacity of new energy storage of more than 2 million kW, breed a group of market players with core technologies, form a relatively perfect technology and standard system, and initially form a business model of new energy storage in the source network load side.

Building energy storage projects according to local conditions

Guo Tingbo introduced that in terms of route selection of energy storage technology, Shaanxi Province takes promoting the development and demonstration of diversified technologies as the starting point, and encourages and supports construction enterprises to carry out demonstration and application of heat storage, hydrogen storage, compressed air and other innovative energy storage technologies. "We have put forward the threshold requirements of energy storage system performance indicators and operation life cycle for mainstream lithium battery energy storage power stations to ensure the technological advancement and safety of the demonstration project."

"Energy storage technology choices also need to be tailored to local conditions. Together with the design and technical units of Power China, China National Energy Construction, China National Energy Storage and other subordinate companies, we conducted a survey of the regional resources in Shaanxi, worked out a preliminary plan and determined the pilot project." "For example, there are abundant salt cavern resources in Yulin, but they are generally below 2,600 meters deep, while the depth of the grid connected salt cavern compressed air energy storage demonstration project in China is around 800 meters. After field investigation and demonstration by the expert group, it is believed that the cost and efficiency of salt cavern compressed air energy storage are difficult to guarantee due to the technical bottleneck, and further technological breakthrough is needed. After field investigation, we chose to apply the salt cavern compressed air energy storage technology of Chinese Academy of Sciences to play its advantages of safe and stable production, high operation efficiency, short construction cycle, reasonable cost and long service life."

Zhang also said that the company has built 700 megawatt and 3,500 megawatt hour pilot energy storage projects based on Rocky Mountains in Sanyuan, Jingyang and Fengxiang in northern Guanzhong and around Yan 'an. At present, the preparation of the above project proposal has been completed and the preliminary work will be started in the near future. In order to reduce the risk, a 100MW unit will be built in the first phase, and the following two 300MW units will be started after the unit is put into operation. The project is expected to be fully completed and connected to the grid before 2025, which will effectively alleviate the limited consumption of new energy in the 750-kilovolt Xiazhou power supply area.

Industry insiders believe that in terms of operation mode, energy storage projects laid out on the grid side of Shaanxi Province will adopt two-part electricity price system or independent sharing of energy storage into market transactions, which depends on the subsequent relevant policies of Shaanxi Province. According to the relevant policies of other provinces, the independent shared energy storage trading mode is adopted, which is relatively economical and the total investment return rate can reach about 9%.

Explore and try the integration of "power transformation + energy storage"

"We are studying the scalable technology of the integrated station of 'power transformation and energy storage'." Zhang Weijia said that if each substation around the city can be equipped with a certain capacity and duration of energy storage facilities, it will greatly improve the peak regulation capacity and fault emergency capacity of the power grid, and also meet the national energy security and strategic needs. Some units tried to install the electrochemical energy storage module in the substation before, but all of them could not be solved due to fire safety problems, and finally shut down or dismantled. However, the power grid is in urgent need of this aspect. If the problems of efficiency, cost and footprint can be solved, physical energy storage will be widely used.

According to Zhang Weijia, 330 kV substation is located in the concentrated area of energy and chemical enterprises and new energy power, so it is of pioneering significance to explore the integration of "power transformation and energy storage". "Taking Shenmu Dabaodang Town in Yulin, Shaanxi Province as an example, its new energy access has been limited for a long time. We tried Shenmu Dabaodang 200MW / 1000MW hour integrated energy storage and transformation station. We have drawn up two schemes. The first is the technology of the Chinese Academy of Sciences. Using the existing large mine outside the station, the multi-layer or vertical gas storage tank is used to compress the air to build two 100MW units. The second scheme is to adopt the large atmospheric pressure flexible carbon dioxide storage chamber and compress carbon dioxide disguised phase energy storage in the Xi 'an Jiaotong University technology of Deyang East Gas pilot project. After the program is completed, the organization of expert review can achieve the cost efficiency, the later area is reduced to about 50 mu, it will be completely possible to deploy in Xi 'an and other large and medium-sized cities."

Source: China Energy News Author: Su Nan