-News Center-

In recent years, with the construction of larger-scale new energy sources, the contradiction between the long-distance separation of resource-rich areas and resource-consuming areas has become more and more prominent. Large-scale consumption has always been the focus of how to better consume new energy on the basis of ensuring the safety of the power grid. In addition to strengthening the construction of power grid and energy storage, the integration of source network and storage and multi-energy complementary technology have become the focus of the industry.

In March 2021, the National Development and Reform Commission and the National Energy Administration officially issued the "Guiding Opinions on Promoting the Integration of Power Source, Network, Load and Storage and Multi-energy Complementary Development", which clearly put forward the "Multi-energy Complementary Implementation Path" and "Promote the source network The guiding ideology of integration of load and storage, improving security capabilities and utilization efficiency", "promoting multi-energy complementarity, and improving the level of renewable energy consumption, it points out the significance of the development of" integration of source, network, load and storage "and" multi-energy complementary "in promoting China's energy transformation and economic and social development.

Under the trend of rapid development of new energy projects based on wind and photoelectric, in order to ensure the safe, stable and efficient operation of the power system, and to ensure that large-scale new energy can be smoothly and fully eliminated, the "source network, load and storage integration" model came into being.

　　Integration of source network, load and storage

The power system is an energy system that needs to be maintained in a state of balance between supply and demand in real time. In the traditional power system, the active and reactive power of each on-grid generator set is adjusted according to the change of demand side load, so as to maintain the safe and stable operation of the whole power system ".

The essence of "integration of source, network, load and storage" is to build a new type of power system, decompose a large power grid into multiple levels, and form a regional (provincial) level, city (county) level, and park (Residential area) level and other multi-level power grids coexist. Focus on the load demand as the center, through the power supply side, grid side, load side, energy storage side of the various power resource elements in the local, nearby, flexible adjustment, to achieve source-source complementary, source-network coordination, network-load interaction, network storage and connection, source-load matching of the power interaction form, give full play to the load side of the regulation capacity.

The basic working mechanism of source network load storage has the following three aspects: first, the characteristics of source, network, load and storage are analyzed to find out the current state and ability of each link of source network load storage. Secondly, the generation power, load power, etc. are predicted. Third, the development of the source network load storage coordination and optimization strategy, give full play to the energy storage "leak to fill the gap, cut the peak to fill the valley" role.

Problems faced

"Integration of source, network, load and storage" is the requirement of establishing a new power system. This mode will change all kinds of energy, especially many new energy sources, from "single work" to "group", and establish a solid and reliable systematic mechanism to ensure the balance of power supply and demand. However, at this stage, there are still a series of problems in the development of source network and load storage, especially the integration of large-base source network and load storage.

High cost of project construction

At this stage, the energy storage of the large-base source network-load storage integration project is mainly based on electrochemical energy storage equipment with a 10-20% installed ratio and a duration of not less than 1 hour at the source end. Most new energy storage technologies such as compressed air, flywheel energy storage and high-temperature molten salt heat storage are still in the demonstration application or promotion stage. In the context of this year's lithium iron phosphate battery price rise, energy storage system power market price mechanism has not yet formed, the early investment evaluation process of energy storage system business model is still unclear, the full life cycle rate of return is difficult to measure.

In particular, the "integration of source network, load and storage" project, which is mainly based on new energy supporting energy storage, is also facing the investment pressure of rising cost of photovoltaic modules. Taking the 10% proportion of wind photoelectric project allocation and the 1-hour electrochemical energy storage as an example, the calculation of the energy storage system cost of 1.8 yuan/Wh will directly increase the unit investment of the wind photovoltaic project by nearly 5%. And from the current point of view, in addition to the abandoned wind abandoned light area, the energy storage ratio as a new energy index competition area, electrochemical energy storage equipment investment can not bring direct benefits to the project.

The market price mechanism has not yet formed

At present, the implementation of demonstration projects are mainly small park (residential area) level, how to break through the four links of horizontal barriers, how to evenly distribute the income still needs to be explored, China's fair and effective price pricing and settlement mechanism is still in the process of continuous promotion of construction.

First, under the condition that the cost is significantly higher than that of other power sources, the transmission and distribution price of "the same network and the same price" is not fair to the large-base source network, load and storage integration project with nearby consumption and short transmission and distribution distance, which affects its economy from the aspect of transmission and distribution price.

Second, in terms of energy storage, in addition to load-side energy storage using peak-valley electricity spread arbitrage and pumped storage revenue, grid-side energy storage, power-side energy storage and load-side auxiliary FM services such as no effective pricing methods and business models, participation in the grid demand response settlement mechanism has not yet been unified.

Third, because the "virtual power plant" involved in the grid demand response does not have a clear geographical boundary and grid demarcation point, in the absence of a market mechanism for "virtual power plant", it is more difficult to promote load-side interactive regulation through demand-side management of "virtual power plant.

Traditional energy is deeply affected

The output of wind and solar power has certain seasonality and volatility, and the matching degree with the terminal load characteristics is not high, and the proportion of new energy is rapidly increasing, which brings new challenges to the power grid's power balance scheduling ability, and must rely on other conventional power sources to adjust. However, due to the high prices of coal and natural gas, coal-fired and gas-fired enterprises have already lost money, and they have to give way to new energy, and the reaction is relatively strong.

The attitude of the power grid to the source network load storage is not positive enough.

"Source network storage" in the key link "network" is still firmly in the hands of power grid enterprises, the current multi-grid enterprises for other investors unified development of "source network storage" cautious attitude, especially incremental distribution network business market has not been fully liberalized.

The relevant technical rules and standards are still not perfect

The "group" model of the large-base source, network, and storage integration project has further improved the integration requirements of the energy subdivision industry, and put forward higher requirements for project planning, approval, development, construction, and operation. In the face of the huge development space of the large-base source-network-load-storage integration project, a lot of research and practice have been carried out at home and abroad in the aspects of integrated energy system, multi-energy complementarity, and flexible transformation of thermal power units, and a series of research results and practices have been formed. Experience, but there are no corresponding implementation rules in the systematic planning, design and scheduling mechanism.

In addition, there is still a lack of technical standards for the implementation of the large-base source-network-load-storage integration project, and it is urgent to establish and improve the planning, construction, scheduling and operation mechanism to achieve the reliable operation of the "source-network-load-storage integration", and then gradually promote the application.

　Development recommendations

The installed capacity of large-base new energy projects is relatively large, and the existing projects are generally developed and constructed in the mode of integration of source, network, load and storage, multi-energy complementary projects, and some also combine new energy hydrogen production and new energy heating. In order to carry out the development and operation of the large-base source network-load storage integration project more smoothly, we believe that the following aspects should be strengthened to promote the implementation of the project:

Planning to lead, strengthen coordination, improve the construction of institutional mechanisms

It is suggested that the relevant departments of the state should organize the planning and construction of a new energy system as soon as possible, put forward guidelines and implementation opinions, formulate and improve the corresponding national and local energy development plans, optimize and industrial layout from the overall consideration, strengthen the power transmission planning and construction of resource areas and power receiving ends, and optimize the planning and integration of various projects in the region.

Second, it is necessary to adjust measures to local conditions, comprehensively consider the multi-scenario and typical configuration and operation mode of "integration of source, network, load and storage", strive to realize wind-solar complementarity at the source end of each project, plan and design the transmission capacity on the grid side more reasonably according to the change trend on the load side, plan and design the installed ratio of power supply and energy storage more reasonably, and develop the "dumbbell" mode in energy storage, I .e, in order to adjust the power generation output, the corresponding supporting energy storage should also be built at the load end to better adapt to the demand side load changes and further increase the reliability of power supply.

Third, we should further improve the energy storage scheduling mechanism, improve the relevant rules for energy storage to participate in grid-connected operation and auxiliary services, and maximize the role of energy storage system.

Fourth, it is necessary to establish a strong coordination mechanism between the upper and lower levels, clarify the coordination responsibility system of all relevant departments and levels, and seek truth from facts to standardize the unreasonable demands of local governments for hundreds of millions of industrial supporting facilities when transferring resources. and strengthen the supervision and coordination of the construction process of the integration project of power source network, load storage, and timely urge the relevant departments to solve the problems found.

First try, hierarchical implementation, to ensure the effectiveness of demonstration projects

Seize the development opportunity period in the first few years and intensify the development and construction of demonstration projects. It is best to follow the "small to large" layered implementation. The park (residential area)-level source network-load-storage integration project takes the development and construction of distributed power supply and the nearby access consumption as the starting point. It is the easiest type of project to implement and the test field for the comprehensive optimization of the entire "source network-load-storage" system.

Research can be carried out on the problems exposed in the planning, examination and approval, design, construction, management, operation and maintenance, settlement and other aspects of the park (residential area)-level source network-load-storage integration project, and norms, standards and schemes can be established accordingly, so as to accumulate experience for the planning, construction and implementation of the subsequent upper-level large-base source network-load-storage integration project at the city (county) and regional (provincial) levels.

Intensify efforts, focus on tackling key problems, and solve the technical dilemma of the system.

"Power system simulation analysis and safe and efficient operation technology", "flexible planning and operation technology of AC/DC hybrid distribution network", "integration and optimal operation technology of large-scale energy storage system", "integration and optimal operation technology of source, network, load and storage integration and multi-energy complementary integration design and operation technology" and "intelligent dispatching operation control and intelligent operation and maintenance technology of power grid" are included in "14th Five-Year Plan" modern energy system planning and "" Multi-user-friendly intelligent supply and demand interaction technology "," intelligent system integration and integrated energy service technology "as the current need to solve the key technical tasks, science and industry enterprises should also seize this opportunity, take the initiative to carry out relevant research, strive for breakthroughs in the field of" network "technology and coordinated control technology, actively participate in the formulation of relevant technical standards, and be able to take the lead in the technical level of the integration of source network, load and storage.

Encourage innovation, let a hundred flowers blossom, and promote equipment technology innovation

Adhere to science and technology is the first productive force, innovation is the first driving force, in-depth implementation of innovation-driven development strategy. In addition to systematic technological breakthroughs, advanced equipment technology breakthroughs are also one of the necessary conditions to promote the rapid development of large-base source network-load storage integration, especially the development of new energy storage technologies.

At present, most wind and solar storage projects use lithium iron phosphate batteries for energy storage, but their safety is still the focus of technological breakthroughs. Flow batteries have also achieved breakthrough development, with good safety, but energy density and cost still need to be improved. The 100-megabyte compressed air energy storage system has begun demonstration application, and the system efficiency will be further improved from 70%. Hydrogen production and hydrogen storage are also making positive progress.

At the same time, it can also strengthen the development of technical equipment such as terminal energy efficiency improvement and comprehensive energy utilization, promote the construction of scientific and technological demonstration projects, comprehensively improve the technical level of domestic electrical and electrical equipment, and achieve energy diversification, power grid intelligence, load averaging, and energy storage through intelligent regulation. The purpose of safety.

This article was first published in the 12th issue of Energy magazine in 2022. Authors: Shen Xiaogang, Chen Hongguan, Jiang Guotao, Li Jian, Yang Xiufang, Wang Haijun, Wu Yuejie)