What are the advantages of energy storage black start compared with other black start methods? At a time when the construction of power grids is becoming more intelligent and the probability of large-scale power outages is small, how should we view the market prospect of energy storage black start?
▲The picture shows the transformer and booster equipment of Dalian constant current energy storage power station NARI relay insurance/courtesy of the picture
The news of the successful start of energy storage has recently attracted widespread attention in the industry.
On June 17, Hubei Jingmen Xingang Energy Storage Power Station successfully implemented the first 100 MWh grid-based energy storage power station black start test in China; On June 18, State Grid Liaoning Electric Power organized Dalian Hengliu Energy Storage Power Station and Huaneng Dalian Power Plant to carry out a new energy storage black-start urban power grid large-capacity thermal power unit test, and successfully drove the thermal power unit of Huaneng Dalian Power Plant nearly 9,000 kilowatts of plant load, and the unit was ignited and connected to the grid.
Black start is one of the most difficult technical means in the power industry, and it plays an important role and value for the rapid disaster recovery of the power system. The success of the energy storage black start test verifies the feasibility of energy storage as a black start power point, and adds a hole card for power grid security. So, compared with other black start methods, what are the advantages of energy storage black start? At a time when the construction of power grids is becoming more intelligent and the probability of large-scale power outages is small, how should we view the market prospect of energy storage black start?
Resources are widely distributed
The so-called black start refers to the entire power grid system due to fault outage, the system is all out of power (not excluding the isolated small power grid is still running), in a full "black" state, not relying on other network help, through the system with self-starting ability of the generator set start, drive the non-self-starting ability of the generator set, gradually expand the scope of system recovery, and finally realize the recovery of the entire system, is vividly called the "last match" to light up the city.
"The above two black-start pilot projects both use NARI Jibao's energy storage equipment." Miao Nanlin, director of the energy storage industry of NARI Jibao, told the reporter of China Energy News that Dalian Hengliu Energy Storage Power Station and Huaneng Dalian Power Plant carried out the test of large-capacity thermal power units of the new energy storage black-start urban power grid, which is of different significance from the past. "It is to start energy storage as a large-capacity unit, electrify the urban backbone power grid, and then drive the large-capacity synchronous unit in the network to start, which is a complete black-start process of large-capacity power grid, and is the world's first new energy storage black-start urban power grid test."
Traditional black-start power supplies generally use gas turbines and hydropower units with self-starting capabilities. "With the development of coal-fired power plants to single-unit high-power and multi-unit, the distribution of black-start resources will tend to be uneven. Energy storage is the most widely distributed power generation equipment with black start capability, and can become a widely distributed black start resource. Miao Nanlin pointed out that with the increasing proportion of new energy, regional differences are becoming more and more significant, when new energy and energy storage become the main body of the new power system, the requirements for the rapid start of traditional energy will be higher and higher, and energy storage needs to give full play to the ability to start traditional power plants.
Zheng Hua, a professor at North China Electric Power University, told the China Energy News that although black start is a very low-frequency application scenario in the entire power system application scenario, with the frequent occurrence of special events such as extreme weather, black start is of great significance and value for quickly restoring the power grid supply capacity and ensuring power supply.
High technical difficulty
It is not easy for new energy storage to drive the recovery of the power system.
Theoretically, power generation projects can achieve black-start services. But in reality, the number of power generation projects with black start services in the country is relatively small. Zheng Hua explained that on the one hand, the location of the black start power supply is related to factors such as power grid and load distribution, and not every power supply can be used as a black start power supply; On the other hand, the black start power supply also needs to go through a variety of rigorous tests and experiments to finally determine the actual effect of black start. "Once a large-scale emergency occurs in the power system, a series of lines, transformers, loads and other primary and secondary equipment will be re-operated in strict accordance with the plan to ensure that the black start power supply can restore part of the load, gradually drive more power restoration, and gradually realize the restoration of power supply to the entire power system. At this time, if there is a problem with the power supply itself that bears the black start, it is likely to cause the recovery process to be prolonged and cause new losses. ”
According to the reporter of "China Energy News", the test of large-capacity thermal power units in the black start network of pure power electronic equipment is the first time in the world, and there is no experience to learn from, and it is difficult to predict the test risk of traditional theory and simulation analysis methods. In Miao Nanlin's view, the difficulty of black start of energy storage lies in the coordinated control of multiple PCS (converters), as well as the impact on energy storage when under load, which requires relevant enterprises to have in-depth research on the process and mechanism of black start of the power grid.
Traditional black start and energy storage black start have their own advantages and disadvantages. For example, the structure of the hydro generator is simple, there is no complex auxiliary system, the plant load is small, and the start-up speed is fast. However, due to the limitation of hydropower resources, the black start of hydropower units does not have flexible configuration conditions and cannot meet the black start requirements of all regions. The new energy storage has the advantages of flexible site selection, fast response speed and high control accuracy.
Zheng Hua further pointed out that the black start power supply is a power supply that does not require external power supply, and can rely on itself to realize the start and power generation of the unit. Only when the new energy storage itself has enough energy and power can it provide the required energy and power for a unit to start and achieve black start. "In other words, if the new energy storage provides black start services when the grid is abnormal, it needs to be able to provide the capacity required for the start-up of conventional units at any time, but in terms of long-term energy retention, the new energy storage does not have the advantage."
The outlook remains to be seen
On the whole, the mainland black start market is still in its infancy, and many places have successively introduced incentive policies on black start services in recent years to encourage various power sources and new energy storage to provide emergency recovery auxiliary services.
In 2022, the Yunnan Energy Regulatory Office issued the "Yunnan Black Start Ancillary Service Market Trading Rules (Trial)", which clearly states that in accordance with the principle of "who provides, who profits; Who benefits, who bears" principle, 50% of the compensation cost of black start auxiliary services will be channeled to the user side. In July 2023, the "Implementation Rules for the Management of Grid-connected Electric Power in Shandong Province" and the "Implementation Rules for the Management of Electric Power Ancillary Services in Shandong Province" issued by the Shandong Energy Regulatory Office clearly stated that the black start power supply will be compensated according to 300,000 yuan/time; Provide actual black start service due to power grid failure, and compensate according to 10 million yuan/time.
"Black start is included in the type of auxiliary services of the power grid, which was originally mainly undertaken by thermal power, hydropower, and gas units, and now can be provided by energy storage Black start services, which can increase the revenue of energy storage to a certain extent." Miao Nanlin said.
Zheng Hua believes that the frequency and number of large-scale power grid decoupling accidents are extremely low, and the existing new energy storage has a certain self-discharge rate, and if the long-term and large-capacity black start capacity is retained, it will produce higher costs. "Therefore, it is difficult for black start to form an effective market, even in the foreign power market mechanism with mature power market, the black start market often adopts the grid purchase service mechanism compared with the spot market, AGC and other mature auxiliary service markets."
"The success of the black-start trial can only show that the current energy storage technology has expanded the application scenarios, which does not mean that a new and profitable market can be generated, and in the end, it depends on the comprehensive cost and effect." Zheng Hua further pointed out that the success of the energy storage black start test is only the beginning, and the follow-up also involves the verification of multiple links or steps such as technical reliability, cost economy, market mechanism, and plan process, and there is still a lot of homework to be done before the real application.
With the continuous expansion of the development and application of energy storage technology, the research of black start technology has also accelerated. It is reported that the national standard "GB/T 43462-2023 Technical Guidelines for Black Start of Electrochemical Energy Storage" drafted by China Southern Power Grid, China Electric Power Research Institute and other major units has standardized the overall requirements and technical conditions for black start of electrochemical energy storage, and was officially implemented on July 1 this year.
Original title: What is the prospect of energy storage black start?
Text丨Reporter Lu Qixiu
End
Editor丨Yang Xiaoran