Wang Zhixuan: Boundaries, variables and barriers of large-scale application of energy storage

Recently, Wang Zhixuan, Vice President of CEC and President of Electric Vehicle and Energy Storage Branch of CEC, received an exclusive interview on energy storage by the reporter of China Electric Power Enterprise Management.

Q: The transformation of low-carbon energy centered on electricity has swept the world, and the role and value of energy storage have become increasingly prominent. What do you think are the trends of energy and power industry related to energy storage? What development opportunities will these changes bring to the energy and power system and energy storage industry?

Wang：From the perspective of the overall power system and its ·operation mode, China’s power system has gradually shifted from a traditional centralized power grid with a vertical integration of generation sources, power grid and load to a model where large power grids with UHV as the backbone and distributed power systems are developing equally. The integration of power supply, transmission, and consumption continues to increase. The traditional boundary between producers and consumers is gradually blurred. New technologies and business models, such as microgrid including energy storage, virtual power plant and electric vehicle charging facilities, are emerging in the cross integration of generation sources, power grid and load.

At present, one of the most important goals of the development of China's energy and power industry is how to provide more stable, more economical and cleaner energy for people. This is not only the goal that China pursues, but also the basic goal pursued by countries in energy transition all over the world. In the triple target structure of low carbon, security and economy, the role of energy storage is to promote and maintain the balance among the three.

Q: Recently, the government document that requires newly built new energy generation projects must equip with matching energy storage capacities have triggered heated discussions in the industry. Does this also define the development positioning of energy storage industry in the future?

Wang: At present, the main application field of energy storage in China is to adjust and suppress the volatility of the power system. The core task is to promote safe and stable power supply under the development of new energy, whether on the generation source side, on the grid side, or on the load side. From the overall goal of energy transition and the goal of medium and long-term high-quality development of China's power industry, energy storage also plays an important role in seasonal power balance. Obviously, for different energy storage technology and scale, the policy support is different, and the business model is also different.

In the process of energy transition and low-carbon development, it is inevitable to have disputes, which are normal and necessary. The implementation of the document is an effective exploration to solve the problems existing in the development of new energy, which has already gained some practical international experience in the United States and other countries and regions. However, whether such a model can be continued, or whether it can be popularized nationwide, should be analyzed according to local conditions.

Q: In your opinion, what variables, boundaries and barriers still exist if energy storage as the "upstart" of the system wants to become "mainstream"?

Wang: At the present stage, the application of energy storage technologies has superior technical competitive advantages in certain areas, specific scenes and specific time periods. However, generally speaking, the economy of energy storage does not have the ability to compete with other power system adjustment instruments. If energy storage wants to "break through the encirclement" and become the "mainstream", it needs to realize self-breakthrough in terms of high substitutability.

First of all, in the power supply side, the coal-fired power units with the largest proportion in power supply structure is flexibly modified. By reducing the minimum output of power units, increasing the maximum power load gradient and shortening the start-up time, the coal-fired units now has good regulation performance in peak load regulation and frequency regulation, which is equivalent to the flexible adjustment method of energy storage in function.

Secondly, on the power grid side, by increasing the interconnection of regional power grids and making the best of the "indirect energy storage system" of adjacent power grids, the goals of optimizing resource allocation and reducing overall system costs can be achieved at the same time. Therefore, as an important part of China's "new infrastructure", the construction of UHV power grid can potentially enhance the capacity and role of power grid "energy storage". However, the extent to its function depends on the stage of China's power market construction and the extent to which market means can play a role in the optimal allocation of resources.

Thirdly, on the load side, improving the adjustability of the load through technical means such as demand response and realizing the effective interaction between the power demand side and the power grid is a flexible adjustment method with lower overall system cost and more commercial value prospects. With the development of smart grid and communication technology, technologies such as electric vehicle charging pile and user side virtual power plant will make the contribution to the system from the current "peak load shifting" to the effective interaction among "generation sources, power grid and load".

Today, countries all over the world have carried out energy and power industry transition characterized by low-carbon, security and economy. From the experience of international energy transition, we can conclude that the low-carbon transition always means a certain economic cost, but the cost must be in line with the current national economy's affordability. In China, the inevitable constraint factor of energy storage development is the "external barrier" of end-use electricity price.

Q: With the development of electric vehicle industry in recent years, the cost of electrochemical energy storage has been rapidly reduced, and the cumulative installed capacity of electrochemical energy storage in China has also risen to the second place in the world. In your opinion, according to the current development status of international and domestic energy storage industry, what experiences can we summarize that are meaningful to the future development?

Wang: In terms of the development trends, with the substantial increase of the installed capacity of electrochemical energy storage systems, especially the rapid development of grid-side energy storage requirements, it indicates that intensification, aggregation, and platform-based operation will become the main trends in the future. When energy storage is connected to the grid for dispatching, it means that new requirements are put forward for the establishment of standards and standardized system for energy storage power stations in the areas of access, monitoring, dispatching and operation.

The development of the standard system needs to reflect the logical framework of different levels from the macro to the micro levels. We need to continuously carry out the publicity and implementation of energy storage standards, so that more users and equipment providers can realize the technical differences between power system and electric vehicle for energy storage application, and realize the benefits and necessity of adopting energy storage technology standards.