A preliminary study on the transmission and distribution price system adapting to the development of new power system

China Energy Storage Network: With the frequent occurrence of various natural disasters and extreme weather events around the world, climate issues have received increasing attention from governments and people around the world, and carbon emission reduction and global climate governance have become the consensus of the international community. In September 2020, President Xi Jinping pledged at the general debate of the 75th United Nations General Assembly that China's carbon dioxide emissions will strive to reach a peak before 2030 and strive to achieve carbon neutrality before 2060. The 9th meeting of the Central Financial and Economic Commission in March 2021 made important arrangements for the implementation of the "dual carbon" goals, and proposed to build a new power system with new energy as the main body, which pointed out the direction for the transformation and development of China's energy and power under the background of "dual carbon". Building a new power system with new energy as the main body requires accelerating the energy supply revolution and accelerating the development of new energy such as wind power and solar power generation. It is an extension of the connotation of China's new national energy security strategy of "four revolutions and one cooperation" in the new development stage. Promoting low-carbon and green development by promoting energy structure optimization is an important measure to implement the commitment to building a community with a shared future for mankind, and it provides a "Chinese solution" to respond to global climate change and promote global climate governance.

The new power system of the future will have the morphological characteristics of high-proportion new energy access, flexible and reliable resource allocation of highly elastic power grids, diversified interaction of highly electrified terminal loads, and digital empowerment of multi-network integration of infrastructure. The existing power system will also evolve in multiple dimensions, from a deterministic system to a highly uncertain system, from electromechanical equipment dominance to power electronics equipment dominance, and from a single power system to an integrated energy system. The above morphological characteristics and evolution will have a profound impact on the power system and transmission and distribution prices.

The impact of new power system construction on power system

Impact on power generation

By the end of 2020, the cumulative installed capacity of wind power, photovoltaic and other new energy power generation in my country reached 535 million kilowatts, accounting for about 24.3% of the country's total installed capacity; the annual power generation of new energy reached 727.6 billion kilowatt-hours, accounting for about 10% of the country's total power generation. Under the "dual carbon" goal, the construction of a new power system will promote the leapfrog development of new energy in a centralized and distributed manner. The proportion of new energy installed capacity and power generation will increase significantly, and it will occupy a dominant position in the installed capacity and power supply of the power system. According to relevant research forecasts, by 2030, the proportion of wind power and solar power will reach about 50%; by 2050, the proportion of new energy power generation will exceed 50%; by 2060, the proportion of new energy power generation will exceed 82%.

By then, new energy will not only become the main body of the safe and stable operation of the new power system, but will also have certain active support, system adjustment and fault crossing capabilities, so as to basically achieve the balance of the power system and avoid the increase in power supply costs caused by the need for other power sources to provide system balancing services. The construction of pumped storage power stations, hydrogen energy and energy storage facilities can enhance the system's flexible adjustment capabilities and improve the new energy consumption and storage capabilities. The proportion of traditional fossil energy power sources will continue to decline, gradually shifting from basic power sources to regulating power sources, mainly providing bottom-line protection, regulation and support functions for the power system, and gradually withdrawing in the long term.

Impact on the power grid

The traditional power system is mainly based on the large power grid mode, and the power consumption on the load side cannot be freely controlled. Therefore, a real-time balancing mode of "source follows load" must be adopted, that is, a controllable power supply is used to match the load changes, and rolling adjustments are made during the actual operation process, so as to achieve safe and reliable operation of the power system. Correspondingly, an integrated control mode must be adopted in the control link of the power system. However, in the new power system with new energy as the main body, new energy such as wind power and photovoltaics are characterized by volatility, randomness, and intermittency. The traditional power grid operation mode can no longer meet the needs of the operation of the new power system. The power system balance mode will also shift to a non-complete real-time balance with coordinated interaction of source, grid, load and storage. The corresponding control mode will also shift to coordinated control of large power grids and microgrids.

In the future new power system environment, the transmission and distribution network will undergo significant changes. On the one hand, since my country's new energy resource endowment is mainly distributed in the "Three Norths" region, and the load centers are mainly distributed in the eastern and southern regions, the large-scale consumption of new energy must be carried out over long distances, so it is necessary to invest in and build large-scale long-distance transmission channels; on the other hand, in order to meet the access of distributed new energy, new energy storage facilities, electric vehicles and various types of controllable loads, it is necessary to improve the carrying capacity and flexibility of the distribution network, develop and build an active distribution network (ADN), improve the power quality of the distribution network, and improve the absorption capacity of new energy. At the same time, the massive data and extensive connections under the new power system make the digital grid based on the organic integration of digital information and physical systems a reality, and become the best form to carry the new power system, making the power grid safer, smarter, more efficient and low-carbon. All of these will undoubtedly lead to an increase in the scale of investment in the transmission and distribution network.

Impact on load chain

Under the background of "dual carbon", the load side of my country's power system will face more uncertainties in the future. On the one hand, the construction of a new power system will inevitably start a new round of electrification. Many fields such as industry, transportation, and construction will promote the substitution of electric energy, replacing traditional high-carbon energy with clean and low-carbon electric energy, and electric energy will gradually become the most important energy consumption variety. According to the prediction of relevant research, by 2035 and 2060, the proportion of electric energy in terminal energy consumption will reach 45% and 70%. Therefore, the growth of electricity in the future will be an inevitable trend. In this process, due to the growth of various types of electrical equipment, the load characteristics of different equipment are also very different. In particular, some loads have the ability to actively participate in system regulation, and the factors affecting the load have also increased accordingly. The uncertainty of the load has also increased accordingly, and the balance mode of "source follows load" of the traditional power system will be difficult to sustain.

On the other hand, the “dual control” policy of energy consumption under the “dual carbon” goal will also bring greater uncertainty to the electricity consumption and growth of high-energy-consuming industries, and bring greater difficulties to the power balance of the entire system. Combining the above two factors, the complexity and difficulty of load forecasting under the new power system will be much higher than that of the traditional power system.

Adapting to the development of new power systems

Analysis and suggestions on transmission and distribution price system

At present, my country's transmission and distribution price supervision mainly follows the principle of "reasonable cost and reasonable profit", and forms the transmission and distribution price structure and level with the goal of fair sharing of transmission and distribution permitted income. With the construction of new power systems, more and more new energy sources will be connected to the power system in the future. At this time, the formulation of transmission and distribution prices also needs to consider how to promote the consumption of new energy sources, while avoiding or reducing the increase in electricity prices caused by the construction of new power systems. Therefore, future transmission and distribution prices need to seek breakthroughs in optimizing the price structure and innovating the price mechanism to achieve the above goals.

Optimization of electricity price structure

First, the development of large-scale centralized new energy has put forward more demands for grid access and backbone grid construction and expansion, while the development of massive distributed new energy requires investment in the construction of a stronger and more flexible distribution network. Therefore, in order to adapt to the large-scale access of new energy, centralized and distributed, it is inevitable to bring new and additional transmission and distribution network investment needs. Based on the principle of "who benefits, who pays", the costs and expenses brought by the above investment should be borne by the connected power generation enterprises in the form of "access fees". However, in order to encourage the development of new energy, my country has clearly required in many policies that the access fees for new energy power generation facilities should be borne by the power grid, that is, included in the permitted income of the power grid enterprises, and shared by all end users through the common network transmission and distribution price. In the early stage of new energy development, due to its relatively small installed capacity and access scale, the relevant costs of access projects are relatively low, and the impact on the overall transmission and distribution price level and end users is relatively small. Therefore, it is indeed an effective policy to reduce the investment and construction costs of new energy. However, as the scale of new energy installation and access gradually expands, and even develops into the main type of power supply in my country, if the access costs are still borne entirely by end users, it will significantly increase the overall transmission and distribution price level, bringing a greater burden to end users; secondly, it will not be conducive to achieving fair competition for new energy in the electricity market.