China’s energy resource endowment is dominated by coal. Along with the «double carbon» goal, the demand for low carbon energy production and consumption has become more and more urgent.
In Shaanxi, for example, during the «13th Five-Year Plan» period, Shaanxi Province added a total of 15.13GW of new energy installations; by the end of 2021, the province’s total new energy installations was 24GW. Shaanxi Province’s new energy generation capacity reached 31.124 billion kWh in 2021 (17.638 billion kWh of wind power generation and 13.486 billion kWh of photovoltaic generation), with a new energy utilization rate of 97.5%. According to the 14th Five-Year Plan for National Economic and Social Development of Shaanxi Province and the Outline of Visionary Goals for 2035, the installed capacity of new energy in Shaanxi Province will reach 58 GW in 2025. According to the existing grid peaking resource conditions, it is expected that the utilization rate of new energy will be about 87.5% in 2025. According to preliminary calculations, if Shaanxi Province is equipped with 20% capacity of BESS (2 hours) for the new domestic use of new energy (about 22 million kilowatts) in the 14th Five-Year Plan period, the utilization rate of new energy in the province can be increased to more than 91%.
However, as the utilization rate of new energy increases, the marginal cost of consuming new energy will increase rapidly, and the economics of regulating power sources such as BESS is difficult to guarantee. Northern Shaanxi is rich in solar and wind resources, and is an important area to help Shaanxi achieve low-carbon transformation of electricity, and the power grid in northern Shaanxi has a high proportion of new energy power, and high DC transmission scale. To ensure the safe and stable operation of the grid has become the key.
Therefore, there is an urgent need to explore grid-friendly new energy development technologies, to promote low-carbon power transformation and support safe grid operation.
Economic analysis of Concentrated Solar Power with Storage
CSP with Storage is a grid-friendly new energy technology. Compared with wind power and photovoltaic power generation, it has the advantages of controllable power output and rotational inertia support for the system; compared with thermal power, it has the technical advantages of clean primary energy and more flexible peak regulation performance; compared with battery storage, it has the technical advantages of higher safety and longer energy storage duration. Therefore, the development of CSP with Storage is conducive to alleviating the contradiction between large-scale grid-connected consumption of new energy and safe and stable operation of power system. In the context of «double carbon», the development of solar thermal power plants is one of the ways to promote large-scale new energy consumption.
At present, the main reason why the development of CSP is limited is the high investment cost. According to the information of CSP plants that have been (to be) put into operation, the current investment per unit capacity of CSP plants is 6 to 10 times PV plants. As technology progresses and the scale of construction increases, the investment cost of solar thermal power plants will gradually decline.
By the end of 2020, the installed capacity of operational CSP is 520MW, and 1.11 GW under construction now. It is expected that the domestic installed capacity of operational CSP plants can exceed 1GW in two years and reach 10GW in the next 5 to 10 years. Referring to the relationship between the scale and investment of PV development, it is expected that by 2030, China’s CSP cost can drop by about 40%. At that time, the technical and economic benefits of CSP with Storage will be more obvious when considering its advantages in ensuring the safety and stability of the power grid.
Multi-effort to help the development of CSP with Storage
Northwest China and the Tibet Autonomous Region are rich in solar resources, and have good conditions for the development of solar thermal power plants because of their vast territory and relatively sparse population. Relevant policies also provide good development opportunities for the development of solar thermal and energy storage. From the perspective of grid demand, according to the «14th Five-Year Plan», the northwest region and the Tibet Autonomous Region are important national energy bases, and are «west-east power transmission» continuous transmission areas, and will also build a number of ultra-high voltage DC transmission channels; under the relevant national requirements. DC operation requires CSP with Storage to play an important role in peak regulation, frequency regulation and voltage regulation.
Solar resource-rich regions need to vigorously build CSP with Storage plants, and actively explore grid-friendly new energy technology paths supported CSP with Storage to meet the requirements of low-carbon energy transition and help achieve carbon neutral carbon peaks at an early date.
At this stage, it is recommended that a census of solar resources be carried out as soon as possible. The construction conditions of solar thermal power generation depend on the direct solar radiation resources. It is suggested that each province should carry out a census of solar resources and make a good overall plan for the development of photovoltaic and solar thermal in combination with the distribution of resources, so as to leave space for future solar thermal development.
It is recommended that CSP demonstration projects be restarted. The areas initially determined by each province to have the best direct solar radiation resources can be included in the site selection of demonstration projects; scientifically select suitable types of solar thermal technologies, start demonstration projects as soon as possible, and study and explore key technologies and business models for solar thermal development that meet the conditions of each province.
At this stage, CSP with Storage is still in the early stage of development, and it is recommended that supporting policies be introduced to promote the development of China’s solar thermal industry.
It is recommended that a «quota system» for solar thermal power generation be implemented for the centralized development of new energy sources, and that the coordinated development of photovoltaic power generation, wind power and solar thermal power generation be promoted. In areas with suitable resource conditions, the development and utilization of new energy under optimal technical and economic conditions should be explored in accordance with a certain ratio of solar thermal capacity.