Recently, the Yumen "Solar Thermal Energy Storage+Photovoltaic+Wind Power" demonstration project with a capacity of 100000 kilowatts, which was contracted and constructed by Northwest Electric Power Design Institute Co., Ltd. (hereinafter referred to as "Northwest Institute") of China Energy Engineering Consulting Group, has obtained a grid connection notice, indicating that the project has the complete start-up conditions and entered the countdown to grid connected power generation. This project is the world's largest molten salt linear Fresnel solar thermal power station under construction. Currently, multiple large energy companies such as Three Gorges Energy, China General Nuclear Power, and China Energy Construction are actively promoting the construction of solar thermal power generation projects.
In order to accelerate the development of solar thermal power generation, in April 2023, the National Energy Administration issued a notice on promoting the large-scale development of solar thermal power generation, proposing to land a batch of solar thermal power generation projects as soon as possible in conjunction with the construction of new energy bases in desert, Gobi, and desert areas. Strive to increase the annual capacity of solar thermal power generation in China to around 3 million kilowatts during the 14th Five Year Plan period. Over a year has passed, and the large-scale development of solar thermal power generation has accelerated significantly.
Newly built and started units increase
When it comes to solar power generation, people usually have a neat and smooth array of solar panels in their minds, which is a common impression of solar power generation. In fact, there is another important form of power generation in the solar power family - solar thermal power generation. Unlike photovoltaics, which directly convert light into electricity, solar thermal power generation technology converts solar energy into heat energy and generates electricity through the process of thermal power conversion. After installing a thermal storage system, solar thermal power generation units can achieve 24-hour continuous and stable power generation, which is an important part of building a new energy system in China.
Solar thermal power generation is generally divided into tower type, trough type, linear Fresnel type, and disc type according to the technology route of concentrated heat collection. At present, among the operating power plants worldwide, the installed capacity of the trough type is the largest, followed by the tower type, and the linear Fresnel type is relatively rare. There are currently no commercially operated power plants using the disc type solar thermal technology.
In order to promote the industrialization of solar thermal power generation technology in China, the National Energy Administration launched the first batch of 20 solar thermal power generation demonstration projects in 2016, with a total installed capacity of 1.349 million kilowatts, opening up the commercialization process of solar thermal power generation in China. However, due to high costs and other reasons, the good development momentum did not continue in the following years.
From the completion of the first batch of solar thermal power generation demonstration projects until approximately 4 years in 2023, there have been almost no new large-scale solar thermal power plants built in China. Northwest Institute is the earliest engineering design enterprise in China to carry out research and development of solar thermal technology, with solar thermal power generation projects accounting for over 70% of the country's total. According to Gao Hongqi, General Manager of Northwest Institute New Energy Engineering Company, with the release of a series of new policies by the National Energy Administration and provinces such as Xinjiang, Gansu, and Inner Mongolia last year to support the construction of solar thermal power generation, the number of newly built and started solar thermal power generation units in China has significantly increased.
Du Fengli, Secretary General of the National Solar Thermal Industry Technology Innovation Strategic Alliance, introduced that as of the end of 2023, there are over 40 solar thermal power generation projects under construction or planned in various provinces of China, with a total installed capacity of about 4800 megawatts. It is expected to be completed by 2025 at the latest, of which about 1200 megawatts are expected to be completed by 2024.
As the scale of this batch of solar thermal power plants grows, their distribution area becomes wider and they place greater emphasis on peak shaving. This batch of solar thermal power stations is mainly planned and implemented in sync with the Wind Power Development Base. Solar thermal power stations are indispensable regulatory power sources in these bases, "said Li Jianfeng, the project manager of the Yumen Solar Thermal Project at Northwest Institute. Taking the Yumen" solar thermal energy storage+photovoltaic+wind power "demonstration project as an example, after the overall project is completed, the annual grid connected new energy power generation will be about 1.75 billion kilowatt hours, which can effectively solve the problem of power abandonment faced by large-scale development of new energy bases and has important demonstration significance for building a new type of power system.
The reporter noticed that unlike the first batch of demonstration solar thermal power plant investment entities mainly consisting of solar thermal technology and equipment enterprises, the investment entities in this batch are mostly traditional power investment enterprises, such as Three Gorges Group, National Energy Group, Datang Group, China General Nuclear Power, China Energy Engineering, China Power Construction, etc.
Gao Hongqi told reporters that the main motivation for the first batch of enterprise investments is to develop new technologies and explore new fields. The purpose of the new batch of enterprises investing in the construction of solar thermal power plants is more to support the healthy development of their own photovoltaic or wind power businesses and to achieve the "dual carbon" goal.
Enhanced industrial supporting capabilities
Behind the large-scale development of solar thermal power generation is the gradual improvement of the industrial chain and the continuous reduction of costs.
The solar thermal industry has already met the conditions for large-scale development, "said Zhao Xiaohui, Vice Chairman of the National Solar Thermal Industry Technology Innovation Strategic Alliance and General Manager of the Northwest Institute Science and Technology Innovation Center. China's solar thermal industry chain system covers every link from raw materials to core equipment with independent intellectual property rights, including steel, cement, ultra white glass, high-temperature heat absorption and transmission materials, insulation materials, tower type heliostats, tower type heat absorbers, trough collectors, high-precision transmission boxes, on-site controllers, sliding pressure turbines, etc. In the first batch of national solar thermal power generation demonstration projects, the reliability and progressiveness of domestic technology and equipment have been effectively verified after the power station is put into operation.
In the view of Li Guangming, Deputy Secretary of the Party Committee and General Manager of China General Nuclear Power New Energy Holdings Co., Ltd., since the 14th Five Year Plan period, the independent innovation capability of China's solar thermal industry has significantly improved. Through the operation practice of the first batch of solar thermal demonstration projects, China has basically mastered the core technology of solar thermal power generation and the operation and maintenance technology of solar thermal power plants that are suitable for the high-altitude and high-altitude environment in China, and has the ability to manufacture key equipment.
According to incomplete statistics, there are about 600 supporting enterprises related to solar thermal power generation projects in China, with a localization rate of over 90% for equipment and significantly enhanced industrial supporting capabilities, laying a solid foundation for the large-scale development of solar thermal power generation technology in the future.
Lower costs also provide a prerequisite for the promotion of solar thermal power generation. The "China Renewable Energy Engineering Cost Management Report 2023" recently released by the Water Resources Planning and Design Institute shows that the cost of early solar thermal power generation projects is generally high, with a total investment of 24000 to 35000 yuan per kilowatt. Recently, the unit cost of the project has significantly decreased compared to the early stage, with a total investment of 13500 to 23000 yuan per kilowatt.
The unit cost of converting this batch of solar thermal power stations to per kilowatt capacity has significantly decreased, "Zhao Xiaohui analyzed. This is mainly due to the change in the function of solar thermal power stations in the power system, from the previous independent power source of" generating as much as possible "to" energy storage peak shaving ", and the absorption of abandoned electricity by supporting new energy power stations, resulting in a significant reduction in the scale of the concentrating system. In addition, major equipment such as the mirror field, three main machines, and molten salt tanks have all been localized, resulting in a significant decrease in equipment prices. In addition, the technological progress of upstream industries and the increasingly fierce commercial competition have driven the reduction of system technology costs.
Some institutions predict that if a certain market and industry scale are maintained, with the decrease of equipment and construction costs, the cost of solar thermal power generation in China can achieve a significant reduction. It is expected to be comparable to the cost of gas-fired power generation by the end of the 14th Five Year Plan period, that is, the electricity price will be reduced to 0.7 yuan/kWh to 0.8 yuan/kWh, and further reduced to around 0.5 yuan/kWh by 2030. At that time, considering its advantages such as flexible heat storage, adjustable output, and ability to provide rotational inertia, it will have economic viability and competitiveness in the electricity market.
Core technology still needs improvement
The "dual carbon" target has brought huge development space for solar thermal power generation and once again boosted industry confidence. But whether the new wave of investment in solar thermal power generation can be sustained still depends on a series of challenges such as core technologies.
At present, the main factor restricting the sustainable development of solar thermal power generation in China is the lack of continuity in relevant policies. For example, after the National Development and Reform Commission approved the benchmark grid connected demonstration electricity price for solar thermal power generation in 2016, the enthusiasm for enterprise construction has been high; The "Several Opinions on Promoting the Healthy Development of Non Water Renewable Energy Power Generation" issued at the beginning of 2020 clearly stated that newly added solar thermal projects will no longer be included in the scope of central financial subsidies, and the development momentum of solar thermal power generation will be significantly affected.
Li Guangming believes that the market positioning of solar thermal power generation technology is unclear, and the price mechanism is not yet sound. The "solar thermal+" integrated base projects under construction in China mainly rely on a high proportion of wind power and photovoltaic installed capacity to configure a certain amount of solar thermal installed capacity. However, solar thermal installed capacity is limited by the investment economy of grid parity, and the proportion of installed capacity is relatively low, which is not enough to play the supporting role of solar thermal units in the power grid. At the same time, the current financing environment and related policies cannot provide strong support for the healthy development of solar thermal power generation.
Experts say that with the momentum of promoting the large-scale development of solar thermal power generation, it is necessary to encourage regions with conditions to study and formulate supporting policies to support the large-scale development of solar thermal power generation as soon as possible. The energy regulatory authorities in key provinces such as Inner Mongolia, Gansu, Qinghai, and Xinjiang should actively promote the planning and construction of solar thermal power generation projects, coordinate the layout of photovoltaic and solar thermal planning, and synchronously promote the scale and industrialization development of solar thermal power generation projects in the construction of new energy bases.
According to the reporter's understanding, the second-generation solar thermal power generation technology using molten salt as the heat transfer and storage medium is currently the main technology. Although engineering demonstrations have been carried out, the reliability and lifespan of the core equipment need to be improved. The high cost of concentrating and energy storage equipment restricts the development of solar thermal technology.
Zhao Xiaohui stated that the cost of concentrators accounts for about half of the total investment in solar thermal power plants, and in the future, the focus should be on improving the accuracy of concentration and reducing the overflow loss of heat absorbers. At present, the development of key component production line technology, including concentrators, is slow in China. It is necessary to improve product quality control technology and processes in large-scale practice, optimize the production lines and processes of concentrator, heat absorbing, and heat transfer components. Simultaneously conducting research on million kilowatt level electricity/heat conversion methods to reduce unit cost through economies of scale.
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Article source: Economic Daily