Wang Zhifeng: Solar thermal power generation can turn the power grid into a true energy internet

China Energy Storage Network: Solar thermal power generation is becoming a rising star in the renewable energy industry. Why is solar thermal power generation a technology that can truly turn the power grid into an energy internet? What role does solar thermal power generation play in this? Compared with other renewable energy sources, what are the unique advantages of solar thermal power generation? What are the current technical difficulties of solar thermal power generation? Are there any good solutions? What is the future technical direction? The first batch of solar thermal demonstration projects have been approved for some time, but the progress does not seem to be smooth. Where do you think the problem lies? How to solve it? In response to the above series of questions, the reporter recently interviewed Wang Zhifeng, director of the Key Laboratory of Solar Thermal Utilization and Photovoltaic Systems of the Chinese Academy of Sciences.

China Energy News: Why is CSP a technology that can truly transform the power grid into an energy internet? What role does CSP play in this process? Compared with other renewable energy sources, what are the unique advantages of CSP?

Wang Zhifeng: The characteristic of energy internet is to make renewable energy stable and continuous, and make power supply dispatchable, mainly for the electricity and heat that can be exported by users. As an emerging renewable energy technology, solar thermal power generation can turn the power grid into a real energy internet by virtue of its advantages such as heat storage, peak regulation, continuous power generation and combined heat and power.

The commercialization and large-scale industrial application of solar thermal power generation is of great significance to promoting energy revolution, promoting energy security, adjusting energy structure, and improving the ecological environment.

First, it can provide basic guarantees for my country's future energy supply and energy security. Solar thermal power generation can not only solve the intermittent shortcomings of photovoltaic power generation and provide basic power support, but also has huge room for cost reduction. Under the general trend of global low-carbon economy and new energy revolution, solar thermal power generation is likely to become the largest alternative energy in my country's future clean development. From the operating principle of solar thermal power stations, it is a storable and adjustable energy source, friendly to the power system, and has peak load regulation capabilities. After breaking through technical barriers, it is an emerging power source that can completely replace coal-fired power stations on a large scale.

Second, it is conducive to improving the environment, reducing greenhouse gas emissions and haze pollution. There is no pollutant emission during the operation of the solar thermal power station, which can directly replace fossil fuels and play an important role in reducing greenhouse gas emissions and controlling air pollution. After the construction of the solar thermal power station, it can reduce the amount of radiation received by the surface soil, slow down the surface wind speed, reduce the evaporation of surface water, and is conducive to vegetation growth and improve the ecological environment.

三是有利于推动风电、光伏发电良性发展。光热发电通过成本相对低廉的储热装置，可成为电力系统友好型电源，既可以承担基荷，也具备较为灵活的调峰能力，可作为未来电网的主力电源。光热发电与光伏发电、风电配套建设，能够显著缓解光伏和风电的出力波动，大幅提高电力系统的消纳能力，减少弃风、弃光问题。

Fourth, it will boost the development of the domestic economy and related industries. The industrial chain of solar thermal power generation is relatively long, involving more than a dozen industries such as steel, aluminum, glass, cement, mineral materials, electrical materials, refractory, insulation, electromechanical, machinery, and electronics. Large-scale development of solar thermal power generation can effectively drive the development of the above industries and become a new fulcrum for economic development. Therefore, solar thermal power generation is not only a clean energy supply solution, but also can increase employment, drive traditional industries, and promote the development of emerging industries.

Fifth, we should enhance my country's international voice and standard-setting power in related fields. Building a solar thermal demonstration power station with independent intellectual property rights, formulating relevant standards, procedures and specifications, and forming a technical system for large-scale development can drive the industrialization and scale of solar thermal power generation equipment, further reduce equipment costs and power generation costs, and "go global" to enhance my country's international voice and competitiveness in solar thermal technology.

China Energy News: What are the current technical difficulties of solar thermal power generation? Are there any good solutions? What is the future technical direction?

Wang Zhifeng: The current technical difficulties of photothermal technology include:

1. Power plant system integration technology

2. Power plant system operation technology

3. Reliability of trough type vacuum heat absorption tube

4. Reliability of high temperature molten salt absorber

5. Reliability of high temperature molten salt heat storage container

Future technology directions:

1. Particle heat sinks: Europe and the United States have made a lot of investment in the research of heat sinks above 7000C, but my country has not, which is out of line with the international development trend. In the future, we may need to promote some major national scientific and technological projects and international cooperation projects to pay attention to this aspect, so as to achieve sustainable promotion of industrialization.

2. Research on equipment reliability, especially molten salt system.

3. In terms of solar energy materials, high temperature coatings, heat transfer and storage materials including fluid gases and solids, and chemical heat storage technology.

4. Research deep water-saving solar thermal power generation technology. Especially BRATON cycle and Stirling cycle technology. EU Horizon 2020 has deployed major projects in this regard, with a funding of 12 million euros. It can be seen that this is an issue that the global CSP community is paying attention to, not just in China. Water conservation is the top priority for the sustainable development of solar thermal power generation.

China Energy News: Multi-energy complementarity is an important direction for future development. How can solar thermal power generation better participate?

Wang Zhifeng: Multi-energy complementarity is not a simple superposition of several energy forms, but a deep integration of multiple energy sources through the coordination of new technologies and new models to achieve the effect of "1+1>2". It can be said that multi-energy complementarity symbolizes a new trend of sustainable energy development. With the maturity of the solar power generation industry and the reduction of costs, the energy industry will form a new generation of energy system with integrated complementarity of multiple energy sources such as solar thermal power generation and basic load.

In addition to solving the problem of wind and solar power abandonment, multi-energy complementarity is also conducive to promoting the development of solar heating and heat supply. Taking winter heating in the north as an example, through the multi-energy complementarity of wind, solar, heat and storage, the heat storage function of solar thermal power generation can be fully utilized to solve the environmental problems caused by coal-fired heating at a lower cost. At the same time, market transactions and price mechanisms will be fully utilized to ensure the economic benefits of the project. Alternatively, through the multi-energy complementarity of other renewable energy sources, each can give full play to its own advantages, better play the advantages of solar thermal power stations, and form a safer, more reliable and more economical new energy system.

China Energy News: In order to seize the initiative and become an important part of the energy internet, what problems does CSP still need to solve? In what directions should it work?

Wang Zhifeng: 1. Technological innovation is an important way to promote the development of solar thermal power generation and an important measure to reduce costs. Therefore, we have fully launched the construction of the first batch of demonstration projects to ensure the reliability of our equipment, technology and operation. We will do our best to complete these projects and prove the technical and economic feasibility of solar power generation.

2. Solar thermal power generation has already been included in the energy internet projects currently announced by the country, and the matching technology between solar power generation and other energy sources in weather forecasting needs to be studied.

China Energy News: The first batch of solar thermal demonstration projects have been approved for some time, but the progress does not seem to be smooth. Where do you think the problem lies? How to solve it?

Wang Zhifeng: In general, there are four main difficulties and problems in promoting the demonstration project:

The initial work of the project involves handling land, forestry, environmental protection, water conservation, grid access, etc. The situation varies from place to place, and some companies have slow progress in handling the formalities.

Technical aspects. There is little experience that can be directly borrowed for CSP projects, and the adaptability of some foreign technologies under my country's environmental conditions needs to be verified; secondly, the process and time of EPC and important equipment bidding and calibration are relatively long; the application and commitment conditions in technical solution optimization and demonstration projects need further research and implementation; finally, the relevant standard methods for key equipment, technology, and operating processes need to be strengthened to reduce communication time.