Moderator: Fang Wei, National Grid News Editor
Guest: Director of Renewable Energy Division, Energy Bureau, Shilishan National Development and Reform Commission
Zhao Qingbo, Director of Development Planning Department, State Grid Corporation of China
Xu Honghua, Deputy Director, Institute of Electrical Engineering, Chinese Academy of Sciences
After years of development, photovoltaic power generation has been relatively mature at the technical level, and gradually developed from the independent system in the past to the scale of grid integration.
Moderator: According to the future energy development trend, the development and utilization of solar energy is very popular among many countries in the world. What is the current status of China's photovoltaic industry?
Shi Lishan: At present, mature solar energy utilization technologies are mainly solar photovoltaic power generation and solar water heaters. Solar photovoltaic power generation has the characteristics of mature technology and high cost. It is necessary to give full play to the advantages of solar photovoltaic power generation for decentralized power supply, and to promote users to use photovoltaic power generation systems or build small photovoltaic power plants in remote areas to solve the problem of power supply for non-electricity population. In large and medium-sized cities with more developed economies and higher levels of urban modernization, rooftop solar-connected photovoltaic power generation facilities integrated with buildings will be built. First of all, it should be applied on public welfare buildings, and then gradually promoted to other buildings. At the same time, it promotes the use of photovoltaic power sources in the lighting of public facilities such as roads, parks, stations, etc., providing the necessary market for the development of solar power generation technology.
Xu Honghua: The connection between photovoltaic power generation system and power grid can be divided into two categories: independent photovoltaic system and grid-connected photovoltaic system. After years of development, photovoltaic power generation is currently a relatively mature and reliable technology, and has gradually evolved from the past independent systems to large-scale grid connection. However, the most significant shortcoming of photovoltaic power generation is the high cost. At present, the production cost per kWh of electricity is about 20 times that of coal-fired power and about 10 times that of wind power. According to the development roadmap of the United States, Japan, and Europe, it is expected that with the advancement of technology, the improvement of conversion efficiency, and the expansion of market size, the cost of photovoltaic power generation may be close to the current wind power cost by 2030. In short, solar photovoltaic power generation is currently costly, but the industrialization base is good. It has the technical, cost and environmental advantages to become a strategic energy source around 2030, and can become an important source of energy supply around 2050.
After entering this century, China's photovoltaic market has developed rapidly. In 2002, the state launched the power transmission to the township project in the western provinces and towns. By the end of 2005, a total of 268 small hydropower stations were built in the seven provinces of western China (Tibet, Xinjiang, Qinghai, Gansu, Inner Mongolia, Shaanxi, and Sichuan). And 721 photovoltaic and wind-solar hybrid power stations have solved the basic living electricity problem of about 300,000 households with 1.3 million people. Power transmission to the township project is the largest project in China and the world that has adopted photovoltaic power generation or wind-solar hybrid power generation to realize rural electrification in remote areas without electricity. The implementation of the project has really promoted the development of the domestic photovoltaic industry, and thus created the rise of a large number of domestic PV companies such as Wuxi Suntech, Tianwei Yingli, Changzhou Tianhe, etc., and promoted the talent cultivation and capacity building of China's photovoltaic industry. It has greatly promoted and promoted the development of China's photovoltaic industry.
At present, the proportion of photovoltaic power plants in the power system is very small, and there is no significant impact on the power grid after the grid connection. However, the scale of photovoltaic power plants will continue to increase in the future, we must give full attention to
Moderator: There are not many solar photovoltaic power plants in China, and most of them are distributed power sources, and there is no access system. So, what is the operation status of the existing grid-connected photovoltaic power station?
Zhao Qingbo: At present, there are not many solar photovoltaic power plants, and there are not many parallel grids. For Beijing, the four office buildings of Beijing Street Light Management Center and the roof of Zuo'anmen Hotel are equipped with solar cells. The solar power system is converted into power frequency AC through the inverter and directly connected to the low-voltage power distribution of the street lamp center. The network is currently in good condition. The large-scale photovoltaic power generation projects in Shanghai mainly include Fengxian Bay's 10 kV solar photovoltaic grid-connected power generation system. The system has been connected to the grid for nearly 5 years and is operating well. Because of its small proportion in the system, it does not have much impact on the grid after the grid connection. However, the scale of photovoltaic power plants will continue to increase in the future, and its performance will definitely affect the safe operation of the power grid. Therefore, we must pay full attention to it.
Xu Honghua: Grid-connected photovoltaic power generation technology is the trend of photovoltaic power generation in the world today. Grid-connected photovoltaic power generation is mainly divided into two parts: First, photovoltaic and building integration, which is a typical distributed power supply, the power supply is located at the end of the grid, suitable for urban development; the second is a large-scale photovoltaic power station, mainly built in the desert and Gobi.
In fact, photovoltaic power generation is most suitable for civil buildings in many aspects, and the vast free area outside the building can be used for a long time. At the same time, the electricity produced by the building itself is distributed at the terminal, avoiding network losses. In August 2004, the Institute of Electrical Engineering of the Chinese Academy of Sciences built the photovoltaic power station of the Shenzhen International Garden and Flower Expo Park, the largest grid-connected photovoltaic power plant in Asia at that time, with a grid-connected capacity of 1 MW. At present, the 100 kW grid-connected photovoltaic power generation system of the National Stadium under construction is a true photovoltaic building integrated system. According to the installation method, it will be divided into two parts: one part adopts the conventional crystalline silicon solar cell and is installed on the metal roof; the other part will adopt the double glass solar cell (the solar cell is packaged in the front and rear two layers of high-strength glass) as Part of the glass curtain wall, installed on the south facade of the National Stadium. The completion of the photovoltaic power station will provide a successful example for the combination of urban construction and new energy applications in China, and will also demonstrate the concept of hosting the Green Olympics and the Olympic Games in China.
Moderator: It seems that China has carried out many demonstration work in the field of photovoltaic power generation. At present, does China have the conditions for building grid-connected photovoltaic power plants?
Xu Honghua: An important feature of photovoltaic power plants is integration. Several kilowatt-class power plants can be integrated into one megawatt-scale power station, and several megawatt-scale power plants can be integrated into one tens of megawatt-scale power station. Therefore, large-scale photovoltaic power plants are currently in the early stage of small-scale demonstration, and have not entered industrialization. Another feature of large-scale photovoltaic power plants is high-voltage grid connection. Desert power stations need long-distance power transmission, generally in medium and large scale. Therefore, research on high-voltage grid connection of photovoltaic power generation system is one of the most important issues. In China, the research and construction of large-scale solar grid-connected power generation directly connected to the high-voltage power grid is still a blank. In order to make up for this gap, the Ministry of Science and Technology, the Institute of Electrical Engineering of the Chinese Academy of Sciences and other units have been committed to experimental research in this area. By 2005, both the maturity of technology and the experience of design and construction of personnel have already met the conditions for directly constructing high-voltage grid-connected photovoltaic power generation systems.
Moderator: Solar photovoltaic power station is an unstable power supply, so what is the impact of large-scale grid-connected power stations on the power grid? How does the power grid respond?
Zhao Qingbo: The impact of grid-connected photovoltaic power plants on the power grid mainly includes the following aspects: First, the actual output power of the solar photovoltaic power station changes with the change of the light intensity, the output power is unstable, resulting in voltage fluctuation; the second is the direct current output of the photovoltaic power station. It can be converted into alternating current by the inverter, which will generate a large number of harmonics; the third is that the photovoltaic power station is basically pure active output, and the reactive power balance problem should be considered when connecting the grid. At present, relevant parties have introduced some standards and regulations for grid connection of photovoltaic power plants, and have taken many countermeasures and achieved certain results.
It is recommended that the government price management department determine the on-grid electricity price according to the advanced level and reasonable income level of the photovoltaic power generation project, and regularly publicize it to the public and accept social supervision.
Moderator: To develop health and rapid development of the photovoltaic industry, what problems need to be considered as early as possible or what measures are taken?
Zhao Qingbo: At present, the market price of solar cell semiconductor materials is very expensive. The unit cost in Shanghai is as high as 60,000 to 70,000 yuan per kilowatt, which is 5 to 6 times that of wind power. To vigorously develop solar photovoltaic power generation, it is necessary to strengthen technical research and development efforts and reduce costs. At the same time, it is recommended that the government price management department determine the on-grid electricity price according to the advanced level of the photovoltaic power generation project and the reasonable income level, and regularly publicize it to the public to accept social supervision.
Xu Honghua: At present, the cost of photovoltaic power generation is still relatively high. It is difficult to develop directly according to market rules. Experience in the world proves that the current development of optoelectronics is mainly policy-driven. Most of the grid-connected PV systems installed recently have been residential and public building photovoltaic systems and have received strong government support.
In the planning and development of photovoltaic power plants, it is necessary to give full play to the advantages of solar photovoltaic power generation for decentralized power supply, and to promote household photovoltaic power generation systems or small photovoltaic power plants in remote areas to solve the problem of power supply for non-electricity population. Install solar photovoltaic power generation facilities in urban buildings and public facilities to expand the utilization rate of urban renewable energy and provide the necessary market scale for solar photovoltaic power generation. In order to promote the development of China's solar power generation technology, it is necessary to do a strategic reserve of solar energy technology, and build several solar photovoltaic power generation demonstration power stations and solar thermal power generation demonstration power stations.
It is estimated that by 2020, the integration of photovoltaic buildings will enter the stage of large-scale commercialization and become the focus of the development of the photovoltaic industry. In addition, the desert power station will also become the main energy source in China in the future.
Moderator: Recently, the state officially promulgated the "China's medium and long-term development plan for renewable energy", and proposed the solar industry development plan and goals. Please explain to the experts.
Shi Lishan: In the long term, photovoltaic power generation is still mainly focused on solving the electricity consumption of the non-electricity population in remote areas. Overall, in China's current new energy plan, the country's focus is on wind power generation, and the industrialization of solar energy needs to wait for a while.
Xu Honghua: The National Development and Reform Commission recently released the "China's Medium and Long-term Development Plan for Renewable Energy" clearly stated that by 2010, the total capacity of solar power will reach 300,000 kilowatts, and by 2020 it will reach 1.8 million kilowatts.
The key points in the planning of photovoltaic building integration include: building a solar-powered grid-connected photovoltaic power generation facility integrated with buildings in large and medium-sized cities with relatively developed economies and high levels of modernization, first on public welfare buildings. Application, and then gradually promoted to other buildings, while promoting the use of photovoltaic power in the lighting of public facilities such as roads, parks, stations. During the 11th Five-Year Plan period, the focus was on piloting urban rooftop photovoltaic power generation in Beijing, Shanghai, Jiangsu, Guangdong and Shandong. By 2010, 1,000 rooftop photovoltaic power generation projects will be built nationwide with a total capacity of 50,000 kilowatts. By 2020, 20,000 rooftop photovoltaic power generation projects will be built nationwide with a total capacity of 1 million kilowatts.
It can be seen that in the near-term goal, photovoltaic building integration is not the focus of construction, accounting for only 1/6 of the total capacity of solar power in China. In the long-term goal of 2020, photovoltaic building integration has entered the stage of large-scale commercialization, accounting for about 56% of the total capacity of solar power in China.
The plan for the construction of grid-connected photovoltaic projects in large open areas includes the construction of larger-scale solar photovoltaic power plants and solar thermal power plants. During the 11th Five-Year Plan period, large-scale grid-connected solar photovoltaic power station demonstration projects were built in Dunhuang, Gansu, and Lhasa (or Ali) in Tibet; idle land, Gobi, and wasteland were selected in Inner Mongolia, Gansu, and Xinjiang to build solar thermal power generation demonstrations. project. By 2010, the large-scale grid-connected photovoltaic power station will have a total capacity of 20,000 kilowatts and a total solar thermal power generation capacity of 50,000 kilowatts. By 2020, the total capacity of solar photovoltaic power plants nationwide will reach 200,000 kilowatts, and the total capacity of solar thermal power generation will reach 200,000 kilowatts.
As far as the near-term goal is concerned, large-scale open-grid PV projects have only begun to demonstrate, accounting for only 7% of China's total solar power generation capacity. At present, the technology of solar thermal power generation is not mature enough, and desert photovoltaic power plants may have a larger share before 2020. The desert power station will become one of the main energy sources in China in the future.
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