China's CSP formally entered the era of commercialization

Solar thermal power generation is becoming a new competition point for China's energy giants. The commercialization of this industry has thus opened the curtain.

Gradually becoming a hot spot for investment The 10kW disc solar concentrating photovoltaic power generation system prototype independently developed by China has been tested and commissioned in Shizuishan City of Ningxia recently, filling the gap in China's disc solar concentrating power generation technology.

Prior to this, in June 2007, the first 70-kilowatt solar tower solar thermal power generation system in China passed the appraisal and acceptance in Nanjing. In July 2010, Asia’s first tower solar thermal power station was built in Yanqing, Beijing.

In April 2011, the successful results of the 50 MW trough solar project in Inner Mongolia were announced. Datang New Energy Co., Ltd. won the bid at the lowest price of 0.9399 yuan/kWh. According to relevant data, the total investment of the CSP project in Inner Mongolia is about 1.6 billion yuan, and it can generate more than 120 million kilowatt-hours per year. Ma Shenghong, a researcher at the Institute of Electrical Engineering of the Chinese Academy of Sciences, said that this is China's first concession project for solar thermal power concessions. This tender is a "zero breakthrough."

On June 1st, the “Guidance Catalogue for Industrial Structure Adjustment (2011 Edition)” promulgated by the National Development and Reform Commission was formally implemented. Among the new energy categories encouraged in the Catalogue Encouragement category, solar thermal power generation was placed in a prominent position. Industry insiders believe that the CSP market is about to usher in a new round of competition.

At present, China is dominated by thermal power generation and has a huge negative impact on the ecological environment. With the deteriorating ecological environment and the depletion of disposable energy such as coal and natural gas, solar power has become a hot spot for new energy sources because of its green, pollution-free and sustainable characteristics.

According to Shen Wenzhong, director of the Institute of Solar Energy Research at Shanghai Jiaotong University, China is one of the countries with abundant reserves of solar energy resources. The area with more than 2000 hours of sunshine hours per year accounts for more than two-thirds of the country's total area. The conditions for the development of solar power plants have an area of ​​desert and Gobi of approximately 300,000 square kilometers, accounting for 23% of the country's total desert area. Solar power has great potential for development in China.

Solar thermal power generation is a new type of solar power generation after photovoltaic power generation. It is a new type of solar industry. At present, although this industry is still in its infancy in China, it is an important direction for the use of new energy.

Over the past year, several major energy companies have started to build several solar thermal power projects in Sichuan, Qinghai, Gansu and Ningxia, ranging from 100MW to 500MW. Wang Haisheng, Chief Analyst of Huatai United Securities New Energy Industry, introduced that at present, Datang has begun to operate different scales of CSP in Inner Mongolia, Guodian in Xinjiang, Huadian in Qinghai, and Huaneng in Tibet.

It is understood that the prototype of the 10 kW dish solar concentrating photovoltaic power generation system that has begun trial operation in Shizuishan was independently developed by Zhejiang Huayi Kangdis Solar Technology Co., Ltd. Wan Bin, chief executive of the company, introduced that this solar concentrating power generation system uses a combination of new technologies, new materials, and new processes, which is only half a year later than the United States. Compared with other solar power generation systems, this set of disc concentrating The photoelectric conversion efficiency of the power generation system reaches more than 30%, and it has the advantages of flexible installation, low manufacturing and maintenance costs, and a broad market prospect. In August this year, the company will also launch a 25kW solar concentrating power system.

What is solar thermal power? The principle of solar thermal power generation is to use a large-scale array of parabolic or dish-shaped mirrors to collect solar thermal energy, provide steam through heat exchange devices, and promote traditional turbine generators to generate electricity. Solar thermal power generation technology and silicon photovoltaic power generation, the former can greatly reduce the cost of solar power generation. Moreover, this form of solar energy utilization has an advantage that other forms of solar energy conversion cannot match: solar hot water can be stored in huge containers and can still drive steam turbines for several hours after the sun goes down. Power generation.

CSP has three types of systems: trough, tower and dish.

Trough solar thermal power generation system is called: trough type parabolic reflector photothermal power generation system, which arranges several parabolic trough concentrator collectors in series and in parallel to collect heat and boil water to produce high-temperature steam to drive steam turbines to generate electricity. The unit generates electricity.

In the 1970s, solar cells were expensive and inefficient. Relatively speaking, the efficiency of solar thermal power generation was relatively high and the technology was relatively mature. At that time, many industrialized countries focused on solar thermal power generation and invested in a number of pilot projects. Solar thermal power station. According to incomplete statistics, from 1981 to 1991, there were about 20 solar thermal power stations (500 kW or more) built around the world, and the maximum generating power was 80 MW. In the early 1980s, Israel and the United States began to study trough parabolic concentrator solar thermal power generation systems. From 1985 to 1991, 9 trough solar thermal power stations were successively built in the California desert of the United States, with a total installed capacity of 353.8 MW, which was incorporated into the network operation. After hard work, the initial investment in the power station was reduced from $4,490/kW for the No. 1 power station to $2,650/kW for the No. 8 power station, and the cost of power generation was reduced from 24 cents/kWh to 8 cents/kWh.

From 1981 to 1991, various types of MW-level solar thermal power generation test power stations with installed capacity of 500 kW or more were built around the world, of which the main form was a tower-type power station, and the maximum power generation was 80 MW.

The dish solar thermal power generation system is composed of a parabolic mirror composed of a number of mirrors, and is received at the focus of the paraboloid. The heat transfer medium in the receiver is heated to about 750° C. to drive the engine to generate electricity.

In the past, China was limited by the funding and technical conditions in the field of solar thermal power generation and the work carried out was relatively small. In the "6th Five-Year Plan" period, only a solar tower thermal power simulation device with a power of lkW and a flat panel solar thermal power simulation device with a power of lkW were established. In addition, China also cooperated with the United States to design and prototype a prototype of a dish-type solar power plant with a power of 5 kW.

In the mid-1980s, after a technical summary of the completed solar thermal power stations, it was concluded that although solar thermal power generation is technically feasible, the investment is too large and it is very difficult to reduce the cost, so countries have changed their original plans. Therefore, the construction of solar thermal power stations has gradually cooled down.

Ma Shenghong told reporters that compared to several forms of solar thermal power generation systems, the trough thermal power generation system is the most mature and commercialized development technology. The maturity of tower thermal power generation systems is currently inferior to that of parabolic trough thermal power generation. Although the parabolic dish-type thermal power generation system equipped with Sterling generators has relatively good performance indicators, it is still mainly used for small-scale independent power supply in remote areas, and the large-scale application of mature power is less satisfactory. In addition, although the trough technology is relatively mature, but the power generation process requires a lot of water; tower technology also requires a lot of water; only disc technology 1 kilowatt-hour electricity only 1.4 liters of water, can adapt to the long hours of sunshine in the desert and the Gobi region, in The highest conversion rate is among the three types of CSP technologies.

It should be pointed out that the trough, tower, and saucer solar thermal power generation technologies are also valued by various countries in the world and are actively working.

The lack of commercialization of integrated experience At present, Chinese scientists have studied dish-type power generation systems, tower-type power generation systems, and trough-type condenser units, and mastered a number of core technologies for solar thermal power generation, such as high-precision, high-reflectivity reflections. Mirror, high-precision two-axis tracking control system, heat transfer under high heat flux, solar thermoelectric conversion system, etc.

To improve the efficiency and normal operation of the trough CSP system, two aspects of control issues are involved: First, the automatic tracking device requires the concentrator to be aimed at the sun at all times to ensure maximum solar energy absorption from the source. Statistics show that tracking is 37.7% higher than non-tracking energy. The second is to control the temperature and pressure of the heat transfer liquid circuit, meet the requirements of the steam turbine, and achieve the normal power generation of the system. For these two issues, scholars at home and abroad have conducted research and made some progress.

Research and development of the trough solar medium and high temperature heat utilization system jointly developed by the Institute of New Energy Application Technology of Texas Huayuan and the Institute of Electrical Engineering of the Chinese Academy of Sciences, Tsinghua University, etc. The equipment has a simple structure, easy installation, and an overall service life of up to 20 years. In trough solar thermal power systems.

The most important feature of the high-temperature solar heat utilization system in the trough solar energy is that the solar reflector is fixed on the ground, so it can not only resist the erosion and destruction of wind and rain, but also greatly reduce the cost of the reflector bracket. More importantly, this equipment technology breaks through the limitations of the previous set of control devices that can only control one mirror and can track hundreds of mirrors simultaneously to focus hundreds or thousands of square meters of sunlight onto light energy. Conversion parts (concentration about 50 times, can produce 300 ~ 400 °C high temperature), changing the past, the entire construction cost of most of the tracking control system costs the situation, making it only a small part of the entire project cost.

At the same time, the system adopts localized production of heat collection core components—specular reflective materials and high-temperature direct-fired solar power pipes, which reduces the cost and reduces a lot of costs in transportation and installation costs.

These two breakthroughs have completely overcome the technical obstacles that have long hampered the large-scale application of high-temperature systems in solar troughs, and opened up a broad road for realizing the standardization and large-scale industrialization of high-temperature solar energy equipment manufacturing.

Although China's commercialization demonstration project for CSP has already started, people in the industry still believe that for the enterprise, past R&D was aimed at a single device, and the biggest flaw lies in the lack of experience in system-integrated solar CSP projects.

How to build China's solar thermal power generation industry chain?

Ma Shenghong believes that although the CSP system does not have a high technical threshold for domestic enterprises, domestic companies still need to tackle further problems in the hot oil cycle, energy storage, and heat exchange technologies. The key is the technology of large-scale systems and Experience. At present, it is necessary to break through three bottlenecks: First, it is necessary to grasp the key component technologies and pass the assessment of commercial practices; second, the lack of experience in the construction and commissioning of large-scale power generation systems requires cooperation with foreign companies and experts; third, the current bid price Low, hope that the country can have supportive policies to allow enterprises to have enthusiasm, at the same time have specific requirements for site selection and planning of the power station, early layout and early measurement.

A research report from China International Engineering Consulting Company pointed out that since the cost of solar thermal power generation is still higher than that of conventional power plants, the key to the promotion of solar thermal power generation technology is the need for government guidance and support in policies. Experts suggest that the state should consider giving Chinese companies the opportunity to integrate power plants. Domestic companies will complete the entire industry chain as long as they complete 3 to 4 commercial projects.

The new round of competition is about to emerge. The CSP is proven and reliable power generation technology. In the 1970s, the oil crisis in the Middle East ushered in an opportunity. It was initially applied by the United States in the 1980s and the installed capacity reached 354 MW. Since then, it has experienced the "market gap" period of nearly 20 years. At present, the outbreak of the second market competition has already been "struck".

According to Wang Haisheng, chief analyst of Huatai United Securities New Energy, the first incentive for the FIT of renewable energy in Spain in 2009 prompted the rapid development of its CSP power generation, with a cumulative installed capacity of approximately 582 MW. The project under construction exceeded 600 MW; Incentive policies also prompted the restart of its CSP market, with projects under construction of nearly 500 MW and planned projects exceeding 10 GW (10,000 MW). In addition, Middle East, Australia, India, South Africa and other countries, and markets with varying sizes are also in the process of starting. At present, the global thermal power generation projects under construction and planning have reached 23GW, and the corresponding investment has exceeded 50 billion U.S. dollars.

China also regards solar thermal power generation as one of the key emerging strategic emerging industries. In the “12th Five-Year Plan” of the national power industry, it is clearly stated that during the “Twelfth Five-Year Plan” period, conditions will be selected in Gansu, Ningxia, Xinjiang and Inner Mongolia. Location, construction of solar thermal power demonstration power station. According to statistics of Huatai United Securities, if all the announced projects can be implemented, by 2015, China's installed installed capacity of solar thermal power will reach 3GW, and the total market will reach 45 billion yuan in accordance with the comparable cost of the photovoltaic system.

Photovoltaic solar energy will promote the development of solar energy at the same time. There is no doubt that it is necessary to discuss only the path problem. Is it the development of photovoltaic or solar thermal? The two voices have been controversial. From the initial bias toward photovoltaics, they have evolved into a trend that is currently evenly matched.

Hu Xuehao, deputy chief engineer of the China Electric Power Research Institute believes that solar thermal power generation is the same as thermal power generation through steam turbines, and solar thermal power generation with thermal storage systems is more conducive to the stability and regulation of the power system. At present, the cost of solar thermal power generation is the same as the cost of photovoltaic power generation, but there is no thermal storage equipment for photovoltaic power generation, and solar thermal power generation can use thermal storage devices to provide stable power output. If thermal storage is considered, the integrated price of CSP is cheaper than PV. Moreover, solar thermal power generation is suitable for a variety of technical applications. For example, it can realize low-cost energy storage and improve the power output quality; it can combine with existing power facilities to generate electricity; waste heat from solar thermal power can be used in refrigeration, seawater desalination or sewage purification and other fields.

Today, in various new energy forums, the development prospects of photovoltaic power generation and solar thermal power generation are discussed. In fact, the best development methods for photovoltaics and solar thermal are collaborative development in different fields. For example, photovoltaics are used for small, distributed, one-to-one power generation, and even thin-film battery types for buildings. Photothermal heat is used in large-scale power plants. . The cost of light and heat is relatively low. The larger the installed capacity, the lower the power generation cost, and the scale can be achieved. It can be seen that the industrial chain of solar energy utilization will be more complex and diversified, and the solar industry will continue to develop with great progress while facing more challenges.

Solar thermal power generation has been highly praised by experts in the industry for its good compatibility with existing power grids, high photoelectric conversion rate, continuous stable power generation and peaking power generation capability. People in the industry generally believe that photovoltaic and solar thermal power generation all have good prospects. The two are not alternatives to each other, but parallel development. Under the general trend of the global low-carbon economy and new energy, light-heating electrodes may become the most dominant energy source in China's future.