Comparison and Analysis of Photothermal Power and Photovoltaic Power Generation

Solar thermal power generation refers to the use of large-scale arrays of parabolic or dish-shaped mirrors to collect solar thermal energy, provide steam through heat exchange devices, and combine conventional turbine generator technology to achieve power generation. China's solar thermal power generation technology started relatively late. On June 1, 2007, the first 70-kilowatt solar tower solar thermal power generation system in China passed the appraisal and acceptance in Nanjing. On July 1, 2010, Asia's first tower solar thermal power station was built in Yanqing, Beijing. With the country’s increasing emphasis on renewable energy, the development of the CSP industry is very rapid.

In the following, the author briefly compares the solar thermal power generation with the current conventional photovoltaic power generation for a brief comparative analysis for the industry to discuss.

1, the principle of power generation is different.

Conventional photovoltaic power plants use solar panels to absorb visible light in the sunlight to form photoelectrons and generate electrical current. Photo-thermal power generation utilizes a medium such as molten salt or oil to absorb heat energy in the sunlight and converts it into electricity using a steam turbine.

2. It is difficult to connect different grids.

At present, solar thermal power generation systems can improve output characteristics by adding thermal storage units or by supplemental combustion or combined with conventional thermal power generation, with stable output power and adjustable power. Photovoltaic power generation is greatly affected by the intensity of sunlight, and it brings great pressure on the power grid after the Internet access. Its unique form of power generation is difficult to merge with traditional power plants. In terms of the degree of difficulty in grid connection, CSP has more advantages than conventional photovoltaic power generation. Improve the output characteristics of photo-thermal power generation through the heat storage (tank type and tower type photo-thermal power generation). During the day, excess heat is stored, and then stored heat is used to release electricity at night. In this way, continuous power supply by CSP can be realized, current stability can be ensured, and grid-connected peak shaving problem that photovoltaic generation and wind power are difficult to solve can be avoided. According to different heat storage modes, the utilization hours and power generation capacity of the power station can be increased to a certain extent, and the adjustment performance of the power station can be improved.

Photovoltaic power output characteristics are improved through supplemental combustion or combined operation with conventional thermal power. Solar thermal power stations can use fossil fuels to supplement or operate in conjunction with conventional thermal power generation, so that they can continue to generate electricity at night or during continuous cloudy days. They can even operate with a steady output base load, so that the annual power generation can reach 7,000 hours.

3, the degree of pollution of the environment.

Photovoltaic power generation is a clean production process. Basically, physical means are used for photoelectric energy conversion. The harm to the environment is minimal, and the CO2 emission of the solar thermal power station is only 13-19 g/kWh over its entire life cycle. Photovoltaic power generation technology has a fatal weakness. The loss of the solar battery to the environment during the production process is large, and it is a production process with high energy consumption and high pollution.

4, the different levels of technology maturity.

The conventional photovoltaic power generation technology has developed steadily in our country, and the technology is relatively mature. However, the solar thermal power generation has risen in foreign countries very early. However, in China, it is still in the stage of continuous technological innovation and improvement.

China's CSP industry has entered a period of rapid development after experiencing an upsurge of development in previous years. The “Thirteenth Five-Year Plan” will become the key five-year period for China’s CSP industry to break, and it will In the five years, another big market of 100 billion yuan will be presented.