Solar-Coal Hybrid Thermal Power Generation —an Efficient Way to Use Solar Energy in China

Hongjuan Hou; Jian Mao; Na Luo; Yongping Yang
To solve the problem of high initial investment and low thermal performance for solar alone thermal power plant, solar/fossil fuels hybrid power system has become a trend of solar thermal power generation in recent years. China is rich in coal and solar energy. At present, coal is the main resource in generating electricity in China. Therefore, solar integrated with conventional coal-fired power generation cycles is considered the best way in China. As an option for easy operation and control flexibility, solar aided feedwater heating of a coal-fired power generation system is discussed and analyzed in this paper. Compared to the common hybrid power system, the main feature of this generation system is, the thermal oil carrying solar energy replaces the extraction steam to heat the feed water and the steam thus saved can continue to do work. Because the solar heat does not enter the turbine, the efficiency (of solar to power) is not limited by the temperature of the solar heat. The performance of the integrated system with different replacements is analyzed based on an example and the impact of solar collector areas and DNI (direct normal irradiation) on the performance of the generation system is discussed as well. The results show that the new integrated system not only contributes to increasing the efficiency of the conventional power station and reducing its emission of greenhouse gases, but also increases the efficiency of solar to electricity; further LEC is also reduced considerably compared with solar only thermal power system. However, the results also indicate that the replacement type, solar collector areas and DNI have great influence on the generation system.
Solar Energy; Coal-Fired Thermal Power Generation; Hybrid; Performance
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