Assessment of Solar Energy Resource and Its Exploitation Potential in South China

Based on the exposure radiation data and sunshine hourly data of 156 standard meteorological observatories in south China during 1981-2010, temporal and spatial distribution of solar energy resource in south China is evaluated. Results show that the annual irradiation on optimal inclined plane is 1291 kW·h·m^-2, 3% higher than that on the horizontal plane. The distribution of solar energy in Guangxi and Guangdong increases as the latitude decreases, whereas it appears as high in the west and low in the east of Hainan. The stability of solar energy resource in most area of south China is at stable level except the eastern Guangxi and the northwest corner of Guangdong. Hainan's solar energy resource stability is the highest: Larger than 2/3 of its area is at very stable level and only a few parts of eastern Hainan is at stable level. Combined with terrain data and land cover data, the exploitation suitability and potential usability of solar energy resource in south China are divided and analyzed with the resolution of 90 m×90 m and 1 km×1 km. Under the resolution of 90 m×90 m, solar energy exploitation suitability zoning results show that the area of class Ⅰ, Ⅱ and Ⅲ account for more than 80% of the total area in south China (occupying 22.1%, 32.4%, 26.7%, respectively), and their proportions of solar energy are slightly higher than their proportions of area. Solar energy exploitation potential results show that bare land and shrub-grass area accounts for only 13.9% of the total area in Ⅰ, Ⅱ and Ⅲ classes. While cultivated land (34.8%) and forest land (29.2%) are the largest two land cover types in these three usable regions. In the actual exploitation and application project, besides to give priority to using bare land and shrub-grass area, cultivated land and forest land should not be abandoned directly. Under the principle of no changing land use properties of cultivated land and forest land and no sacrificing the vegetation coverage, solar energy resource should be rationally exploited in these areas. Suitability zoning results derived from data with 1 km×1 km resolution are not the same with that using data with 90 m×90 m resolution, then make statistical results of exploitation potential different. Results mainly affected by the difference of the resolution of terrain data and the acquisition time of land cover data. While making solar energy development plan, reasonable data should be chosen according to the size of actual project.