Evaluation Analysis On Solar Energy Resources In Ningxia

With the rapid development of society, human demand for energy is growing. The solar energy is a clean, safe, renewable new energy resource. Our country is rich in solar energy resource, and the potential of exploitation and utilization is very great. Based on the long series observation data, the distribution characteristic of the radiation and the sunshine for different time scale is revealed in Ningxia province. From rich degree, utilization value, stability degree, the optimal using period and other aspects, the comprehensive analysis on potentiality of the solar energy resource is carried on, so to provide scientific basis for the rational development and utilization of solar energy resources in Ningxia province.The sunshine data used in this paper is 30a standard climate data from 1971 to 2000 for all the observation stations. The radiation material is each month measured total radiation for Yinchuan station (38°29'N,106°13'E) from 1961 to 2004 and Guanyuan station (36°00'N,106°16'E) from 1984 to 2004.There are many solar radiation calculation methods, the most widespread method is a climatologic calculation model that using percentage of sunshine and solar radiation to establish a linear regression equation. The relative error between calculated total solar radiation from the climatologic model and measured is small, so the model can satisfy the general application. But how to use the model to calculate more precise solar radiation value for Yinchuan and Guyuan station in Ningxia province, it is a content which is worth studying.Through the climatologic computation model, the local coefficient as and bs of solar radiation flux model for Yinchuan and Guyuan area is retrieved. But in order to obtain a set of optimal coefficients, a new method is introduced, firstly, preliminary screening test is carried on with assigning as and bs certain threshold value separately, and then different value test of two sample year is carried on in order to determine the optimal coefficient. As a result, local coefficient of solar radiation flux model is and 0.62 for as and bs separately for Yinchuan,0.16 and 0.58 for as and bs separately for Guyuan. Using the average deviation(MBE), the mean absolute deviation(MABE), the root mean square deviation(RMSE), the mean absolute error(MAPE) and other methods, history yearly simulation results is examined, and has a high credibility degree. The variation of the monthly and yearly simulated solar radiation and the monthly and yearly measured solar radiation for Yinchuan and Guyuan station is analyzed. The result shows that the annual variation of monthly solar radiation has a weakly decreased tendency in Yinchuan, and the annual variation of solar radiation for the period of March to June has increased tendency, while it has a weak tendency to reduce for other months in Guyuan. In Yinchuan, yearly solar radiation tends to decrease, and simulated value is lager than measured value. Yearly solar radiation shows an increasing trend, and the variability of simulated result is slightly few than the variability of measured. The yearly solar radiation of other station in the region is calculated, as a result, the variation of yearly solar radiation flux of the 30 years performs three different trends:increasing tendency, steady, decreased tendency. The stations with decreasing tendency are Taole, Yinchuan, Weizhou, Tongxin and Haiyuan, the stations with steady tendency are Yongning and Xiji, and the stations with increasing tendency are Pingluo, Helan, Lingwu, Wuzhong, Qingtongxia, Zhongwei, Xingren, Yanchi, Guyuan, Longde and Jingyuan.Based on this, solar energy resource division is carried on in Ningxia province, the result shows that solar energy resource vary from region to region, on the whole, the energy resource is larger in north than in south, north-south difference is more than 1000MJ/M2 a year. The region with high and well-distributed solar energy resource between 5864-6100 MJ/M2 a year is located in Huanghe river irrigated area and Yanchi and Tongxin region in central dry zone, this region is solar energy rich area in Ningxia, and is also one of high solar radiation regions in our country. In addition, the direct solar radiation, scattered radiation, photosynthetically active radiation,45°slope solar radiation, sunshine time distribution and more than 6 hour sunshine hours are calculated, and the distribution of the number of the day with 5% above total could cover is analyzed, which offer data support for the solar energy resource assessment analysis.Saving energy is took as a basic national policy in our country, energy saving and emission reduction is energetically advocated, and renewable energy is developed. The results of this study has a widespread application prospect for the utilization of solar energy in Ningxia province.