Main content:
In China's vast and rich land, there are very rich solar energy resources. The total radiation of solar energy resources across the country is 334~8400MJ/(m2·a), with a median value of 5852MJ/(m2·a). From the distribution of total annual solar radiation in China, Tibet, Qinghai, Xinjiang, southern Inner Mongolia, Shanxi, northern Shaanxi, Hebei, Shandong, Liaoning, western Jilin, central and southwestern Yunnan, southeastern Guangdong, southeastern Fujian. The total radiation of solar energy resources in vast areas such as eastern and western Hainan Island and southwestern Taiwan is very large. Especially the Qinghai-Tibet Plateau is the largest, where the average altitude is above 4000m, the atmosphere is thin and clean, the transparency is good, the latitude is low, and the sunshine time is long.
1. The main characteristics of the distribution of solar energy resources in China
Both the high-value center and the low-value center of solar energy resources are located in the area of latitude 22°~35°N, among which the Qinghai-Tibet Plateau is the high-value center of solar energy resources, and the Sichuan Basin is the low-value center of solar energy resources; the total annual radiation of solar energy resources, The western region is higher than the eastern region, and except for the two autonomous regions of Tibet and Xinjiang, the southern region is basically lower than the northern region; due to the cloudy and rainy majority of the southern regions, in the 30°~40° north latitude region, the distribution of solar energy is similar to that in the north. The general law of solar energy changing with latitude is opposite, the solar energy resources do not decrease with the increase of latitude, but increases with the increase of latitude.
In order to make better use of solar energy resources according to different conditions in different places, the country can be divided into the following five types of regions according to the total amount of solar radiation received by each region:
Class I area: the annual sunshine hours are 3200~3300h, and the total amount of solar radiation received per square meter in one year is 6680~8400MJ, which is equivalent to the heat emitted by the combustion of 225~285kg of standard coal. This region mainly includes northern Ningxia, northern Gansu, southern Xinjiang, western Qinghai, and western Tibet. It is the region with the most abundant solar energy resources in China, comparable to the solar energy resources in northern India and Pakistan. In particular, the Tibet Autonomous Region has the most abundant solar energy resources, with the highest total radiation amount of solar energy resources reaching 8400M/m2, second only to the Sahara Desert and ranking second in the world.
The second-class area: the annual sunshine is 3000~3200h, and the total solar radiation received per square meter area in one year is 5852~6680MJ, which is equivalent to the heat emitted by the combustion of 200~225kg of standard coal. This area mainly includes northwestern Hebei, northern Shanxi, southern Inner Mongolia, southern Ningxia, central Gansu, eastern Qinghai, southeastern Tibet and southern Xinjiang, and is an area rich in solar energy resources in China.
Three types of areas: The annual sunshine hours are 2200~3000h, and the total amount of solar radiation received per square meter in one year is 5016~5852MJ, which is equivalent to the heat emitted by the combustion of 170~200kg of standard coal. This area mainly includes Shandong, Henan, southeastern Hebei, southern Shanxi, northern Xinjiang, Jilin, Liaoning, Yunnan, northern Shaanxi, southeastern Gansu, southern Guangdong, southern Fujian, northern Jiangsu, northern Anhui, and southwestern Taiwan. It is a medium type area of solar energy resources in China.
Four types of areas: The annual sunshine hours are 1400~2200h, and the total amount of solar radiation received per square meter in one year is 4190~5016M, which is equivalent to the heat emitted by the combustion of 140~170kg of standard coal. This area mainly includes Hunan, Hubei, Guangxi, Jiangxi, Zhejiang, northern Fujian, northern Guangdong, southern Shaanxi, southern Jiangsu, southern Anhui, Heilongjiang, and northeastern Taiwan. It is an area with relatively poor solar energy resources in China.
Five types of areas: the annual sunshine hours are 1000-1400h, and the total amount of solar radiation received per square meter in one year is 3344-4190M, which is equivalent to the heat emitted by the combustion of 115-140kg of standard coal. This region mainly includes Sichuan and Guizhou provinces. This is the region with the least solar energy resources in China.
The first, second and third types of regions are the regions with abundant or relatively abundant solar energy resources in China. These three types of areas are large, accounting for more than 2/3 of the country's total area, and have good conditions for utilizing solar energy resources. In the fourth and fifth types of areas, although the conditions of solar energy resources are poor, they also have certain utilization value, and some places may develop and utilize solar energy resources. In short, from a national perspective, China is a country rich in solar energy resources, and has unique advantages to develop solar energy resource utilization. The solar energy resource utilization business in China has broad prospects for development. Compared with other countries at the same latitude, China's solar energy resources are quite rich in solar energy resources in most regions except the Sichuan Basin and its adjacent areas. Similar to the United States, it is much better than Japan and Europe, especially the Qinghai-Tibet Plateau. The central and southern regions are particularly rich in solar energy resources, close to the world's most famous Sahara desert.
Due to the high altitude, clean weather, dry air and low latitude in the Tibetan Plateau, the total radiation of solar energy resources is large. The annual total radiation of solar energy resources in Tibet is mostly between 6,000 and 8,000 MJ/m2, with an increasing distribution from east to west. In the southeastern edge of Tibet, there are more clouds and rain, and the total annual radiation of solar energy resources is less than 5155MJ/m2; in the valleys of the middle reaches of the Brahmaputra River, there is less rain, and it rains at night, and the total annual radiation of solar energy resources reaches 6500~8000MJ/m2. At the Rongbu Monastery at an altitude of 5000m on the north slope of Mount Everest, the annual average total radiation of solar energy resources observed from April 1954 to March 1960 was as high as 8369.4 MJ/m2. Even in Qamdo, where the total radiation of solar energy resources is relatively small, its annual total radiation is greater than that of all the inland regions, and is comparable to that of central Inner Mongolia. Compared with the total annual solar radiation of all countries in the world, the Tibetan Plateau is also one of the areas with abundant sunshine.
The annual variation curve of the total radiation of solar energy resources is peak-shaped. The monthly total radiation is generally the largest in May, and the monthly total radiation is above 500MJ/m2. The middle and upper reaches of the Brahmaputra, Qiangtang and Ali Plateau can reach more than 700MJ/m2. Shiquan River is 853.4MJ/m2, Rongbu Temple once reached 933.7MJ/m2. The lowest value generally appears in December, and the monthly total radiation is between 318.5 and 510.9 MJ/m2. The seasonal variation of total solar radiation of solar energy resources is the largest in spring and summer, and the smallest in autumn and winter. The total radiation of solar energy resources in the rainy season accounts for about 46% to 49% of the whole year.
The Tibetan Plateau is one of the high-value centers of sunshine hours in China, with an annual average sunshine hours between 1500 and 3400 hours. Its regional distribution is characterized by the largest number in the west, where the annual sunshine hours of Shiquan River are 3417h, followed by Dingri on the north slope of Mount Everest, with 3327h annual sunshine hours. The annual average sunshine hours decrease in turn toward the southeast, and Bomi is only 1544h.
The distribution law of the annual average number of days with daily sunshine hours ≥6h is basically the same as that of sunshine hours. Shiquan River is the largest, reaching 330d, Dingri is 327d, and Zayu is the least, only 127d.
The annual variation of sunshine hours is basically divided into two types. The first type is the double-peaked type, which is the case in most areas of Tibet, with the middle and upper part of the Brahmaputra Valley and its south area being the most typical. The second type is a three-peak type, which mainly occurs in the rainy areas of southeastern Tibet.
2. Specific comments on solar energy resources in Tibet
2.1 Solar Energy Resources Area in Western Tibet
This area is located in the western part of Tibet, mainly including the Ngari area, the western part of Nagqu, the western part of the middle and upper reaches of the Yarlung Zangbo River, and the Jiangnan area. The annual sunshine hours in the area are 2900~3400h, the total annual radiation of solar energy resources is as high as 7000~8400MJ/m2, the annual average number of days with daily sunshine hours ≥6h is between 275~330d, and the daily sunshine hours in each month are ≥6h In terms of the average number of days, the lowest value appeared in February in the Ali area and Nyalam station, between 19-24d, and other stations appeared in July-August, generally 17-22d. Except Langkazi's use of solar energy resources is slightly poor in August, all other stations can use solar energy resources throughout the year, which is a class I area of solar energy resources in Tibet.
2.2 The southern wing of the Himalayas—the central and eastern part of Nagqu—Chamdo Solar Energy Resources Area
This area includes Yadong, the southern part of Luoza and Tsomei counties, Cuona, Jiacha, the western part of Lang County, Gongbu Jiangda, Jiali, Nagqu, Amdo, Nierong, Suo County, Baqing, Bianba, Dingqing , Luolong, Leiwuqi, Basu, Jiangda, Qamdo, Gongjue, Pali, Chaya, Mangkang and other counties. The total radiation of solar energy resources in the area is 6250~7000MJ/(m2·a), the total number of days in the year is 2250~299h, and the average number of days with sunshine hours ≥6h per day in the year is between 215~275d
In terms of the utilization time of solar energy resources, the distribution in this area is uneven. The average monthly number of days with daily sunshine hours ≥ 6 in Luolong, Amdo, Nagqu, Dingqing, Ludu and Jiacha is more than 15d. use. Suo County in July, Mangkang in August, Jiali in July and August, Cuona in July and August, Leiwuqi in June, July and September, and Yadong and Pali in June and September are all below 15d. The solar energy resources can be used, and it is a Class II area of solar energy resources in Tibet.
2.3 Solar Energy Resources Area in Southeast Tibet
This area mainly refers to the part of the southern wing of the Himalayas, the eastern part of Lang County, Nyingchi, Rui, Bomi, Yigong and Zuogong. It is 2000-2250h, and the average number of days with sunshine hours ≥ 6h per day in the whole year is between 150 and 215d. The best utilization period is generally from June to September. Zuogong from October to June of the next year is the best utilization period; Linzhi’s utilization period is only 5 months, that is, October to January and April of the following year; for example, it is intermittently distributed, April to June, August, October The best use period is the month of the next year, and other months cannot be used. This area is a Class III area of solar energy resources in Tibet.
2.4 Solar energy resources area in the lower reaches of the Brahmaputra
This area mainly refers to the lower reaches of the Brahmaputra, including the southern part of Milinbomi, Medog, and Zayu. The annual sunshine hours in the area are less than 2000h, and the BOM is only 1544h; the annual total radiation of solar energy resources is below 5850M/m, and the BOM is only 5116M/m2; During the period, the monthly average number of days with daily sunshine hours ≥6h is less than 15d in other months except for individual months. This area is a Class IV area of solar energy resources in Tibet.
Read more: Factors Affecting Solar Radiation Energy Reaching the Earth's Surface