Wind Energy Resource Characteristics and Development Potential
Since the late 1980s there have been several studies to assess China’s wind resource potential with widely varying results. The third national wind energy resource survey conducted by the China Meteorological Administration (CMA) is among the most commonly cited studies. Based on historical data collected from 1971 to 2000 at more than 2000 weather stations across the country, wind resources at a height of 10 meters were assessed. These assessments identified technically exploitable on-shore wind resources representing a power generation capacity of 250 GW or 300 GW respectively, and an off-shore potential of around 750 GW.
In a study conducted by the National Renewable Energy Laboratory (NREL) as part of the Solar and Wind Energy Resource Assessment (SWERA) project for the United Nations Environment Programme (UNEP), the exploitable resource potential at 50m is estimated at 3250 GW on land and 800 GW off-shore. The Center for Wind and Solar Energy Assessment estimates the technically exploitable potential on-shore at 2680 GW and the off-shore potential at 180 GW.
It is important to note that the studies mentioned, for the most part do not represent the actual, economically exploitable wind resource potential; i.e. land-use exclusions, the existing transmission grid and accessibility with regard to infrastructure are not taken into consideration. Considering these factors only around 30% of the potential may be available for wind power projects. The variation of results is largely due to differences in the methodologies used for resource assessment. Different assumptions with respect to the height at which resources where assessed, the threshold above which wind power intensity is deemed to be exploitable and the density at which wind turbines may be installed are further explanations for the widely differing results. The height at which wind resources are assessed is of crucial importance: compared to 10m, at 50m the wind resource potential is usually twice as much, at 70m resource potential is increasing by another 10%.
Wind resource assessment studies conducted to date lack accuracy and do not satisfy the requirements for proper identification of wind farm sites. Hence, inaccurate resource assessment poses a major impediment to the formulation of detailed provincial wind power development plans. In addition, lack of reliable wind resource data negatively impacts the risk profile, restricting access to loans and proper insurance of wind power projects.
Currently, CMA is in the process of preparing a new, more detailed nation-wide wind resource survey to address the problem of inaccurate resource assessment. More than 400 specially designed masts of 70m, 100m and 120m height are to be erected in China’s wind resource rich areas. The survey, which is supposed to be completed by 2011, will combine wind resource observation data, data modelling methods and comprehensive evaluation in order to develop a detailed wind resource map serving as a sound basis for future wind power development. Furthermore, the EU-China Energy and Environment Programme is currently conducting an assessment of the offshore wind energy resources along the coastline of Fujian to Shandong province.
Despite the absence of good data today, there is agreement that China is bestowed with rich wind resources allowing for the development of wind power on a large scale. The most commonly cited estimate on economically exploitable potential for wind power development in China, including both on- and offshore installations, amounts to 1.000 GW. The total installed capacity in 2009 of around 23 GW represents only a tiny fraction of the total wind resource potential, leaving the vast amount of resource potential untapped and open for large scale wind power development.
Distribution of Wind Power Density in China
Source: BCSE/CREIA (2006), p. 33
The areas with the richest wind energy resources are located in the north of China as well as the south-eastern coastal areas and its adjacent islands (see Figure 9). In addition, there are several wind-rich areas inland as well as off-shore. In northern China, a 200 km-wide belt rich in wind energy spans from the north-eastern provinces of Liaoning, Jilin and Heilongjiang, via Inner Mongolia, Gansu and Ningxia to Xinjiang in the northwest. Wind power intensity in these areas is usually between 200 and 300 W/m² with wind power intensities reaching a maximum of 500 W/m² in the areas with the strongest wind in Xinjiang and Inner Mongolia.
The most abundant wind energy resources along the coastline and near-coast islands are located within a 10 km-wide belt including the provinces of Shandong, Zhejiang, Fujian, Guangdong, Guangxi and Hainan with an annual wind power intensity above 200 W/m². Except for some areas where wind resource potential is influenced by special geographic characteristics like lakes, in most inland regions outside the two areas mentioned above the wind power intensity is generally below 100W/m². Furthermore, vast areas with potential for off-shore wind power development can be found along the eastern coastal areas at easily accessible water depths ranging from 5 to 20 metres. These resources are mainly located in the provinces of Jiangsu, Fujian, Shandong and Guangdong.
Seasonal Characteristics and Distance to Load Centers
In their seasonal variation China’s wind and hydro resources complement each other. The high-season for hydro-power generation is in summer. Especially in south China, winters are dry and flooding season in summer accounts for most of the annual rainfall. Wind on the other hand is generally strong during spring, autumn and winter, while being scarce in summer. Therefore, wind power can help compensate for the lack of electricity generation from hydro-power during dry season in spring and winter.
Imbalance of Power Production and Consumption in China
Source: IEA (2007), p. 267
The geographical distribution of wind energy resource does not match the country’s power load profile however. The heavy power loads are concentrated in the economic centres along eastern coastal provinces, where inland wind resources are scarce. Consequently, wind power development is amplifying the present imbalance of power production and consumption. While in the northern regions, where wind resources are abundant, the power loads are small and the grid infrastructure is weak. The large distance between wind-rich areas and power load centres makes heavy investment into grid reinforcement necessary, in order to support large-scale wind power development. In future, as off-shore technology matures and becomes economically viable the deployment of wind farms on sea close to the load centres may help alleviate the problem of geographical dispersion of wind resources. The large-scale exploitation of offshore wind resources is not expected for the near future though, because of the rich inland resources and the technical challenges of offshore wind farm construction and operation.