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| Fig. 1: The increase of cumulative installed wind power capacity in China. (Data from [1].) |
As the energy demand of China is increasing almost 10% every year, the Chinese government pays a lot of attention to renewable energies. Wind energy appears to be one of their major choices. In order to understand the situation of wind energy in China, several critical pieces of information are introduced here.
Chinese government is pushing the whole wind industry very hard into a fast track, as can be seen in Fig. 1. Since 2005, the total installed capacity of China doubles every year. With 7.8 GW installations in the first six months of this year (2010), there is a total of 34 GW installation of wind power in China. [1] Holding the 10th world-ranking of total installed capacity in 2005, China has quickly climbed up to the 2nd as for 2009, and will very likely exceed the US by the end of 2010, to be the largest wind power country of the world.
When calculating the actual output power, we have to include the capacity factor. Capacity factor indicates the actual operating time of a wind turbine. This number depends on local wind speed distribution (which dictates whether or not turbine can run up to its full capacity), vintage of turbines, and the down time needed for maintenance. In China, most wind farms claim an annual capacity factor of around 23%, a little bit lower than other countries (e.g. in the US 48% for recently deployed and an average of ~35%). [2,3] The estimated actual output power from wind energy for year 2010 will be 7.8 GW, which can contribute to 1.8% of the total net electricity generation of China as the year of 2009. [4,5]
Lands are very precious in China given its huge population. Hence it is important to compare the power generation per unit area (or capacity density) between wind power and solar power, which is another important renewable energy.
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| Fig. 2: Wind power distribution in China. Source: Chinese Meteorological Administration. |
The metric of land use for wind power plants remains ambiguous. Although a wind power plant may cover a large area, the turbines alone do not occupy a lot of area, and the land between the turbines can still be well used, like for farming and stock raising. So there exist two major indices of land use: the total area and direct impact area. The former one refers to the overall area of a wind power plant and the later refers to the land directly disturbed by the turbines. For wind power plants in the US, the average capacity density of wind power plants is 3.0 MW/km2 (taking the total area for calculation) and 333 MW/km2 (taking the direct impact area for calculation), respectively. [6] In comparison, a solar panel produces about 110 MW/km2 on average, which is about one third of the capacity density of wind farm using the direct impact area index. [7] While building a solar power plant, maximally 40% of the total plant land use can be installed with solar panels. Thus a solar power plant can have a capacity density of 44 MW/km2 in terms of total area use, which is roughly 10-fold higher than the total-area capacity density of wind power plant. However, as mentioned earlier, most of land in a wind power plant can be used for other things, which is not true for a solar power plant. Consequently, the capacity density of a wind power plant is at least comparable with that of a solar power plant, if not higher.
Wind energy distribution is not even in China. As we can see from Fig 2, in general northern and western China has a lot more wind resource than the rest area. Therefore, most wind farms are located accordingly. One third of the total capacity is installed at Inner Mongolia, over 70% of the total capacity is located in the northern and western provinces (Xinjiang, Ningxia, Inner Mongolia, Liaoning, Jilin, Heilongjiang). [8]
China is now the world's fastest growing market for wind energy. To meet the fast economy growth and great demand of electricity, clean and renewable energy like wind are expected to play a much more important role in the near future.
© Xi Jin. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "Global Wind Report 2009," Global Wind Energy Council.
[2] D. Cyranoski, "Beijing's Windy Bet," Nature, 457, 372 (2009).
[3] M. B. McElroy et al., "Potential for Wind-generated Electricity in China," Science 325, 1378 (2009).
[4] National Bureau of Statistics of China.
[5] China," CIA World Factbook.
[6] P. Denholm et al., "Land-Use Requirements of Modern Wind Power Plants in the United States," National Renewable Energy Laboratory, Technical Report, NREL/TP-6A2-45834, August 2009.
[7] T. J. Dijkman and R. M. J. Benders, "Comparison of Renewable Fuels Based On Their Land Use Using Energy Densities," Renewable and Sustainable Energy Reviews 14, 3148 (2010).
[8] J. Li, P. Shi and H. Gao, "China Wind Power Outlook 2010," Global World Energy Council, October 2010.