風(fēng)力發(fā)電機(jī)畢業(yè)論文英文文獻(xiàn)翻譯(編輯修改稿)
2024-10-08 08:56 本頁面
【文章內(nèi)容簡介】 機(jī)畢業(yè)論文英文文獻(xiàn)翻譯 (Reproduced by permission of Wind Prospect Ltd) and the potential of wind energy to help limit climate change. In 1997 the Commission of the European Union published its White Paper (CEU, 1997) calling for 12 percent of the gross energy demand of the European Union to be contributed from renewables by 2020. Wind energy was identified as having a key role to play in the supply of renewable energy with an increase in installed wind turbine capacity from GW in 1995 to 40 GW by 2020. This target is likely to be achievable since at the time of writing, January 2020, there was some 12 GW of installed windturbine capacity in Europe, GW of which was constructed in 2020 pared with only 300 MW in 1993. The average annual growth rate of the installation of wind turbines in Europe from 19939 was approximately 40 percent (Zervos, 2020). The distribution of windturbine capacity is interesting with, in 2020, Germany account ing for some 45 percent of the European total, and Denmark and Spain each having approximately 18 percent. There is some GW of capacity installed in the USA of which 65 percent is in California although with increasing interest in Texas and some states of the midwest. Many of the California wind farms were originally 風(fēng)力發(fā)電機(jī)畢業(yè)論文英文文獻(xiàn)翻譯 constructed in the 1980s and are now being reequipped with larger modern wind turbines. Table shows the installed windpower capacity worldwide in January 2020 although it is obvious that with such a rapid growth in some countries data of this kind bee out of date very quickly. The reasons development of wind energy in some countries is flourishing while in others it is not fulfilling the potential that might be anticipated from a simple consideration of the wind resource, are plex. Important factors include the financialsupport mechanisms for windgenerated electricity, the process by which the local planning authorities give permission for the construction of wind farms,and the perception of the general population particularly with respect to visual impact. In order to overe the concerns of the rural population over the environmental impact of wind farms there is now increasing interest in the development of sites offshore. Modern Wind Turbines The power output, P, from a wind turbine is liven by the wellknown expression: P= where ρ is the density of air ( kg/ ), is the power coefficient, A is the rotor swept area, and U is the wind speed. The density of air is rather low, 800 times less than that of water which powers hydro plant, and this leads directly to the large size of a wind turbine. Depending on 風(fēng)力發(fā)電機(jī)畢業(yè)論文英文文獻(xiàn)翻譯 the design wind speed chosen, a MW wind turbine may have a rotor that is more than 60 m in diameter. The power coefficient describes that fraction of the power in the wind that may be converted by the turbine into mechanical work. It has a theoretical maximum value of (the Betz limit) and rather lower peak values are achieved in practice (see Chapter 3). The power coefficient of a rotor varies with the tip speed ratio (the ratio of rotor tip speed to free wind speed) and is only a maximum for a uni
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