Generic System Requirements for High Altitude （通用系统要求高海拔）.pdfVIP

Generic System Requirements for High Altitude Wind Turbines Nykolai Bilaniuk, Ph.D., P.Eng. CEO, LTA Windpower Ottawa, Canada v1 - October 2009 ABSTRACT The basic concept of a high altitude wind turbine (or still more generally, airborne tethered wind generator) appears to have merit based on the fact that abundant energy is present in the wind at heights beyond the reach of current wind turbine towers. However, exploiting that energy is a challenge. Many different technologies in this vein have been proposed but they cant all be equally promising. This paper is intended to assist the prospective investor or purchaser in reasoning through this technology area: it explores the practical requirements that must be met by an airborne tethered wind generator technology to be both technologically feasible and economically viable. The paper concludes that autonomous survivability is a largely neglected but critical aspect of performance. Introduction Wind power is not usually viable as a sole source of electricity because it is difficult to match supply and demand. However, it can be an attractive supplement to other forms of electrical generation. This includes on-grid use, where windpower isnt economically competitive with fossil fuels or hydro, but brings ecological benefits that governments use to justify subsidies. Wind power makes even more sense in off-grid applications displacing fuel that would otherwise have been consumed by diesel generators. By way of introduction, it would be useful to define a few windpower related terms, particularly for a non-specialist audience. Some other terminology may be introduced later. - Efficiency is the fraction of the energy in the wind in the area intercepted by the wind system that is usefully captured for conversion to electricity at a given instant. Theory proves that the upper bound on possible efficiency is 16/27ths or slightly over 59%, called the Betz Limit. The symbo