文章基本信息

标题：Wind speed reductions by large-scale wind turbine deployments lower turbine efficiencies and set low generation limits
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作者：Lee M. Miller ; Axel Kleidon
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2016
卷号：113
期号：48
页码：13570-13575
DOI：10.1073/pnas.1602253113
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceUnderstanding the limits of electricity generation from winds is a requirement for planning a renewable energy future. A difficulty in estimating such limits is that wind turbines remove kinetic energy from the atmosphere, so that many turbines should reduce wind speeds, ultimately setting a limit to how much kinetic energy can be taken out of the atmosphere. We show that this slowdown effect can be accounted for by detailed climate model simulations and a relatively simple method that does not directly simulate atmospheric dynamics. This slowdown effect is critical to consider, as it makes each turbine less productive and shows that few land areas can yield more than 1.0 We m-2 of electricity at large scales. Wind turbines generate electricity by removing kinetic energy from the atmosphere. Large numbers of wind turbines are likely to reduce wind speeds, which lowers estimates of electricity generation from what would be presumed from unaffected conditions. Here, we test how well wind power limits that account for this effect can be estimated without explicitly simulating atmospheric dynamics. We first use simulations with an atmospheric general circulation model (GCM) that explicitly simulates the effects of wind turbines to derive wind power limits (GCM estimate), and compare them to a simple approach derived from the climatological conditions without turbines [vertical kinetic energy (VKE) estimate]. On land, we find strong agreement between the VKE and GCM estimates with respect to electricity generation rates (0.32 and 0.37 We m-2) and wind speed reductions by 42 and 44%. Over ocean, the GCM estimate is about twice the VKE estimate (0.59 and 0.29 We m-2) and yet with comparable wind speed reductions (50 and 42%). We then show that this bias can be corrected by modifying the downward momentum flux to the surface. Thus, large-scale limits to wind power use can be derived from climatological conditions without explicitly simulating atmospheric dynamics. Consistent with the GCM simulations, the approach estimates that only comparatively few land areas are suitable to generate more than 1 We m-2 of electricity and that larger deployment scales are likely to reduce the expected electricity generation rate of each turbine. We conclude that these atmospheric effects are relevant for planning the future expansion of wind power.
关键词：momentum ; natural limits ; surface stress ; wind energy ; vertical transport