Airborne wind energy: Optimal locations and variability

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Unlike wind turbines mounted on towers, AWE systems can be automatically raised and lowered to the height of maximum wind speeds, thereby providing a more temporally consistent power production. Most locations on Earth have significant power production potential above the height of conventional turbines. The ideal candidates for AWE farms, however, are where temporally consistent and high wind speeds are found at the lowest possible altitudes, to minimize the drag induced by the tether. A criterion is introduced to identify and characterize regions with wind speeds in excess of 10 m s À1 occurring at least 15% of the time in each month for heights below 3000 m AGL. These features exhibit a jet-like profile with remarkable temporal constancy in many locations and are termed here "wind speed maxima" to distinguish them from diurnally varying low-level jets. Their properties are investigated using global, 40 km-resolution, hourly reanalyses from the National Center for Atmospheric Research's Climate Four Dimensional Data Assimilation, performed over the 1985e2005 period. These wind speed maxima are more ubiquitous than previously thought and can have extraordinarily high wind power densities (up to 15,000 W m À2 ). Three notable examples are the U.S. Great Plains, the oceanic regions near the descending branches of the Hadley cells, and the Somali jet offshore of the horn of Africa. If an intermediate number of AWE systems per unit of land area could be deployed at all locations exhibiting wind speed maxima, without accounting for possible climatic feedbacks or landuse conflicts, then several terawatts of electric power (1 TW ¼ 10 12 W) could be generated, more than enough to provide electricity to all of humanity.

Airborne wind energy resource analysis

“…They further state that uniformly distributed wind turbines generating the entire global primary power demand of 18 TW are unlikely to substantially affect the climate. Archer et al [22] explore the global wind power potential by accounting for the specific operational characteristics of AWE systems. Although they allow a variable harvesting height, they also conclude that the optimal locations are where temporally consistent and high wind speeds occur at lowest possible altitudes, to minimize the drag losses of the tether.…”

The Orinoco Low‐Level Jet: An Investigation of Its Characteristics and Evolution Using the WRF Model

“…LLJs have been the focus of many prior investigations owing to the diversity of their impacts. These include wind energy generation (Archer et al, ; Storm et al, ), fire weather (Fromm & Servranckx, ; Petroliagkis et al, ), transport of hazardous airborne substances (Banta et al, ; Darby et al, ), air quality (Banta et al, , ), bird migration (Liechti & Schaller, ), and aviation (Balmez & Ştefan, ; Blackadar, ; International Civil Aviation Organization, ).…”

Design of an airborne vertical axis wind turbine for low electrical power demands

“…Less attention has been paid to high-altitude wind, which is less influenced by these factors, leading to steadier, more persistent, and higher velocity wind energy. Generally, wind energy increases with altitude, leading to the idea of an altitude wind energy system [6][7][8][9].…”