As if the need for safe and renewable energy weren't already poignant enough, the recent disasters in the Gulf of Mexico and Japan have raised the issue to the top of our collective newswire consciousness.
I just drove through a massive wind farm in Western Indiana, where thousands of huge, white, propeller-style windmills tessellated the flat landscape as far as the eye could see. Underneath, hardly-disturbed farmland was being plowed for a new growing season, and "oversized load" convoys brought in a procession of gargantuan post segments, blades, and generators ready to be installed.
This vision represents significant progress on a variety of levels -- social, economic, geopolitical, and environmental. However, someday soon these beautiful spinning machines may look as outdated to us as their ancestors in the Old West and in Old Europe.
Windmills need wind with a laminar or sheet-like flow across a landscape. One property of such wind is that its speed varies with distance from the underlying terrain, because the terrain acts as a source of friction. As a result, the higher a windmill is, the more energy it can harvest.
A brilliant and very recent idea is to put the windmill much higher into the atmosphere, and to control where it goes. What better idea than a kite? Kite-style windmills have been proposed that use a buoyant blimp body with scoop-shaped fins that cause it to spin in the wind, with a long tether that terminates on generator hubs on each end. The tether acts as a power line to a ground station that can extend or rein in the windmill-kite-blimp, to maximize its efficiency in changing wind conditions, or bring it to base in the event of severe weather.
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The author's affiliation with The MITRE Corporation is provided for identification purposes only, and is not intended to convey or imply MITRE's concurrence with, or support for, the positions, opinions or viewpoints expressed by the author.