10 Wacky Forms of Alternative Energy

Orbiting Mirrors to Transmit Solar Energy

You've probably witnessed the glee children experience when they see their reflection in one of those shiny mirrored balloons that are popular at birthday parties. Now, imagine an array of enormous versions of those party balloons -- perhaps as large as a mile in diameter -- deployed in geostationary orbit around Earth. Could they provide a possible answer to the world's energy shortage and climate-change woes?

In a 2007 article, the late Massachusetts Institute of Technology engineering professor William F. Schreiber proposed launching into orbit a fleet of such balloons, which would be activated by remote control to unfold and inflate. As the Earth's position changed with respect to the sun, the spherical mirrors would be adjusted continuously to catch and focus solar energy and transmit it in concentrated beams to receiving stations on Earth. At those receiving stations, that solar energy would be used to heat water into steam and drive turbines to generate electricity.

"The balloon approach is very attractive because it enables focus to be controlled by pressure [inside the balloon], rather than by making and then placing into orbit a very precise mirror," Schreiber wrote [source: Schreiber]. While Schreiber's idea for using giant shiny balloons may sound a bit outré, scientists increasingly have been looking at the possibility of using satellites to harvest solar power and transmit it to Earth. A study group from the Paris-based International Academy of Astronautics recently proclaimed: "It is clear that solar power delivered from space could play a tremendously important role in meeting the global need for energy during the 21st Century." And U.S. Air Force Col. Michael Smith, the director of the Pentagon's Center for Strategy and Technology, recently noted that the concept has the potential to supply safe, clean energy to the entire planet "if we can make it work" [source: Daily Mail].

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