Google has added $5 million to its investment in Makani Power. The California-based power company has yet to release details on the kits it uses to collect energy from high-altitude winds, but Google is banking on the start-up's ability to follow through on a promise for inexpensive energy.

Makani is the brainchild of Saul Griffith, a recent winner of a MacArthur grant. He expects the elevation will allow Makani to collect ten times the energy a traditional wind turbine could produce. The new investment brings Google's support of Makani up to $15 million. In October 2006, Google's Renewable Energy Cheaper than Coal (RE<C) program invested $10 million in Makani. Google also announced $10 million in investments in geothermal last week.

The market for wind energy — and the technology to provide it — is booming. In the U.S. alone, wind capacity increased by more than 27 percent. If Makani can get in on that market, Google's investment is guaranteed to pay off. It looks likely, too; Makani is the main company chasing high-altitude wind. Even if the idea of depending on a kite for power seems a little over the top to you, with Griffith in charge it seems very possible.

Image — Makani