VentureBeat

Stealth startup Makani Power, an Alameda, Calif.-based wind energy company, has secured $5 million in second round funding from returning investor Google.org. The 24-member firm, which is playing its plans very close to the vest, has only revealed that it is building huge wing-shaped kites to harness the energy from high-altitude wind.

By some estimates, all the energy contained in wind could satisfy our needs 100-fold, with most coming from high-altitude wind. Tapping into just 1 percent of this energy could meet most of our current needs. In a recent demonstration, scientists from the Netherlands’ Delft University were able to produce 10 kilowatts of electricity by flying a 10-square meter kite attached to a generator.

A kite farm, consisting of multiple kites flying at altitudes of around 800 meters, could generate up to 100 megawatts — enough to power 100,000 homes — they say. Wubbo Ockels, the project’s leader, believes the technology could be commercially viable in as little as 5 years if the funding is there.

Makani also aims to capture that small slice of global high-altitude wind, which it says would be sufficient to supply the world’s current energy needs. The kites capturing the wind could fly as high as 10 kilometers into the sky (a touch over six miles).

As a competitor, Makani has Kite Gen, a Milan, Italy-based startup, has developed a theoretical design for a system that would fly 12 sets of lines with four 500-square meter kites on each. It says the system could produce up to 1 gigawatt of power, roughly equivalent to the amount generated by a coal-fired plant. There’s also Magenn, which has a lighter-than-air floating turbine, although it will only go up 600 to 1,000 feet.

Makani previously raised $10 million from Google.org in late 2006 and expects its current round to raise upwards of $20 million.

Google.org, Google’s philanthropic arm, has taken a number of stakes in solar and wind startups over the past year, most recently joining a $115 million investment in solar thermal firm BrightSource Energy. It now seems to be focusing its attention on the bustling geothermal energy sector, with Google co-founder Sergey Brin recently expressing a strong interest in Ormat, a geothermal startup headquartered in Reno, Nevada.

During an interview with the Israeli newspaper, The Marker, Brin confirmed that his company was in discussions with Ormat to collaborate on several clean energy projects, calling the startup a “great company” and praising it for its potential to turn geothermal energy “into a big business.” Though he wouldn’t say whether Google was in talks to purchase any Israeli cleantech companies, he did say that the conditions were good for his firm to buy companies in 2009. He said there were a lot of interesting companies that worked in renewable energy and electric cars — perhaps a nod to Shai Agassi’s Project Better Place.

According to Haaretz, senior executives at Google have already met with their counterparts from Ormat twice, and Larry Page recently visited one of the company’s plants in Steamboat Hills, Nevada. Ormat chairman Lucien Bronicki said he and Google officials were pushing legislation in the U.S. advocating more R&D for advanced geothermal technology. Ormat announced in February that it would work with the DOE and several geothermal companies — GeothermEx and Pinnacle Technologies — to test Enhanced Geothermal Systems (EGS) technology at its 11 megawatt Desert Peak facility.

The DOE has committed $1.6 million to support the project, which could eventually yield over 50 MW of power. The partnership will test hot fractured rock (HFR) technology to attempt to increase the output of its geothermal wells. Sydney, Australia-based Geodynamics, which I wrote about a few weeks ago, has been on the forefront with this technology and is nearing the completion of a 50 MW demonstration plant to supply up to 75,000 people by 2012.

Ormat has several existing projects in Guatemala, Kenya and Nicaragua is considered the world leader in geothermal energy.

In addition to making a series of high-profile investments in eSolar, BrightSource and Makani Power as part of its RE<C initiative, Google has also donated over $1 million in grants to support plug-in vehicle adoption. The foundation’s RechargeIT initiative recently gave $200,000 to CalCars.org. Page said Google.org’s goal is to produce 1 gigawatt of renewable energy capacity from wind, geothermal and solar thermal sources cheaper than coal, an objective he and Brin are optimistic will be met in years, rather than decades.