Despite the stiff economic headwinds that are usually encountered with wind-power projects, Makani Power, Inc.’s flying, tethered, wind turbine could beat the odds. Corwin Hardham, CEO and chief technical officer for Makani, says kiting, a much lighter wind turbine positioned at higher altitudes, where wind is more brisk and consistent, changes the economics of wind-power production.
Designed to use strong, light composites made of mostly carbon fiber, the Makani Power turbine soars in a circular motion, like a kite, while tethered to the ground. The electricity generated from the turbine’s blades flows through the tether. The turbine operates at a much higher altitude than a tower-mounted turbine, using just 10 percent of the material typically used in a pole-mounted wind turbine, says Hardham.
“Wind turbines onshore are about 100 tons a megawatt (MW), and for us, our wing weighs about two tons per MW, and then we have somewhere around eight tons in the ground-station support equipment,” he says. “These are very rough numbers, but it will give you an idea of that 90 percent reduction in mass.”
“There’s a lot of enthusiasm about this and it’s partially because of the dramatic cost reductions we offer, particularly in terms of cost to energy,” says Hardham. “We’re talking about being able to get down to three cents a kilowatt-hour (KWh), and offshore somewhere between six and seven cents per kWh,” he says.
“Onshore you’re below grid parity for conventional generation, and offshore, you’re quite close to it. So, given the fact that there’s about 20 terawatts of wind energy available across the United States, this technology has that ability to really supply massive amounts of energy.”
According to multiple news re- ports, Google.org has invested $15 million in Makani Power. The U.S. Department of Energy also contrib- uted a $3 million grant for the pilot project through the department’s Advanced Research Projects Agency. “We will need more capital to support the privatizing of the technology we’ve developed and actually carrying that through to commercialization,” says Hardham.
The 30-kilowatt system has dem- onstrated all modes of flight — “the essential functionality of what will be needed for a commercial system,” Hardham says. The company expects to have a 600-kilowatt turbine deployed in wind farms, and potentially even offshore, within five years, says Hardham. He says the ideal location for the company’s wind turbine is deep water offshore, although the turbine would also function well within a conventional wind farm. “Offshore we have an even more significant mass and cost benefit, which is driven, partially again, by the reduction in materials for our system, as well as some ways in which we are able to fly it from a buoy.”