Sky’s the Limit for Kite Power
Today’s wind turbines have a limit on how much electricity they can produce, which is partly because they can’t reach the altitudes where most of Earth’s winds is blowing.
They have designed large kites that can fly at altitudes between 1,640 to 3,281 feet (500 to 1,000 meters), where “strong and persistent winds blow practically everywhere in the world,” said Mario Milanese, founder of Kitenergy, an Italy-based company developing kite-power technology, and professor at Polytechnic University of Turin in Italy.
Recent studies in atmospheric dynamics have shown there is nearly four times more power available at these high altitudes than those accessible by wind turbines, Milanese said.
So far Kitenergy has built a prototype unit capable of generating 40 kilowatts (0.04 megawatts) of power. The company plans to have a 1-megawatt prototype in one to two years and commercial units in about five years.
The commercial kites, which would be about 10 times larger than the kinds used for kite-surfing, could potentially capture 5 megawatts of power, or enough to power 1,000 homes.
Here’s how the kites generate electricity: Each kite is connected with two cables to a generator – a device that turns mechanical energy into electricity – located on the ground.
When the wind blows, the kite flies in a figure-eight pattern creating a pulling force that drives the generator. Once the maximum length of the cables is reached, the kite retracts. Specialized software controls a steering device connected to the kite to continue this yo-yo flight pattern.
The kite’s flight pattern is “highly complex and difficult to control,” Milanese told TechNewsDaily.
That’s why kite energy, which was discovered in the 1970s, wasn’t realistic without today’s modern control technologies, he added.
Before the kites can be used commercially, the researchers now have to figure out how to keep them stable over the long-term.
If they can live up to their expectations, kites could rival other forms of renewable energy – wind turbines and solar panels, for example.
“Kitenergy technology is able to generate energy at half the cost of wind turbines and 10 times less than solar (and also at costs somewhat lower than coal and gas),” the company said.
While solar panels cost, on average, U.S. $377 per kilowatt-hours (kWh), Kitenergy costs an average of $30 per kWh.
Conventional energy such as that produced by coal and gas costs about $50 per kWh.