Have you ever wondered that kites can do a lot more than engage little children who love to fly them in the sky? Well, interestingly, they are not just a child’s toy but also a subject of interest to scientists who have always been in search of tapping new sources for supporting our ever-increasing electric needs.
Winds at a high altitude of 200 meters (656 feet) and more are stronger and steadier than the wind close to the surface. These winds are strong enough to generate more electricity than required and surprisingly can produce more than what wind turbines produce on land. Theoretically, when the speed of the wind is doubled, it can generate up to eight times more power.
Moritz Diehl, head of the Department of Microsystems Engineering at the University of Freiburg, said that making use of high-altitude winds was among the “most promising” technologies for producing renewable energy in the future. He added, “You see all the sky above conventional turbines, and you think all this wind energy is just blowing there and it’s not used.”
Stephan Wrage, CEO of the German wind power company SkySails-Power, seeks to change this and make the “largest yet untapped source of renewable energy worldwide” fit to be used by masses.
But he isn’t the only one who thought of it. It has been years that engineers, several startups, and international companies have been racing to bring high-altitude winds to the Earth feasibly. Though some have failed in their attempts and have even gone bankrupt, but others are at the peak of coming into the market with their flying power plants.
Flying wind turbines and other ideas
In 2010, the first company to execute this was the US energy company Altaeros. Their prototype included a generator attached to a helium balloon, meaning a wind turbine without a heavy base and tower.
The prototype was tested in Alaska where it was held to the ground by a cable. At a height of 600 meters, it generated energy for around 50 households, according to the company.
Simultaneously, SkySails, a German company, came up with a high-altitude kite that pulled entire container ships. This was done to save diesel, used to run the engine, up to 10%.
Though the test worked, the shipping company went bankrupt and the kite and the helium wind turbines were not a success in the market. But both prototypes had something in common, high-altitude winds required flying power plants.
It worked, until the crash
In 2013, the tech giant Google acquired the US airborne wind energy company Makani for an undisclosed amount, which stimulated exhilaration in the sector. The flying power plant, a device about the size of a small aircraft, went up to an altitude of about 300 meters and it circled in an ongoing and automated loop.
The high speeds motioned the small wind wheels on the wings, thus producing electricity. Moritz Diehl thought it would be “crazy” at the time, but it worked. According to Makani, one flying power plant produced energy for 300 households.
It marked a breakthrough that everyone was hoping for until a device crashed into the sea during a test mission. Alphabet, Google’s parent company, closed down the project having doubts about the economic viability of the flying power drone.
Another beginning
The end of Makani did not put an end to airborne wind energy. Several startups continued to work on small devices that required less material. Some were inspired by Makani’s approach, while others chose to attach drones to a rope that pulled the generator. Some of them went on with the same approach but used a drone instead of a kite.
Among them is SkySails-Power, successor to the bankrupt German company, behind the towing kites. For energy generation, SkySails-Power has developed a device that uses a “pumping cycle” for power generation. The kite takes off from the ground automatically and goes against the wind and unwinds a rope from a generator. It flies in figure eight, constantly pulling the rope and generating energy.
The kite is developed for staying airborne for hours, days, and weeks. An alarm goes off during bad weather or dangerous conditions and the kite can be recovered.
Not designed to replace existing wind power
Regardless of the lack of investment and compliance with many regulations around air traffic, Stephan Wrage states that the technology will benefit the 1.4 billion population who live without electricity and use diesel generators to get electricity.
A study by the members of the wind industry states that airborne wind energy will be more cost-efficient than diesel and even cheaper than traditional wind energy.
Wind Energy In Africa
The current leader in the sector, SkySails-Power has made its first sale to Mauritius. To operate offshore kite wind farms, the company aims to build a high-altitude wind hub in East Africa. SkySails claims that a single unit of its Kites can provide electricity to up to 500 households while consuming 90% fewer materials than traditional windmills. Another advantage is its flexibility of location.
Diehl states, “You could also operate them above the forest. You could stop them operating and or even land if there’s a swarm of birds passing by.”
“It will still take a few years” before the technology makes a difference. “The wind industry also took around 40 years to develop to be this cheap”, Rishikesh Joshi, an aerospace engineering researcher at the Delft University of Technology, said.
Meanwhile, the traditional turbines continue to work. Even after advancement in the Airborne Wind Energy Sector, traditional turbines won’t be replaced; instead they’ll be used for more efficient utilization of winds that blow high above the ground.
