High-flying kites could power your home with wind power
For Florian Bauer, co-CEO and chief technology officer of Kitekraft, a Munich-based company developing a flying wind power system, the fight against climate change is personal.
“It all started during my school days when I read Al Gore’s book and saw his documentary ‘An Inconvenient Truth’. It triggered and encouraged my decision to study renewable energy because I I felt like I could help solve the problem by being an engineer.” he says THAT IS TO SAY in a video interview.
Today, Bauer, along with André Frirdich, Christoph Drexler and Max Isensee, are changing the direction of renewable wind energy with Kitekraft. The company builds flying wind power plants that include a tethered electric aircraft called a kite. The kite has wind turbines on board and flies in a figure eight to generate electrical power from the wind.
Although flying wind turbine technology is still in its infancy, several companies around the world have decided to explore airborne wind energy and flying power plants.
Green signal for wind power
With net-zero emissions in sight, the International Energy Association (IEA) says nearly two-thirds of global electricity generation must be renewable by 2030 to meet the Paris Agreement’s 2050 targets . Moreover, wIndustrial energy is expected to increase 11 times by 2050 and will certainly play a key role in future electricity generation.
According to the International Renewable Energy Agency (IRENA), the global installed capacity of onshore and offshore wind farms has increased nearly 100-fold over the past 20 years, from 7.5 GW in 1997 to 743 GW in 2020. , with 93 GW of new capacity installed in 2020 alone – a 53% year-on-year increase.
The expansion, accelerated by growing demand for cleaner energy sources, has led to a reduction in the cost of wind energy, which has fallen by around 40% over the past decade and is expected to continue falling.
Reducing costs could make renewable energy even more accessible. This is where the power of the kite comes in.
Harnessing sustainable energy
But what is a kite-powered system and how does it generate power?
A kite-powered system usually consists of a kite with rotors, a tether, and a ground station. As the kite flies through the air, the rotors spin, harvesting energy from the wind, while the tether that attaches the kite to the ground station transmits electricity to the ground. The ground station, in turn, stores energy in batteries or feeds it into the grid.
“From a technical point of view, it’s extremely interesting. You can combine aerodynamics, electrical engineering, electronic control, software engineering, etc. It’s also an interesting business case,” says Bauer.
Unlike fixed wind towers that require concrete and steel structures, kite-based systems have a lightweight tether and small ground station, requiring 90% less hardware. “The benefits flow from that,” says Bauer.
This was illustrated in a study by Airborne Wind Europe – which found that a 50 megawatt kite park would use 913 metric tons of material over a 20-year lifespan, compared to 2,868 metric tons for a park typical wind.
Kitekraft kites are mainly made of aluminum, which is easily recyclable. In contrast, materials typically used in conventional wind turbines, such as steel and carbon or glass fiber reinforced plastics, are difficult to recycle. Although Kitecraft’s rotors are made of carbon fiber, their small size makes it much easier to recycle the blades.
“As a result, it is easier to manufacture and transport, and the carbon footprint is significantly lower. This is one of the problems the wind industry is currently facing. emits carbon. The prices of concrete and steel are also high,” explains Bauer. “We use 10 times less material compared to conventional wind turbines to obtain the same unit of energy.”
Kitekraft kites are equipped with eight motors that power the device during take-off and landing. They are then used as generators during flight. An electronic power control unit stabilizes the kite and generates power efficiently.
“Basically, the kite is a tethered multicopter,” says Bauer. The figure-eight pattern created by the kite represents the most efficient part of a conventional wind turbine. “The tips of the blades produce most of the wind energy.” Wind energy can be produced at relatively low installed capacity, starting at 100 kilowatts.
The company completed successful autonomous flight tests last year, which it described as “a major step towards our first 100kW product”.
Although the kite is still in its prototype phase, it could eventually be a boon to remote areas by bringing renewable energy to those living off the grid. Moreover, kites could come to the rescue in places where the erection of massive wind turbines is impossible.
Considering all the benefits of a kite-powered system, it may seem like there’s no reason to build a conventional wind turbine.
However, “it’s much harder to build the kite,” says Bauer. “Comparatively, the wind turbine is much simpler – it’s just a tower. You have to master all the technology to build the kite. Many of our competitors have been trying to solve the problems for many years. Overall, there are several technologies and business barriers.”
But will it take off?
“We are in conversation with many potential customers who expect us to prove reliability and efficiency. What we are happy about is the fact that people are aware of the benefits and cost-effectiveness. This also helps that it has low visibility, which makes it almost invisible,” he says. This could help communities that have opposed wind turbines because they see them as eyesores.
Over the next year, Baur hopes to solve the problem of autonomy to prepare the actuators and sensors. “We also want to reduce software redundancies so that we don’t have a single point of failure,” he says. Additionally, the technology is also better suited to hurricane-prone areas, as the kite can be lowered to the ground rather than risk being damaged by high winds.
But, of course, scaling is not easy. Although smaller kites are cheaper and easier to develop and deploy, they will not operate effectively at around 300 meters (984 feet), where the winds are often strongest. Developing larger kites with more power comes with a risk that needs to be carefully calculated.
“Our market entry product would be a 100 kilowatt kite with a wingspan of 33 feet (10 meters), which we hope to ship by 2024. If all goes well, we will scale up. The next kite would have 500 kilowatts of power with a wingspan of 65 feet (20 meters). Doubling the kite wouldn’t just double the power – instead, you’d get five times more,” he says.
“One possibility we are looking at is kite farms, just like wind farms. It could be both offshore and onshore,” he says. To use them offshore, all you need is a ground station, such as a floating buoy. Kites can be lowered if the winds get too strong. “We could also use them on microgrids in regions like deserts,” adds Bauer.
It is still unclear to what extent kite-based wind power will become widely used. However, once engineers solve the engineering and computational problems that are preventing kites from being used more widely, airborne wind power could be the answer to the electrification of the future.
Editor’s Note: This is part of our series PLANET SOLVERSor THAT IS TO SAY explores climate challenges, solutions and those who will lead the way.
Check out the other stories here: a wooden freighter that sails without fossil fuels, a hydroelectric panel that produces clean water from air and sunlight, a tower that turns pollution into diamonds, and a super -tree genetically modified to better capture carbon.