Kitemill’s airborne wind turbine harvests the energy of high-altitude winds, increasing efficiency and reducing carbon emissions. “We use the kite principle to collect new wind power much higher up than conventional wind turbines,” says Thomas Hårklau, founder and CEO of Kitemill.
The wind power market has taken off in recent years, and wind power is considered the most important production technology to meet our global net-zero targets.
However, conventional wind farms have their shortcomings. The biggest challenges are space requirements, high material usage and the intermittency of power production.
“Conventional turbines cannot be built tall enough to reach the strongest, steadiest winds,” explains Hårklau.
Kitemill has developed an airborne wind system featuring a kite turbine that accesses winds 500 to 1500 metres above ground level, where the winds are strongest, steadiest and most predictable. The system consists of three main parts: the kite, the tether and the ground station.
Together, they generate energy through a simple, yet effective principle.
The kite is fastened to a tether, which is reeled in and out by a winch. The tether transfers the lifting force of the kite to a ground station generator, which converts the tether’s tractive force to electricity. The electricity, in turn, is fed into the power grid.
A sensor-based control system ensures safe flight and optimal energy production.
“We can handle the same amount of output as regular wind turbines, with less than 10 per cent of the materials,” says Hårklau.
Moreover, the kite turbine is expected to reach five times higher energy density than conventional wind.
Kite turbines are more efficient than conventional turbines of the same scale. Kite turbines reduce losses and reach full power in less wind, two factors that give a better efficiency rate. Higher efficiency and access to better wind resources produce more energy relative to installed capacity, known as the capacity factor.
In addition, Kitemill’s turbine requires no infrastructure other than a grid connection. Compared to conventional turbines, it has a smaller carbon footprint. “We estimate that our turbine will reduce annual CO2 emissions by 10 gigatonnes from 2050,” says Hårklau.
It also intrudes less on the landscape and can be removed with few traces.
Although in its infancy, airborne wind energy is considered a promising market. Kitemill’s system could pave the way for wind power generation in new regions, as winds at altitudes above 500 metres are found around the globe. Installation of the turbine could be an alternative to the repowering of old onshore and offshore wind farms, and may be suitable for use in floating offshore wind as well.
Kitemill’s airborne wind energy system has demonstrated autonomous operation in all modes, and will be scaled up to utility size.
A 20 kW system is currently in field testing. A 100 kW system is under development and will become the first commercial solution. Kitemill is ready to conduct demonstration projects in new markets.
“Kitemill is part of creating a more sustainable society. We will play a significant role in achieving an emissions-free society by 2050,” concludes Hårklau.