Photos: The Laddermill team testing their new power-kites. See a full video here.
Want renewable power? Go fly a kite.
“Today, wind turbines are the cornerstones for the transition from fossil fuels to renewable energy provision,” says Roland Schmehl in his talk at TEDxDelft in the Netherlands. But they are not without their problems, he admits. There’s the threat to wildlife, the noise, the lack of mobility.
So, he’s proposed a solution: kites.
Above: Roland’s talk — “Finally, kites have grown up.”
As a member of the Applied Sustainable Science, Engineering and Technology (ASSET) Institute at Delft University of Technology, he is a part of the Laddermill project — an effort to create giant kites that serpentine the sky to collect kilowatts of power in the double digits, if not more.
A prototype of the Laddermill collected 10 kilowatts of power on a test run, “enough electricity to power 10 family homes,” according to The Guardian, and it has been predicted that a collection of Laddermill kites could possibly capture 100 megawatts of power — enough to power 100,000 homes.
“The bigger you build a [tower-based wind] turbine,” Roland says in his talk, “the more efficient you can make it… the higher you reach with the turbines, the higher the energy density that you can harvest. But there is obviously a limit. Although we’ve built turbines that are approaching the wingspan of an Airbus 380 — there is a limit. It is a structural limit. We simply cannot build tower-based turbines that can actually reach into several hundred meter altitudes.”
This is where the kite comes in:
“The [tip], the last 25% of [a wind turbine] rotor blade actually makes more than 50% of the energy,” he says. “So why don’t we decouple the rotor blade from the hub and actually move it — as a free-flying wing — into the air?”
“The kite system can adapt itself to the altitude where the actual wind power is — so if there is little wind at the ground, we just fly higher, where the wind is typically stronger. If the wind is too strong, we can go lower again…
We put the generator onto the ground; we connect that with a very strong and lightweight tether, which actually converts the traction force of the wing — transmits that to the generator — to convert to electricity.
[And] it can be used, for example, for remote applications: development areas, disaster areas, all these places where you need energy quickly and you don’t have oil — or fuel.”