The flow of rivers can help generate electricity.
So too five long, curved tube halves. At least, according to the patented design of a Lisbon-based startup.
The parts are fastened to a pole, making a low-maintenance wind turbine. As the technology is scalable three sizes of the noiseless, aerodynamic turbine are planned.
A small 100W generator, 1.2 metres tall; a second, twice as big and ten times as powerful; and a third, 8 metres high and generating 10 Kilowatt.
All models produce electricity once wind speed reaches 2 m/s and can withstand gusts of 90 km/h.
Work is also underway in Berlin to produce mini wind turbines. A Norwegian startup, meanwhile, is aiming higher.