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#Cathing #wind energy high on roofs
Energy Energy Wind

High on the roof wind search can help to make flats and offices completely independent of fossil fuel.
Wind poewerbox on top of a roof
One of the wind and solar boxes of the test project in Utrecht (the Netherlands).

In the city you cannot erect windmills. But a wind turbine fits on roofs. This can help to let flats and offices function fully on alternative energy.

Suma enters an apartment building in the Utrecht Overvecht district. He takes the stairs up, then the elevator to the highest point.
It is his sustainable dream that Suma - educated as an engineer - always brings to a dizzying height. He is the founder and director of the company Ibis Power, which places windmills on the roofs of flats and office buildings. No ordinary windmills, that's clear. On the roof of the seventies apartment is an elongated container. Inside is a rotating cylinder, which produces electricity on wind force.
Drawn windinstallation for roofs powernest
Ordinary windmills on a roof

"Putting an ordinary windmill on a roof does not work. That would be unstable, dangerous and against all building regulations. Putting a mini-windmill on a roof, you can. You see that too, here and there on buildings in cities. "They hardly generate electricity," Suma says. "Our mission is to generate enough electricity on the roof for all residents living underneath." It is possible, but then the houses do also need insulation and heat pumps.
Moreover, the entire roof has to be filled with the square turbines. A power nest, Suma calls them. The top of the square windmills has to be filled with solar cells, every square inch has to be used to generate green energy. "Only then can you provide an entire flat with it." And still not always. If there is no wind, or it is freezing, the houses still have to drain electricity from the electricity grid.

Getting rit of gas pipes

With the latest project, it must be possible to remove the gaspipe grid connection for six-and-a-half of the ten floors. The project in Utrecht is mainly a test; the electricity is for one of the houses in the flat. The prospects for Suma in Utrecht Overvecht are good, because exactly this neighborhood has been designated by the municipality as the first natural gas-free area.

The gas network has had its best time here. There must be no new gas pipes but clean energy. The Ibis Powernest costs 55,000 euros (excluding installation costs). That can be recouped in seven to fifteen years, says Suma, depending on the location. "Near the sea it is going faster, given the wind speeds, then near the central Netherlands."
Ibis Power works with six permanent employees, at an office in Eindhoven. The windmill of the powernest comes from Taiwan, the upright solar panels China. The company works together with a large construction and energy group for installation on roofs.

There are also companies that try to sell flat windmill boxes to the ridge of ordinary terraced houses.
Suma points from the roof of the flat over the houses and buildings. "They have to get rid of the natural gas as soon as possible." To arrange that, all sustainable technologies and alternative energy sources must be used, he says. Construction companies and municipalities are starting to get that through more and more. All buildings and houses must eventually become natural gas-free. Because of the climate agreement of Paris, and to liberate gas extraction area Groningen from quakes. But to make that change really a success, something has to change. The scale must go up, the costs down. In addition, some government regulations must change, Suma says. "Officially our wind energy roof still counts as an extra layer of living, which slows down processes." The tricky thing is also to distribute generated electricity well between all the underlying residential blocks.

Coast provinces

Apart from Utrecht, there is also a test mill on a roof in Nieuwerkerk aan den IJssel. Now that the attention for climate problems and 'Groningen' is increasing, the phone is constantly ringing at the company. Very different from ten years ago, when Suma started. He came up with the idea when he did PhD research in Miami, where air-conditioners were blowing all day. That made him think. "The energy consumption is cities is heavily polluting, that must be different." He also sees a sales market in the United States (New York), the Caribbean and Asia. Ibis Power wants to work internationally. Suma has just returned from Berlin, where he won a sustainability prize. He will soon have to go to the Chinese city of Shenzhen, where he also hopes to win the prizes.

In the Netherlands, the company mainly targets potential customers in the coastal provinces. There are the most energy-hungry buildings. "We already count 2,163 suitable buildings," Suma explains. The latest project will be in Rotterdam.
A ‘powernest’ must rake every bit of wind blowing in the city. Valves of the metal casing therefore press the wind through the opening so that it gets an extra swivel. "The wind speed accelerates to 160 percent of the original power," says Suma. "The funnel effect", he calls it.

Other turbines on roof
Tube windturbine
It sounds so unique, a reclining windmill on a roof. Nevertheless, Ibis Power is not the only one. There are some competitors who want the same, says Suma. "Our advantage: they have less practical experience." There is a Swiss company that sells the same kind of windmill roof, for flats and offices. They are nice and high. There are also some companies that try to sell flat windmill boxes to the ridge of ordinary terraced houses. They can also catch some wind and produce electricity, to feed the lamps directly. One appeared on a house in Vlieland (island in the north from the Netherlands), the yield was still thin.

Frank Straver