Agile Wind Power’s Giant VAWT Coming Down

By Paul Gipe

Agile Wind Power is removing its giant VAWT from the Grevenbroich test site. The dismantlement follows the second failure of the test turbine.

The Swiss company has been developing the mammoth giromill for the past decade. The prototype has been undergoing tests at Grevenbroich for the past three years.

The turbine previously lost one of its three rotor arms in November 2020. The Vertical-Axis Wind Turbine (VAWT), one of the largest ever built, was reinstalled in August 2022. Testing began again when the turbine was reconnected to the grid in October 2022.

However, within six months the rotor was again damaged. In a press release 1 June 2023 Agile Wind Power acknowledged that “Dismantling work on the damaged rotor began in mid-March” of this year. But the “work had to be interrupted due to high wind speeds.”

Worse was yet to come for the erstwhile manufacturer. Schweizer Bauer (The Swiss Farmer) reported 26 March 2023 (Windkraft: Rotorarm an Testanlage abgeknickt) that the VAWT test turbine broke a rotor arm the previous day.


Photo by Thilo Wirth, Cologne.

According to their report, the rotor arm had previously been damaged and the manufacturer was in the process of removing the affected blade and rotor. During high winds the rotor arm failed even though the turbine was not operating at the time. The rotor arm fell into the tower, damaging the tower.

Fuerwehr Grevenbroich Agile Wind Power

Agile Wind Power Vertical Sky 32 second rotor arm failure. Photo by Fuerwehr Grevenbroich.

Local emergency services then cordoned off the area around the wind turbine until a safe way to remove the rotor arm and blade could be determined.

The test field at Grevenbroich is in the lignite mining region west of Cologne, Germany.

The H-configuration VAWT at Grevenbroich was 32 meters in diameter and each straight blade was 54 meters long, giving the machine 1,730 m² of swept area.


Vertical Sky® A32 at the German test field in Grevenbroich. Agile Wind Power.

Vertical Sky 32 is the largest H-configuration or giromill wind turbine ever built. It is twice the size of Robert McAlpine’s Musgrove derived VAWT 850 built in 1990. And Sky 32 is bigger than the last French effort, Nenuphar 1, which went belly up after Areva and French state-owned utility Électricité de France abandoned the project in 2018. It is also slightly bigger than the three-blade, fixed pitch, H-rotor built by Stahlprodukt in Poland in 2017. However, it is less than half the size of Éole.

Agile Wind Power Vertical Sky 32.

Vertical Sky® A32 at the German test field in Grevenbroich. Agile Wind Power.

Éole, a Φ-configuration Darrieus turbine, remains the largest VAWT ever built. Éole swept 4,000 m² of the wind stream. At last report the monster Darrieus turbine was still standing at Cap Chat in Quebec. Though it has not operated for several decades, the turbine has become something of a local tourist attraction.

While Sky 32 is a marvel of Swiss engineering, the latest accident can’t be good for Agile Wind Power’s prospects. The June press release was a Swiss version of the British “stiff upper lip” as it described the company’s next steps if indeed there are “next steps.”

Though the technology once held promise, there are no commercial-scale VAWTs–of any variety–on the market today. Worse, small-scale VAWTs have become the domain of internet hucksters and charlatans.