Vertical-axel windmills need fewer moving parts than traditional designs, keeping maintenance costs lower.

Vertical-axel windmills need fewer moving parts than traditional designs, keeping maintenance costs lower.

Turbines with blades that revolve on a vertical rather than horizontal axis can improve the efficiency of clean wind generators, according to the Swedish manufacturer Vertical Wind. Based in the university town of Uppsala, north of Stockholm, Vertical Wind aims to become the nation’s first exporter of wind power generators.

The Vertical Axis Wind Turbine, or VWAT, is not a brand new idea, nor is it unique to Vertical Wind. But while other manufacturers have been on the market longer, the Swedish company believes its solution is superior because of its robust construction and precise design.

VWATs offer a number of advantages compared to turbines with the traditional horizontal axis:

  • They do not need to face into the prevailing winds, eliminating the need for a yaw mechanism.
  • The generator itself can be placed on the ground, where it can be made larger and is easier to service.
  • The generator is driven directly, eliminating the need for an extra gearbox and improving generating efficiency.
  • Because the supporting tower does not need to support the generator and gearbox, and because the blades are much lighter, the tower can be less massive, reducing impacts on views and on nearby radar installations.
  • With horizontal drives, the tall towers and blades (up to 90 meters long) are difficult to transport. Transportation costs can be as much as 20 percent of the construction cost.
  • VWATs are much easier to install than their horizontal cousins, since they don’t require tall and expensive cranes and skilled operators.

And VWATs require fewer moving parts. “The more parts, the more that can go wrong,” says Vertical Wind CEO Björn Hellström. “We make it as simple as possible. Only a single unit needs to move.”

Research in several fields

Vertical Wind is an outgrowth of the Division for Electricity at Uppsala University, where wind power research has been conducted since 2001. The company was founded in 2002 by professors Mats Lejon and Hans Bernoff; several of the company’s employees supervise doctoral candidates at the university. Hellström, who holds a civil engineering degree from the Royal Swedish Institute of Technology (KTH), got to know the founders when they worked together on energy and development issues at the electrical engineering firm ABB. Hellström is a founder of Sensimor, which produces sensors for the semiconductor industry.

Vertical Wind began with careful preparatory work in several fields of research, including aerodynamics, solid mechanics and electro-mechanical design, as well as meteorology and environmental planning—work that continues in close cooperation with the university. Development operations constitute the bulk of the young company’s early-stage activities.

Vertical Wind received a patent in 2002 for its combination of vertical-axel blades and generator location. A pilot 12 kW turbine came online on a cold December morning in 2006, setting the stage for continued development.

The first commercial order came in 2007 from the telecom equipment giant Ericsson, looking for a new way to power its remote mobile network base stations. The idea is to be able to expand the cell phone network to regions in developing countries not reached by electric power grids.

The German electricity provider E.ON and Sweden’s Falkenberg Energi order four 40-meter wind power stations for a prototype generating park. With blades of 24 meters, the windmills will generate some 200 kW each. The Swedish Energy Agency has judged the technology promising enough to warrant a support package for the project of SEK 10 million (USD 1.4 million). The first generators are under construction at Uppsala University.

Vertical Wind has won considerable attention from the Swedish press, including the technology magazine Ny Teknik and the business weekly Affärsvärlden, which has listed the company among the country’s 33 most promising technology enterprises. The Worldwide Fund for Nature (WWF) includes Vertical Wind among the 12 most important Swedish companies addressing climate change. And the outgoing US ambassador to Sweden, Michael Wood, sees Vertical Wind as one of the country’s most promising investments.

“Yes, we’re looking for investors,” Hellström says. “But they need to have a long-term perspective.”

Development plans call for construction of 100-meter windmills in about three years, generating 1 to 3 MW apiece. Swedish energy planners expect to see up to 3,000 new wind generators in operation by 2020, while as many as 12,000 could be built in Germany and England are. Vertical Wind aims to grab a substantial share of this growing market, while acknowledging that the challenge is to convince operators of the superiority of the vertical-axis construction.

“The big picture is that our competition is every electricity producer,” says Hellström. “But if you look at the type of wind power we work with, you see that no one is making large-scale vertical-axel windmills today, or at least none that we know of.”

Hellström’s goal is to make Vertical Wind Sweden’s first successful wind power manufacturer. “That’s the owners stated intention,” he explains. “And that’s why it’s so exciting to work here. We’re ramping up a Swedish manufacturing industry for wind power, and we’re going to compete with the big guys.”

Article published in October 2009