Three decades ago, there wasn’t a single offshore wind farm in the world. These days, there are over 100, the largest of which can generate enough energy to power 600,000 homes. What set off the winds of change? Vindeby, a €7.16 million project anchored off the southeastern coast of Denmark.

When Danish power company DONG Energy launched the 450-kilowatt offshore wind turbines project in 1989, it did so with big ambitions. Although the installation would take little more than a week, the planning phase had stretched over a full year as the utility worked with Siemens to develop and vet first-of-their-kind turbines. Onshore turbine nacelles, for example, let in outside air to cool their mechanical and electrical systems, but the offshore turbines would be damaged by the salty sea air. So the team developed an airtight nacelle that used a heat exchanger to cool the turbine’s machinery. To prevent corrosion, the team installed dehumidifiers, also creating a special crane for maintenance and repairs.

There was skepticism beyond the technological obstacles. “Many employees in the company didn’t believe in the idea of an offshore wind farm,” says Anders J. Jensen, who served as Siemens’ project manager for the design and installation. Doubters pointed to the unknowns of a pilot, including potentially high installation costs.

“I had to convince my colleagues this was possible.”

Anders J. Jensen

former Siemens project manager for Vindeby

“I had to convince my colleagues this was possible,” Jensen says. To win over his own team, he invited senior executives to the kickoff meeting to underscore the project’s strategic importance. Every so often, he reminded team members of the parallels between the Vindeby effort and other breakthrough initiatives, like sending the first person to the moon. “I told them that there had been other projects that no one could have anticipated 30 years earlier,” he says. “You never know what’s possible.”

The team eventually got with the program, even creatively finding cost-saving measures. For instance, rather than transport and install the turbines with jackup rigs (the de facto transportation for offshore oil drilling), the team opted for less-expensive barges. That decision had its own repercussions—since they were smaller, barges were more susceptible to the movement and potential damage caused by waves—limiting installation to no more than two turbines per 24-hour period in calm seas and none at all in rough weather. Even so, the team installed all 11 turbines in just 11 days.

The wind farm, which began operations in 1991, ultimately survived six years longer than its intended lifespan—operating for 25 years and powering about 2,200 homes over its life—and became a model for subsequent efforts. “The project was so successful in both the installation and the operation that it convinced politicians, planners and developers that offshore wind farms had a good future,” says Jensen.
In 2017, DONG, now called Ørsted, decommissioned and dismantled Vindeby. One turbine was moved to a display at the Danish Museum of Energy, while other components were reused as spare parts for similar turbines elsewhere.

Yet Vindeby lives on. The project’s core design elements, such as the corrosion-protection system, are fundamentally the same as those used in the much bigger wind turbines produced today by what is now known as Siemens Gamesa. While each Vindeby turbine generated 450 kilowatts, the new ones generate as many as 10,000 kilowatts. Another piece in a powerful legacy.