In 1991, the electricity industry largely considered offshore wind ludicrous. There was no offshore wind installation playbook, no jack-up fleet designed for the task, and no precedent for sequencing turbine erection at sea.
Vindeby, commissioned that year off the coast of Lolland, Denmark, became the world's first commercial offshore wind farm anyway — built not with purpose-designed offshore equipment, but with harbour construction logic and mobile cranes.
No offshore wind installation playbook, no jack-up fleet, no precedent — Vindeby's foundation logic came from lighthouses, not from any wind industry that existed yet.
Vindeby operated for 25 years, several years beyond its original design horizon, before decommissioning in 2017. The float-and-ballast sequence pioneered here — settle a gravity-base structure under its own increasing weight rather than pile or lift it into place — remains recognisable in how some gravity-base foundations are installed today, even as the industry has since moved to purpose-built vessels working in far deeper water.
For further reading on offshore wind foundation methods, see What is Heavy Lift Engineering?
Related case studies: Borssele · London Array · Horns Rev 1
Sources: Ørsted — owner's decommissioning announcement, confirming the 1991 grid connection, 11 turbines, and one-piece installation; Vindeby Offshore Wind Farm — capacity, water depth and lifetime output. Figures are reported as published.
Frequently Asked Questions
Commissioned in 1991 off the coast of Lolland, Denmark, Vindeby was the world's first commercial offshore wind farm, built at a time when the electricity industry largely considered offshore wind impractical and no offshore wind installation playbook, jack-up fleet, or turbine-erection precedent existed.
The foundation solution was reportedly based on established lighthouse construction logic. Concrete gravity-base foundations were cast in an artificial dock built nearby, the dock was flooded, and each foundation was floated out to its position and progressively ballasted until it settled onto the prepared seabed under its own increasing weight. A concrete slab was then cast on top to form the turbine base.
Vindeby was built with harbour construction logic and mobile cranes rather than any purpose-built offshore wind installation vessel, which did not yet exist in 1991.
Vindeby operated for 25 years and was decommissioned in 2017, several years beyond its original design horizon.