Engineers in 2009 set a 5,000-ton steel box on stilts in the German Bight and asked it to do something nobody had ever asked an offshore platform to do: take 400 megawatts of wind-generated alternating current, convert it to direct current at 150,000 volts, and push it 200 kilometers through a cable to a substation called Diele. BorWin Alpha became the first HVDC converter station in the world to live on an offshore platform. It also became the first to teach the industry, sometimes painfully, what could go wrong out there.
BorWin Alpha was born inland, in a shipyard in Vlissingen on the Dutch coast. Inside its 5,000-ton hull, ABB engineers packed IGBT-based voltage source converters, transformers, switchgear, and the climate control needed to keep all of it alive in salt air. At the end of May 2009, the heavy-lift crane vessel SSCV Thialf - one of the largest in the world - hoisted the platform onto its jacket foundation in the German Bight. The finished platform stands 84 meters tall, 62 of those meters in the jacket alone. From a passing flight, it looks like a steel cottage on a steel water tower, alone in open water, 130 kilometers from the German coast.
The North Sea wind blows hard and reliably, but the wind is offshore and the cities are inland. Run conventional alternating current that far through a submarine cable and the cable itself starts behaving like a giant capacitor, swallowing the power you are trying to send. High-voltage direct current solves the problem. BorWin1 was the first such link in the world built specifically for offshore wind, and the first in Germany to use voltage source converters - a more flexible technology than the old thyristor-based schemes, capable of starting up on its own and supporting the grid at both ends. It opened a path that every German offshore cluster has followed since.
The pioneer paid for the privilege. BorWin1 was supposed to carry the entire 400 MW output of BARD Offshore 1, the wind farm directly behind it. Instead, vibrations and harmonics on the DC side caused damage that took years to track down and fix. In March 2014, a fire on the platform shut the scheme down for months. The German regulator and TenneT, the transmission operator that inherited the project, argued with manufacturers and wind farm owners about who would pay. By the time the next BorWin link came online, BorWin2 had quietly passed it - commissioned in 2014 and handed over in January 2015, while BorWin1 was still being patched.
Today the German Bight bristles with HVDC platforms - DolWin, HelWin, SylWin, and the later BorWins - each carrying more power than the last. They exist because BorWin1 went first and discovered, the hard way, what worked and what did not. The platform still stands in roughly the same patch of sea, doing the same job it was designed for, only with hardware lessons absorbed into every successor that came afterward. It is engineering history with a beating heart of solid-state switches, still humming inside its steel box.
BorWin Alpha sits at 54.35°N, 6.03°E, roughly 130 km north-northwest of Emden and about 110 km north of Borkum, in the German exclusive economic zone of the North Sea. Nearest land airports: Emden (EDWE) to the south, Wilhelmshaven (EDWI) to the southeast, and Heligoland (EDXH) to the east. Best viewed from 8,000-15,000 ft on clear days, when the lone platform stands out against open water; the surrounding BARD Offshore 1 turbines form a circle of white pillars around it. Watch for restricted airspace around active wind farms.