Floating Wind's Costly Tow to Rotterdam

Ninety-four days. That is how long one Kincardine turbine, KIN-03, was out of action between disconnection and the end of post-reconnection work, according to an analysis by Spinergie carried by Nacleanenergy. Of those days, 52 passed between the turbine being unplugged from its mooring and being plugged back in. Fourteen were spent at a quay in Rotterdam.

The heavy maintenance strategy was exactly as drastic as it sounds. The turbine and its floater were disconnected, towed across the North Sea, repaired, towed back and reconnected. That is the operation floating wind developers hoped to avoid and have learned to plan for. It matters now because the lessons from Scotland's pioneer floating farm are feeding directly into the next, much larger one, and the schedule for that project has already slipped.

A subsidy for an unproven machine

Grupo Cobra said on 11 January 2019 that it had begun commissioning Kincardine, 15 kilometres off the coast of Aberdeen. Cobra held 90% of the project, with local investors holding the remaining 10%. It said its aim was to show the park's commercial viability and to keep a minimum 20% stake once it was fully operational.

The economics leaned on subsidy. Grupo Cobra said Kincardine had a guaranteed rate of 3.5 ROCs, equivalent at 2019 prices to €190 per MW hour. The company described ROCs as a reward for a technology that had yet to show its profitability but was destined to improve on the production costs of conventional offshore wind. The pitch was straightforward. Fixed turbines cannot usually be installed in waters deeper than 55 metres, Cobra noted, while floating structures can reach areas with stronger wind.

The subsidy said nothing about how cheap the first machines would be to keep running.

What the first repair cost

Spinergie put numbers on it. For the first Kincardine repair campaign, vessels were hired at spot rates ranging from $63,000 to $210,000, and the total cost of the marine spread came to more than $4 million. The timing was unlucky. In June 2022, when the first Kincardine turbine was repaired, the largest bollard pull anchor-handling tug supply vessels were contracted at over $200,000 a day, which Spinergie called the highest rate in over a decade.

Then there was the quay. Spinergie wrote that the one used for the repairs was already busy as a marshalling area for other North Sea projects, which complicated the schedule significantly. Floating wind maintenance, it said, needs a port with enough room, a deep-water quay and a heavy crane with sufficient tip height to handle large floaters and reach turbine elevation. Few harbours tick all three boxes, and those that do have other customers.

Spinergie also sketched alternatives: a crane built into the turbine nacelle to lift a failed component straight off the floater, or self-elevating cranes working at the site.

Green Volt inherits the problem

Flotation Energy, which is developing the Green Volt floater off east Scotland with partner Vargronn, is studying Kincardine's operating history closely. Graeme Rogerson, the company's interface manager, told reNEWS that the floating nature of the Kincardine site, along with more regular turbine issues, explained the level of intervention needed in recent years. reNEWS said the site has seen various outages, even though all five units were spinning and generating the week before its report.

Those findings now go into the engineering of Green Volt's installation and operations methods. Flotation is weighing both in-situ repair and tow-to-port maintenance. Some experts argue that towing will prove too costly against fixing turbines at sea, reNEWS reported. Rogerson disagrees and expects both to be needed. For any future floating farm, he said, "you actually have to make sure that you're able to do both," a position the Rotterdam figures make easier to understand than to like.

The schedule is under strain too. Flotation and Vargronn have been working through the Gate 2 process with NESO, which reNEWS said has held up final procurement on the AR6-backed scheme and pushed the final investment decision from this year to 2027. Keith Johnston, Green Volt's supply chain manager, spoke to The reNEWS Podcast aboard a crew transfer vessel beside one of Kincardine's Vestas 9.5MW turbines. "We've certainly had some delays," he said. The delays, he explained, were around grid connections, and the offtake the project needs is now "somewhat resolved."

Flotation is aiming for key supplier decisions within six months of the report, which reNEWS dated 9 September 2026. That depends on pinning down final grid connection details and locking in the Kincardine lessons.

The price of getting it right

The government's latest auction shows what buyers will pay for floating wind. The Department for Energy Security and Net Zero published the outcome of Allocation Round 7 on 14 January 2026. Two floating projects won: Erebus in Wales at 100.00 MW and Pentland Floating Offshore Wind Farm in Scotland at 92.50 MW, both with phase-one delivery in 2029/30. That is 192.50 MW of floating capacity out of 8437.50 MW awarded in total, per the DESNZ results page.

Both cleared at 216.49 £/MWh in 2024 prices. The results page lists fixed offshore wind in England and Wales at 91.2 £/MWh in the same price base. The administrative strike price for floating wind had been 271 £/MWh, and the page shows a maximum saving of 20.11%.

A strike price that high is the market's way of pricing the risk Kincardine made visible: tugs at spot rates, a crowded quay, a turbine away from its mooring for weeks. Whether the next generation of floaters can be fixed more cheaply than the first will be settled in harbours and on the water, not in auction rooms. Flotation, for one, is betting that the answer begins with having two ways to get a turbine home.