Wind wake fears prompt Germany to cut turbine density in new marine masterplan
Maritime agency cuts density at offshore wind sites to be offered in tenders after phenomenon was blamed for lack of interest in recent round
Germany has updated its marine spatial development plan to lessen the impact of wind wakes on future offshore wind farms, in a signal that the issue is climbing up the agenda for policymakers and the renewables industry.
The German Federal Maritime and Hydrographic Agency (BSH) has in its new plan split up some of the larger areas available for offshore wind and cut turbine density at sites to be offered in upcoming tenders.
The measures are designed to increase the potential number of bidders at future auctions and reduce potential wake effects. Wind wakes are trails of lower intensity wind that turbines leave trailing behind them which can reduce power generation at neighbouring sites caught in their shadow.
“I welcome the fact that the Federal Maritime and Hydrographic Agency has listened to our wish for a division of larger areas in the new area development plan. This can have a positive effect on the diversity of players and promote healthy competition,” said Stefan Thimm, BWO's managing director.
“The lower power density of the wind farms in areas that will soon be put out to tender is good news. It will enable the planned projects and the offshore wind farms in their ‘wind shadow’ to harvest more wind power and thus increase the amount of electricity from offshore wind in the North Sea.”
Martin Dörenkämper, head of the numerical yield and site assessment group at German research body Fraunhofer IWES, which has helped officials address the wake issue, said: "Since 2021, we have been scientifically supporting the BSH in the update process of the area development plan through intense wake scenario calculations using a mesoscale modelling approach.
"This also included an enhanced validated wake parametrisation that... went from science to industrial application."
Push towards 70GW by 2045
The spatial development plan (FEP) outlines spatial planning for Germany’s exclusive economic zones in the North and Baltic Seas, aiming to develop offshore wind energy and grid infrastructure in a way that renders the country’s 70GW offshore wind target by 2045 possible.
The plan presented Thursday defines and expands designated offshore wind areas for development, and establishes grid connection corridors for efficient energy transmission, while ensuring compatibility with maritime navigation, national defence, and environmental protection.
Compared to the previous plan from last year, the FEP 2025 has cut the capacity of the N-9.5 and N-9.4 areas – the latter slated to be offered in a tender to be kicked off tomorrow – to 1GW each from 2GW previously envisaged.
The other amendment to the spatial plan carried out by the BSH is a division of an area further north that is slated to be tendered off later, previously called N-12.4, into two sites of about half the size, now called N-12.4 and N-12.5.
As a result of the reduced turbine density at the N-9.5 and N-9.4 sites the volume of this year’s offshore wind auctions goes down to 3.5GW from 4.5GW previously planned, a fact less welcomed by the industry.
Concerns over capacity cuts
“It is, however, a criticism that the capacity to be installed in this year’s auction will be reduced by one gigawatt one day before it starts,” Thimm said.
“The industry needs more planning security here.”
BWO also cautioned that in its medium-term outlook, planning security for investors has decreased as the latest spatial plan is less concrete regarding zones further from shore. The BSH now sets out an expansion path for 40GW of wind at sea by 2034, compared to 60GW by 2037 still detailed in the previous plan.
“This is a problem for the urgently needed ramp-up of the supply chain and makes investment decisions more difficult. It worsens the chances of more added value and jobs in Germany and Europe,” Thimm said.
“It is important that this outlook is expanded quickly and that the legal target of at least 70GW by 2045 remains stable across legislative periods.
“Anyone who thinks about installing fewer gigawatts is reducing the amount of clean and competitive electricity from the North and Baltic Seas that will be reliably available for the decarbonisation of the economy and society."
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