Accusations of offshore wind theft hurled across North Sea
A top executive at Swedish power company Vattenfall has said wake losses sustained by German wind farms are pushing project power prices in Germany up well above those in other countries.
Wake loss refers to the reduction in energy output experienced by wind turbines due to the turbulence and lower wind speeds created by other turbines operating upwind of them.
The comments, made last week, come amid a year of escalating disputes over so-called ‘wind theft’ that has embroiled almost all of the biggest companies in North Sea wind.
In early May, Equinor and SSE alleged that wake losses caused by a planned RWE offshore wind project, Dogger Bank South, would cost their neighbouring farms US$778 million (A$1,205 mil) over their lifetime.
Cumulatively, around 20GW of projects in UK waters are embroiled in these kinds of disputes.
When a turbine is hit by wind it leaves a wake behind it, in the form of an area of lower windspeed, and therefore lower energy.
That means if another turbine - or another wind farm - is behind it, in the 'wind shadow', it will lose out on available wind energy.
And these wind shadows can extend up to 70 kilometres.
The problem will grow, with offshore wind farms predicted to take up almost 9% of the North Sea basin by 2050, or more than 60,000 square kilometres.
Addressing wake losses between separate farms requires geographically distancing them, or adjusting the power derived from the wind by one farm to enable another to get its fair share.
There’s also financial compensation, through a legal mechanism known as a wake loss agreement.