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More cable failures at European and UK offshore wind farms

Global Warming Policy Forum

Lower wind speeds and cable problems hit first-quarter earnings at Denmark’s Orsted, sending shares in the world’s biggest offshore wind farm developer lower on Thursday.

General view of the Walney Extension offshore wind farm operated by Orsted off the coast of Blackpool

The Danish offshore wind giant, Ørsted, has released its Interim Financial Report for the first quarter of 2021, and has revealed that up to ten of their European and UK wind farms are suffering from significant damage to connection cables. Repairs are currently estimated to cost in the region of 3 billion Danish Kroner (£350m) over the period 2021 to 2023.

The problem has arisen because turbines are frequently surrounded with large rocks designed to prevent erosion of the seabed and weakening of the turbine foundations. This “scour protection” is, in Ørsted’s own words, “abrading the Cable Protection System and in the worst-case scenario causing the cables to fail.”

As a listed company, Ørsted is under strict reporting requirements to keep the markets informed of problems affecting their business. This has led them to be one of the first to reveal specific details of problems affecting much of the sector, and it is likely that the cable problem they report affects other companies.

In one sense, though, the announcement is no surprise. As long ago as 2019 industry press sources were reporting that 90% of European wind farms had experienced significant problems with their cable connections, with one article in reNews in 2019 reporting that “a growing chorus of voices is blaming the relentless drive to force down costs”. Whether this is the case for Ørsted we cannot say, but investors will doubtless be asking precisely this question.

Dr John Constable, GWPF Energy Editor, said:

Ørsted’s announcement should lead analysts to ask, firstly, whether claimed reductions in offshore wind capex are a reality once adjusted for quality, and secondly, whether any real reductions in capex have been offset, or more than offset, by increases in opex.”


1. Ørsted’s Interim Financial Report is available here

2. GWPF has repeatedly raised questions over the underlying economics of offshore wind (, and published trailblazing work on capital cost by Gordon Hughes, Capell Aris and John Constable ( Subsequently Professor Hughes has published a major analysis of the data with the Renewable Energy Foundation ( in which details of rising operation costs are given.