The UK’s offshore wind industry will need to lean on oil and gas expertise to help decommission wind farms as more than 3 gigawatts (GW) of offshore wind power reaches the end of its design life by 2034, an industry decommissioning conference heard in November.
The cost of removing the installed base, as at 2017, could be about £4 billion, says John Warrender, chief executive of industry membership group Decom North Sea, told the Offshore Decommissioning Conference in St Andrews, Scotland.
What’s more, by 2030, if goals to install more than 30GW of offshore wind power by 2030 are met, the prize for decommissioning the UK’s installed offshore wind base could be in excess of £10 billion, he told the conference.
“Offshore wind decommissioning is going to ramp up very quickly,” Axel Laval, Asset Manager, The Crown Estate, said, speaking at the same event. The first two UK wind turbines, at Blyth, in England, have already been removed. By 2034, close to 3GW of power will reach the end of its design life, Laval says. That amounts to 1000 turbines to be removed.
However, just as offshore oil and gas decommissioning costs have been riddled with uncertainty (although that’s now improving), offshore wind decommissioning costs currently vary hugely. The challenge for offshore wind is that this creates uncertainty around the cost of energy for ongoing and future wind farms, says Laval. “It’s difficult to lower the cost of energy if you don’t know the cost of removing it,” he says.
Estimates are about £80,000-300,000 per megawatt (MW), he says. The total liability, for the installed base as at 2017, has been estimated at £1.82 billion. Given the wide range of cost estimates per megawatt, that means – to decommission the installed base as at 2017 – the numbers could be between £1.28-£3.64 billion range, he says.
Laval says there are currently 2,225 turbines installed in the UK North Sea amounting to 9,953MW of offshore wind. If the goal to reach 30GW of offshore wind power in the UK by 2030 is met, there could be some 5,000 turbines.
That amounts to about 200,000 metric tons of composites, mostly in the blades, that will need to go to landfill at the end of its life. In addition, there would be 1.3 metric tons of steel in the foundations and towers, 100,000 metric tons of copper in the export and array cables, and 50,000 metric tons of lead in export cables, said Laval.
With 30GW installed, there would be some 600,000 metric tons of composites to be removed at the end of life, 5 million metric tons of steel and 300,000 metric tons of copper. While the composites would cost £60 million to land fill, the steel and copper would recover scrap value at about £1.05 million each.
Here, there are opportunities, especially around recycling all that steel, says Laval. Recycled steel versus virgin steel production would see a 74% energy saving, he says. For aluminum there’s a 95% saving. Some 1.5 metric tons of iron ore is needed to produce every metric ton of virgin steel, he points out, as well as 0.5-tonne of coke. In the process of producing virgin steel, a lot of CO2 emissions are also emitted – which could be reduced by 86% by recycling steel instead.
“There’s no sense reinventing the wheel,” adds Laval. “The industry that is closest to what we (in offshore wind) do is oil and gas. So we need a supply chain from oil and gas to help (offshore wind) operators reduce the cost of offshore wind decommissioning.”
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