HSE
Faced with the looming prospect of rows of crumbling turbines, legislators are belatedly starting to reflect on what can be done. In the first place, their problems are made much worse by a lack of research. Beyond some honourable exceptions, there is a concerning lack of knowledge over what removing turbines will do to the local marine environment – environments, remember, that were already altered when the turbines were first installed.
One solution, it appears, could involve renovating ageing turbines to give them a second lease of life. Another – though perhaps ironic for an industry built on sustainability – could be learning from how the oil and gas sector has approached decommissioning. There are even some suggestions that, for the good of the planet, old turbines are left as they are, providing shelter to underwater creatures even as their energy-producing days are done.
All for nothing? It’s hard to overstate how quickly the problem of offshore decommissioning is going to increase. Consider the numbers. In principle, offshore machines should function properly for between 20–25 years, though worn-down components can sometimes hasten that estimate. We must also factor in the wealth of turbine construction we’ve seen over recent decades – despite the challenging economic conditions, Europe still installed 4% more turbines in 2022 than the year before, equivalent to 19GW of new installed wind capacity, even as the Global Wind Energy Council estimates that climate goals require the construction of four times the current number each year. With this in mind, it’s not hard to see why Dr Antony Knights says that turbine decommissioning is going to become “a pretty big problem” over the years ahead. That’s especially true, explains the associate professor in marine ecology at the University of Plymouth, in places like the North Sea. The UK may have been ahead of the game when it came to exploiting wind energy, but that equally means it’ll be among the first countries to deal with what comes next.
This looming crisis is hardly helped by the fact that the sector has struggled to plan ahead. In part, this is an issue of research. Beyond a couple of exceptions, notably in Northern Europe and the Gulf of Mexico, scientists have failed to fully consider what decommissioning would mean for the natural environment offshore turbines leave behind. At the same time, however, scientists and other stakeholders can build up a body of evidence based on another offshore industry, albeit one not traditionally associated with the green transition. “Although decommissioning in the wind energy industry differs from that in the oil and gas and
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nuclear sectors, eventual decommissioning of offshore wind turbines will involve environmental considerations similar to those of other man-made structures,” explains Dr Michaela Schratzberger, science director at the Centre for Environment, Fisheries and Aquaculture Science (CEFAS), a government body that works with scientists and other stakeholders to build the evidence base in support of decommissioning decisions. Yet, if they can offer plenty of pointers – including the need to design structures in a way that make them easy to dismantle, as well as the importance of securing the skills of decommissioning experts – oil and gas installations also pose challenges for turbines. Fundamentally, this is a question of regulation, in particular a rule called OSPAR 98/3. Applying across the north-east Atlantic, involving 15 regional governments and encompassing both wind turbines and petroleum installations, it requires what the regulation describes as the ‘complete removal’ of most man-made structures from the sea.
90%
The percentage of 40 industry experts surveyed in 2018 that said that governments should abandon the principle that offshore structures should always be removed.
University of Technology, Sydney, Australia
“Although decommissioning in the wind energy industry differs from that in the oil and gas and nuclear sectors, eventual decommissioning of offshore wind turbines will involve environmental considerations similar to those of other man-made structures.”
Dr Michaela Schratzberger Balancing acts
That might sound fine in theory. Why, after all, wouldn’t you want to return the marine environment to a pristine condition – especially in a sector predicated on sustainability like wind? In practice, however, such draconian rules may actually not be the best way forward. Put it like this: the moment a turbine’s installed, the local environment is transformed already, and not necessary for the worse. Sea snails, algae and marine plants are all drawn to the turbines, notes Knights, explaining that some turbines mimic the ecosystems of rocky shores. From there, he continues, seabirds can find a home among offshore structures, as can certain species of fish. This point is supported by the numbers: researchers in Germany have found that a typical offshore turbine can support up to four tonnes of shellfish, a bounty that’s sure to attract crabs and fish, themselves the natural prey of seals. And while there are certainly downsides to transforming the sea in this way – the fact that invasive species can also be drawn to human-made
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