Should It Stay or Should It Go? The Tricky Issue of Old Offshore Platforms
A new survey of international experts has seen a swing of opinion away from mandatory removal of obsolete offshore infrastructure, reflecting an acknowledgment that offshore structures often develop into artificial reefs and form a part of the ecosystem around them.
A survey of international environmental experts suggests that attitudes to the decommissioning of offshore infrastructure, such as oil platforms, have shifted.
Almost 95% of the experts, drawn from 10 nations and across academia, government, and industry, say they believe that a more-flexible, case-by-case approach to equipment removal would be better for the environment.
Obsolete offshore infrastructure, including oil and gas platforms and wind turbines, must be removed in most regions of the world once they reach the end of their productive lives. Yet the practice has potential large-scale environmental impacts, including the loss of biodiversity and destruction of seabed habitat. More than 7,500 offshore oil and gas platforms in 53 countries will become obsolete in the next few decades, with eventual removal of rapidly growing wind turbine infrastructure a looming issue.
Although the study focuses on the North Sea, a current hot-spot of removal activity, the authors say the results have global implications given the distribution of offshore structures.
In contrast to current regulations, partial removal options were considered by the experts to deliver better environmental outcomes than complete removal for platforms; both approaches were equally supported for wind turbines.
Ash Fowler, fish ecologist and lead author of the study published in Frontiers in Ecology and the Environment, said that current removal policies are based on the assumption that “leaving the seabed as you found it” is the best way to minimize environmental impacts. These policies, however, do not take into account that, over their 20-30 year lifetime, offshore structures often develop into artificial reefs with high biodiversity and they come to form a part of the ecosystem around them on which a wide range of species may depend.
“These structures are huge, and removing them is complex and costly. Our findings indicate that here is a big gap between existing policy and current knowledge of decommissioning impacts,” he said.