It is key to the farms’ viability, avoiding expensive and slow redesigns as BP and rivals, try to build within the tight time-frames and budgets central to the success of the technology and their own balance sheets.
“You have to make sure you don’t have any schedule problems,” says Huw Traylor at consultancy DNV. “That’s a real issue: your installation schedule is based on the schedule for which you get paid.
“There are instances where developers have found things that have really knocked things back, such as bad geotechnical conditions.”
Wind turbines have become a feature of the British landscape in recent years, with more than 11,000 installed on shore and out to sea, generating around one quarter of Britain’s electricity over the year.
They are set to proliferate, with the UK Government pushing to increase offshore wind generation capacity five-fold by 2030 and Crown Estate Scotland auctioning off 7,000km-squared of seabed land this year to wind developers.
Energy giants – including BP’s rivals Shell and SSE – are jostling for space, and developing ever bigger turbines in the push for yield, with some rotor blades now longer than football fields and towers as tall as the Statue of Liberty.
“Offshore you’ve got a large area, you’ve got fewer objects and you can build at a really big scale,” adds Traylor. “That’s the driver.”
With such a big bet, BP needs to get the work on its wind farms right, dispatching fleets of small drone boats and larger crewed boats to gather soil samples and radar data as part of the extensive survey work to help it choose which foundations the turbines need and where they can be placed.
“It means we can plan correctly so we know exactly what’s going to happen when we come in with the installation vessels,” says Richard Haydock, BP’s project director for offshore wind.
So far, the company’s boats have spent more than 600 days out at sea this year and last. Teams of around 40 on crewed vessels work in 12-hour shifts, for up to 28 days at a time.
Among the crew are “marine mammal observers” and fishing industry representatives, to try to cut BP’s impact on wildlife and make sure it doesn’t interfere with fishing boats.
Some of the work is “really weather sensitive; we can only do it in about one-and-a-half meter seas,” adds Craig Allinson, a senior surveyor at BP. “It’s always really busy trying to keep the vessel operating as efficiently as we can, and safely swapping between the different modes.”