On October 12, an H135 and an H145, from KN Helicopters and HTM Helicopters respectively, hoisted cargo and two crew members onto the nacelles of floating wind turbines and in the rough autumn conditions (30 knots of wind and sea state 6) they'd set out to test. The day before, they lifted cargo onto the nacelle in almost 50 knots of wind and sea state 6.
In late 2022, Equinor agreed to hold the trials in Hywind Tampen, a floating wind farm already producing electricity to nearby platforms.
The logistics involved a special permit (Air Operator Certificates) from the Norwegian aviation authority, safety audits, risk assessments and standard operation procedures (SOP), in addition to extensive briefings for all crew members. Having highly experienced flight crews was a must. HTM and KN Helicopters, of Germany and Denmark respectively, both leading providers of helicopter hoist services for the offshore wind industry loaned their pilots for the test flights.
“We've been hoisting to bottom-fixed offshore turbines for many years,” said Alain Vigneau, Head of Offshore Wind Market at Airbus Helicopters, regarding Airbus helicopter missions to offshore wind farms. “Now we want to demonstrate a helicopter's capability in connection to floating turbines.”
And on that blustery day, they would do just that. Even in the North Sea's five and a half meter-high waves, conditions were challenging but feasible.
With wind farms moving further from land, the rush is on to install these 250-meter-high floating structures on supports moored to the seabed. Hywind Tampen is a unique set-up using 11 wind turbines 110 NM from shore to generate electricity to power its oil and gas platforms.
“The conditions were at the upper limit of what is possible but we proved we could position the technicians on the turbine in a safe and efficient way,” said Bernd Brucherseifer, Managing Director and Pilot at HTM.
With 12 GoPro cameras on the helicopters, an H135 from KN Helicopters hoisted a cargo onto a nacelle atop turbine N o 2. Next, an H145 from HTM hoisted two passengers onto the nacelle of turbine N o 2.
"Today we showed we could hoist from floating turbines even in high sea states,” said Martin Knudson, Chief Pilot at KN Helicopters.
"The helicopter is the only reasonable means to deploy personnel in this sea state,” says Christopher Brons-Illing, Senior Engineer Operations at Equinor, one of the trial’s organizers and part of the hoist team. “I’d definitely do it again.”
It all adds up to less downtime for the turbines and more active use of technicians’ time – and quite possibly – a sprightlier technician at the end of the trip.
Footage from the cameras, plus motion data from the turbines, is now being analyzed and will be shared with the industry to mature standard operating procedures for hoisting to floating turbines. A collective effort that augurs well for this emerging technology for renewable energy production.