Fixed offshore accommodation will be instrumental in resolving the operations and maintenance (O&M) dilemma faced by operators of wind farms installed far from shores, according to a report commissioned by Fred. Olsen Windcarrier.
Reducing transit time and improving turbine accessibility are two key issues for operators, and the study by Norwegian simulation experts Shoreline found that a combination of a fixed accommodation platform and fast in-field vessels will help solve both.
The analysis used MAINSYSTM software and complex modelling to simulate three O&M scenarios with different marine logistics combinations for a UK-based wind farm with more than 70 turbines and located 100 kilometres from the nearest port.
The three base scenarios were: a single service operation vessel (SOV) with on-board accommodation; two platform supply vessels (PSVs) and an offshore accommodation platform such as Fred. Olsen Windbase, and three crew transfer vessels (CTVs) and an offshore accommodation platform. All three scenarios included the use of a helicopter for troubleshooting and additional crew transfer vessels over the summer period.
Fred. Olsen Windcarrier UK General Manager, David Matthews, said: “All three scenarios performed with relatively high time based results, but the best availability – nearly 98% – was with the scenario employing three CTVs combined with an offshore accommodation platform,” Matthews said.
“The main difference was that the scenarios relying on the vessels equipped with walk-to-work access system had less availability when the overall workload was increased because of their low in-park speed in dynamic positioning mode and higher reliance on helicopter support.”
“Of course different sites and scenarios could be used, and we would recommend to simulate and keep simulating to really test the robustness of any given solution,” Matthews said. “But for this study what was very clear, particularly as the number of unscheduled failures rose, was that fixed offshore solutions, specifically the Fred. Olsen Windbase, have the potential to be industry game changers.”