Daylight considerations for offshore wind operations and maintenance

The cost associated with operations and maintenance (O&M) for offshore wind is a cost that developers and operators are striving to reduce in order to reduce the overall Levelised Cost of Energy. Improving accessibility and increasing time based availability of wind turbines can guarantee these reductions. To increase time based availability, some wind farms utilise night shift work to reduce downtime for turbines. Previous studies revealed cost reductions using this method but are strictly based on North Sea wind farms. This paper investigates the impact daylight hours have on the O&M costs for an offshore wind farm depending on location. Using an O&M model, three maintenance strategies are simulated and their associated O&M costs are found: ‘Daylight Limited’, ‘Daylight Not Limited’ and ‘Night Shift’. Three case studies are chosen: North Sea, USA and Australia. The operational costs for the North Sea were reduced by £32.74/MWhr with the introduction of the night shift. With increased daylight, the US site saw a smaller reduction in operational costs of £3.48/MWhr using the night shift. However, the Australian site was negatively impacted when adopting a night shift strategy as operational costs increased by £3.19/MWhr. The study considers, if there are reductions in cost through night shift, is it worth the trade-off the industry makes for health and safety of technicians who work at night.