Analysis of derating and anti-icing strategies for wind turbines in cold climates

Wind turbines located in cold climates suffer from reduced power generation due to ice accretion. This paper presents a novel method for comparing and evaluating two emerging ice mitigation strategies: tip-speed ratio derating and electrothermal anti-icing. The method used takes into account accumulated ice mass, net energy losses both during and after an icing event, and financial breakeven points; it is demonstrated for the assessment of the NREL 5 MW reference wind turbine during different icing events. Our results show how derating can be preferred over electrothermal anti-icing and how this changes for different wind speeds, icing conditions, ambient temperatures, and system costs. For a 1-hour extreme icing event, it is expected that derating will reduce accumulated ice mass and daily power loss by up to 23% and 37%, respectively. Anti-icing was identified to be the preferred strategy when there were 42 in-cloud icing event occurrences per year, ambient temperatures were above −5 °C, and the system cost was no higher than 2% of the turbine’s capital cost. This research demonstrates to wind turbine operators how different strategies can be selected to improve performance during icing conditions.