Practical Approaches to Performance Warranties for Wind Turbine Blade Heating Systems

Abstract

As de-icing and anti-icing blade heating systems for wind turbines continue to mature, operators have developed a clearer understanding of both their benefits and their limitations. This growing operational experience has increased the need for warranty frameworks that can verify whether such systems perform as intended under real icing conditions. This study builds upon existing approaches to blade heating system warranties and, based on case studies, proposes practical methods to improve them. The principal challenge lies in separating meteorological risk, namely the frequency and severity of icing events, from technological risk, namely the availability and effectiveness of the blade heating system. This paper provides an extensive review of existing approaches to blade heating system warranties and proposes a practical self-comparison methodology for evaluating turbine-level performance using measured operational data. The method defines the applicable warranty period from external icing measurements, excludes periods of active meteorological icing to reduce the influence of site-specific exposure, and evaluates the remaining production shortfall using the Warranted Icing Compensable Energy, WICE. The methodology is applied to five case studies from four wind farms, four turbine manufacturers, and four blade heating technologies. The proposed framework provides a transparent and operationally applicable bridge between existing warranty guidelines and the detailed implementation rules required for commercially meaningful performance assessment of wind turbine blade heating systems.