This paper presents a new method of online wind turbine performance modelling (recursive parameter estimation) that addresses the nonlinearity associated with wind turbine performance characteristics. A sliding linearization algorithm is implemented to track changes in the turbine operating environment. A multivariate polynomial approximation of the turbine power coefficient is developed to produce a linear process model approximating the operating wind turbine. The estimated model parameters are recursively calculated to compensate for changes in both the turbine operating environment and the condition of the wind turbine. The algorithm models both the steady-state and dynamic wind turbine performance throughout the entire operating range, producing a continuously valid turbine linearization with applications in gain scheduling and turbine performance optimization. Copyright (C) 2016 John Wiley & Sons, Ltd.