A frozen wind turbine blade

Work Package 1: Icing

Leader: Tomas Wallenius, VTT

High-resolution meteorological and icing data from Iceland and Sweden and production data from large operational wind farms will be used to produce a detailed icing atlas for parts of Sweden and Iceland affected by icing. The icing atlas will serve as a basis for estimating icing risk and production losses due to icing, primarily as a selection tool for project feasibility and secondly, as a basis for development and selection of adapted technologies. An icing atlas is a prerequisite for a much needed, and long ago requested by the industry, market study of wind energy in cold climates.

Short term forecast of icing has to be an integrated part of the energy forecasts of future wind farms in the Nordic area. Icing due to in-cloud icing or rime over land as well as offshore icing of sea spray will affect the energy efficiency. Present weather prediction models include forecasts of the basic parameters for ice calculations (cloud water, humidity, temperature, wind speed etc), but the data are not very well understood with respect to wind energy applications. An optimal use of cloud and hydrometeor parameterisation schemes in the numerical models will be developed in the project.

An engineering tool/model to assess production losses from icing events is formulated. While there has been significant progress through the years in mitigating and avoiding the problem, forecasting icing conditions has only seen rudimentary attention. Likewise, there is no good estimate of the probable losses of large-scale wind power installations in the Nordic countries. Based on simulations of ice accretion on turbine blades for different icing conditions the general trends can be drawn to give the basis for the assessment of production losses. A rough estimate of the production losses together with icing event data is needed in the icing atlas.