Low cost load monitoring for offshore wind farms

Operation and maintenance (O&M) costs for an offshore wind farm are currently very high; the relative contribution of O&M to the kWh price can amount to 25-30%. ECN is currently developing the LoadWizard, which is a methodology which enables low cost load monitoring for an entire offshore wind farm. For this, two main aspects need to be considered. First, a reliable system for measuring the mechanical loads needs to be used, which can survive in the harsh offshore conditions without the need for regular calibration and maintenance visits. For this purpose ECN has developed the patented FOBM sensor assembly based on optic fibres. Second, ECN has developed the Fleet Leader concept, which is a methodology with which the load measurements on only a few 'reference' turbines can be used to accurately predict the mechanical loads on all other turbines in an offshore wind farm. With this information one can monitor the actual loading and possibly optimise and reduce the cost of O&M.