The IWR performance check uses the output data of the operating wind station to predict future earnings. Wind station financing companies, banks, developers and private investors have commissioned individual wind station checks to find out the real long-term average performance of an operating wind station and what variations are to be expected, says IWR. "They can then find out whether and to what extent the expected actual average annual performance coincides with the wind assessment forecast produced before the station was built. That way, real wind station project controlling is possible."
IWR's wind performance check is based on "a standardised scientific method to calculate the long term 100% output level of a wind station using a long term, 30 year base period," says the company. The check reveals the 30 year average annual energy output of the station, the percentage annual deviation in output from the long term average, the average monthly output and size of deviations, and calculates the probability of a wind plant achieving a specific annual performance. This provides the baseline for the operator to secure business with financial hedging, says IWR.