Windfarms and radar, various judgement processes

The Netherlands Organisation for Applied Scientific Research TNO is regularly tasked to perform windfarm-radar impact studies. The requests most often come from windfarm operators in Europe, but studies for an operator based in Australia have also been performed. Referring to terminology introduced by Eurocontrol’s wind-turbine task force (WTTF), both simple engineering assessments (SEAs) and detailed engineering assessments (DEAs) are conducted. Certain civilian or military ANSPs (air navigation service providers) do, however, not follow Eurocontrol’s guideline, in which case a DEA is conducted, regardless of the distance between the radar system and the windfarm. The analyses may involve both primary and secondary radar systems. The main ingredients of TNO assessments are briefly sketched. Subsequently, the judgement process, i.e., the criterion upon which the verdict on windfarm construction is based, is discussed. It is observed that ANSP’s do not always utilize a well-defined criterion, which gives rise to subjectivity