Posters

Abstract

At risk of sounding like a stuck record... pre-construction Energy Yield Assessments (EYAs) are still overestimating operational performance. This is despite many good validation exercises showing how the gap has narrowed, or been eliminated, between pre-construction and operational EYA estimates. So, what is going wrong? Can things be improved? Or am I just unfortunate in my experiences? A detailed review of over a dozen operational assets has highlighted some big discrepancies and a clear bias. Statistically, the bias in the results cannot be by chance. Instead, issues have been identified that demonstrate overestimation of the energy yield. For some aspects, correction of these issues could be achieved through better asset management, for example items related to availability. Others were outside the scope of the original EYA, for example future wakes from neighbouring wind farms or grid curtailments. However, some aspects need to be addressed directly in the pre-construction analysis, for example regarding resource overestimation, internal wakes and turbine performance losses. This presentation highlights the delta between pre-construction EYAs and operational performance, the financial impact this has, and the actions taken to resolve this issue. Two immediate practical solutions implemented to address both the risk and gap are explained: an EYA checklist to identify high risk projects, and a corresponding performance optimization process to increase operational generation. Additionally, some longer-term initiatives are suggested to provide a lasting solution. Principally, use of open-data and automated analysis to provide data driven validations, use of structured EYA data to better compare results, and collaboration in developing and validating pre-construction EYA tools.