Posters

Abstract

More than a decade ago the Carbon Trust published the first version of the OWA Roadmap for the Commercial Acceptance of Floating LiDAR Technology. Since then, the use of floating lidar systems (FLS) evolved significantly, being now the industry's standard measurement tool for offshore wind resources assessment. The continuous development of the technology raises questions about the validity of original guidelines. In 2020 a group of FLS experts took on the task and started to develop the IEC 61400-50-4 (IEC 50-4), which provides guidance on the use of FLS and introduces some evolved methods for deriving measurement uncertainties. The standard is currently available as Committee Draft (CD) version and will be published in 2024/2025. As per IEC 50-4, the measurement uncertainty of a FLS is described as follows: u_FLS2 = u_cal2+u_cal2+u_con2 u_cal = calibration uncertainty u_cla = classification uncertainty u_con = configuration uncertainty Whereas calibration and classification uncertainties are calculated following a well described procedure, the assessment of the configuration uncertainty (summarizes uncertainties associated to the reproducibility of the configuration and measurement setup of a FLS deployment) is not firmly defined and is more dependent on the judgement of the analyst who is doing the assessment. This study investigates different methods for assessing configuration uncertainties. It comprises data sets from four FLS (two types) which have been deployed at two different project sites in the UK. All systems have gone through pre- and post-calibration campaigns against Blyth offshore met mast which provides a measure for the consistency of FLS performance over time and are used as a benchmark for other methods investigated. The study presents suitable alternatives for assessing FLS performance over time, resulting in reduced configuration uncertainties in the magnitude of 0.5 % to 1.0 %. At the same time, these methods are providing some economic advantages.