Advancements in Offshore Wind Lidar Measurement Campaign from the Global Blockage Experiment (GloBE)
Channel: NSF NCAR Research Applications Laboratory
Date: 2024-01-19

Scanning Doppler wind lidars offer an immense deal of flexibility in their configuration and operation. These instruments are rapidly growing in use within wind energy for both commercial and research focused applications. 

The Global Blockage Experiment (GloBE project) has recently conducted one of the world’s most extensive offshore wind measurement campaigns, with the aim of measuring wind-farm scale blockage using three pairs of dual-Doppler scanning lidars along with a substantial number of other supporting measurements. All measurements are subject to sources of bias and uncertainty and managing these is a key challenge- both while planning and conducting the measurements, and when analyzing and making conclusions from the gathered data. 

This seminar will report on the activities conducted by DTU within GloBE towards investigating sources of bias and uncertainty and the resulting methods developed for mitigating them. The main sources to contend with are effects which lead to the incorrect pointing of the lidar’s laser beam. This primarily originates from the motion of the offshore wind turbine's transition piece where the equipment in installed and is driven by the turbine operation, sea state, and foundation design. Pointing errors are also contributed from device levelling errors, motor homing offsets, and backlash in the scan head mechanics. A comprehensive scope of work within GloBE was dedicated to understanding the impact of these error sources towards the goal of producing a top-quality dataset to allow for identifying wind-farm blockage. 

This work provides a comprehensive examination of the sources of bias and uncertainty in offshore scanning lidar measurements and develops a set of practical strategies for mitigating those issues. The material presented will be particularly useful for those interested in achieving the lowest uncertainties in their own offshore measurement campaigns using the latest developments and innovations. More generally, it will convey just how difficult measuring the wind can be!