Vaisala and DNV have introduced guidelines for utilising scanning lidars in a dual system configuration (DSL) for offshore Wind Resource Assessment (WRA). The publication of these guidelines aims to enhance the bankability of dual scanning lidars and contributes to the development of the International Energy Agency (IEA) Task 52 recommended practice on employing scanning lidar measurements offshore.
Dual scanning lidar is increasingly replacing meteorological masts for offshore wind park developments near the shore (up to 15 km), allowing offshore wind project developers to reduce extrapolation uncertainties and obtain a more comprehensive understanding of the wind resource in the planning areas. DSL can remotely measure wind speed and direction at multiple offshore locations from the shore. The collaborative document outlines the various phases of a typical DSL campaign for wind resource assessment:
- Campaign planning.
- Lidar pre-campaign verification.
- Installation and commissioning.
- Operation and monitoring of the specific measurement campaign.
- Data processing.
- Uncertainty evaluation.
- Decommissioning and post-campaign verification.
The Dual Scanning Lidar Principle section elucidates the mathematics behind reconstructing horizontal wind speed and direction from two line-of-sight wind speed measurements. It discusses factors influencing uncertainty such as beam geometry, mode of operation, scan parameters, and environmental conditions. The document also underscores proper setup, alignment checks, performance monitoring, data collection, and maintenance procedures, and offers proprietary methods to calculate uncertainties of intermediate and final reconstructed values.
