Background and Scope

As SODAR (SOnic Detection And Ranging) and LIDAR (LIght Detection And Ranging) technologies mature, more project developers are using these technologies to support wind resource assessments. These remote sensing instruments are relatively easy to use and move from site to site. They provide wind turbine hub-height wind speeds and direction, vertical wind speeds, and wind shear and veer above the heights of typical meteorological (met) tower measurements. They may also provide some measure of turbulence levels.

Unfortunately, users may fail to realize the full value of their remote sensing equipment due to a lack of clarity about best practices to ensure that their data will be useful for reducing uncertainty in future energy assessments. For example, the portability of remote sensing equipment has encouraged many users to measure for short periods at multiple locations in order to capitalize on their investment. Measurement periods that are too short, poor site conditions and a lack of verification of equipment performance can lead to data which are of limited or no use in an energy assessment.

This document provides guidelines on the use of remote sensing (Sodar and Lidar) measurements to support wind resource and energy assessments for wind energy projects. It includes guidelines for instruments on site, documentation and verification, and planning and implementing remote sensing measurements. The document also provides examples of their use. Instruments covered by this Recommended Practice include Sodar and Lidar systems intended to measure wind characteristics up to 200 m above the ground. Activities covered by this Recommended Practice include the collection of wind data for the purpose of wind resource assessments and wind project energy assessments. In this context, wind resource assessments are evaluations of the wind resource available at a wind energy project site and wind project energy assessments are evaluations of the energy generation potential of wind turbines planned for that project.

Purpose

This document describes DNV's guidelines for using remote sensing to gather data for wind resource and energy assessments.