Presentations

Abstract

The new DNV recommended practice "Lidar measured turbulence intensity for wind turbines" DNV-RP-0661 is presented. It provides a method to accept turbulence intensity (TI) data from ground based vertical profiling lidars (GBL). The recommended practice (RP) has been created because applicable standards in wind energy such as IEC 61400-13 currently relate to the use of TI measurements from cup or sonic anemometry only. Thus, they impede the application of GBL measured TI data. The RP can serve as a supporting document when considering the use of GBL TI measurements for the application of wind resource and wind turbine certification in combination with other applicable standards, recommended practices, and guidelines. The RP provides acceptance criteria for the use of GBL TI data. When the acceptance criteria are met, the lidar TI can be used as an alternative to cup or sonic anemometer TI data. The acceptance criteria employ error metrics which represent the deviation between lidar and co-located met mast TI (cup or sonic) measurement data in a meaningful way. The method is applicable to fixed offshore GBL and simple terrain onshore sites. TI measurements from GBL can be used quantitatively for use cases 'site suitability', 'load validation for type testing' and 'energy assessment' provided the GBL has fulfilled the acceptance criteria against a co-located met mast. The method proposed is technology agnostic and is intended to be applicable for all GBL models and types.