ZephIR Lidar notes that its turbine-mounted Dual Mode (DM) system has been deployed by developer Renewable Energy Systems Ltd. (RES) in a commercial investigation into LIDAR-generated turbine performance measurements.
The trial, which began in June and is expected to end this month, uses a ZephIR DM installed on a Vestas V90 turbine. ZephIR says its DM is capable of measuring upwind and providing absolute (traceable to IEC Standard 61400-12-1CD) and relative power curve assessments.
In non-complex terrain, the company explains, current industry guidelines require measuring the wind at distances of two to four rotor diameters upwind – minimizing blade induction effects on the wind speed.
Complex terrain causes the wind model to evolve as it moves over the landscape approaching the turbine, meaning that the wind and available energy at the turbine rotor can differ significantly from the measurement point, the company adds.
To combat this uncertainty, ZephIR says wind speed can be measured much closer to the turbine. Although these measurements are within the blade induction zone, the company says their repeatability is higher and will be less influenced by the complex terrain. The ZephIR DM and ZephIR 300 LIDAR systems can measure at distances as short as 10 meters and out to 300 meters.
With the ZephIR measuring at 135, 90, 45 and 10 meter ranges in its second phase, the trial exploits the DM's ability to measure short distances upwind of the turbine within complex terrain to produce power curves, according to ZephIR.
"Traditional methodologies for measuring power curves have practical and technical challenges," says a spokesperson for RES. "This trial has the potential to change current methodologies, address existing challenges and improve commercial relationships between developers, operators and turbine suppliers by better understanding the relationship between wind and turbine performance."