The International Electrotechnical Commission (IEC) has published a new standard, IEC 61400-12-1:2017, formally allowing LiDARs as a supplementary or alternative measurement technique to mast-mounted cup anemometers.
The release of the new standard is considered a major milestone in LiDARs’ growing maturity, ZephIR Lidar stated, as the guidance now recognises the imperfect relationship between cup anemometers at hub height and full swept area of the turbine.
The new guidance introduces the concept of “Rotor Equivalent Wind Speed” (REWS), which considers the impact of wind shear and wind veer on turbine power performance. This is especially relevant for ever-larger blade lengths and hub heights, according to ZephIR Lidar.
The guide also covers resource assessment measurements for forecasting annual energy production, following the increased use of LiDARs by the wind industry offshore and onshore.
There is an increasing number of offshore wind farms that have opted out of using tall masts and are instead deploying Continuous Wave (CW) LiDARs, as well as onshore sites all over the world moving to LiDARs for all stages of development and operation, the company said.
Ian Locker , Managing Director, ZephIR Lidar stated: “When we set out to create our first CW lidar over 15 years ago, we always hoped that our systems would play a role in changing the stance on wind measurements and masts in the wind energy industry. We very much look forward to the future and seeing how the wind industry will further expand on the use of wind lidar.”
Although the new IEC standard does not cover nacelle-mounted LiDARs, the ZephIR DM nacelle-mounted product has the capability of outputting a REWS-compliant set of measurements, the company pointed out.