At a seminar hosted by Leosphere at the Offshore Wind Conference 2017, wind measurement professionals explained that years of successful LiDAR validation campaigns and strong competitiveness have led industry players to choose this technology over met masts for offshore wind feasibility studies as well as power curve verification tests.
“Experience has taught us that the uncertainty levels offered by LiDARs are at least on par with those offered by met masts. Although we still encounter performance misconceptions surrounding LiDAR technology, it is now hopefully a mere question of time before the industry as a whole recognizes this technology, and IEC standards are adapted accordingly,” explained Anders Thoft Marcussen, Head of Measurements at DONG Energy.
In practice, the use of nacelle mounted LiDARs is already frequently required in the turbine supply agreement for power curve verification testing, even if LiDAR measurements are not yet covered by IEC standards.
Met masts cannot compete with LiDARs on cost in the offshore market. On the Beatrice Offshore Wind Farm Ltd (BOWL) project, a 588MW 84 turbine offshore wind farm off the North East coast of Scotland, the wind measurement campaign was carried out without the use of a met mast. BOWL chose instead to install two vertical profiler LiDARs. After 12 months of LiDAR wind measurement the project had the essential data needed to help achieve financial close on this £2.6 billion offshore project.
For an offshore project developed by RES, the installation of a met mast, estimated at €12 million, was ruled out in favour of a single fixed LiDAR, coupled with two floating LiDARs. The fixed LiDAR, installed on a nearby lighthouse, and the floating LiDARs located at points across the wind farm zone, enabled the company to secure reliable, bankable data.
"The prevailing view among experts is that the future of resource assessment is short masts coupled with LiDAR for onshore, and for offshore probably just the LiDAR", concluded Alexandre Sauvage, CEO of Leosphere.
