Wind measurement experts, gathered at a seminar hosted by Leosphere in June, claimed LiDAR is becoming the clear choice for bankable offshore wind measurements, saving millions on costs.
Major offshore wind energy players have shared their experience on a wide range of applications, from energy yield assessment to contractual power performance testing. Best practices in offshore LiDAR applications from different perspectives were presented at the seminar, with case studies from developers, OEMs and consultants.
“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,” said Anders Thoft Marcussen, Head of Measurements at DONG Energy.
LiDARs have been replacing met masts to become the sole wind measurement tool used for offshore resource assessment and power curve verification purposes, according to the experts at the seminar, who further stated that LiDAR technology had over the years fully proven its ability to provide wind measurements as reliably as met masts. They also claimed that LiDARs are faster, easier and much cheaper to deploy, enabling significant development and operational cost reductions.
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, Leosphere stated in a press release.
On the Beatrice Offshore Wind Farm 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. Beatrice Offshore Wind Farm Ltd (BOWL) chose instead to install two vertical profiler LiDARs which enabled them to start the measurement campaign much earlier and without the significant costs associated with installing an offshore met mast. After 12 months of LiDAR wind measurement the project had the essential data needed to help achieve financial close on the GBP 2.6 billion offshore project, Leosphere writes.
For an offshore project developed by RES, the installation of a met mast, estimated at EUR 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 adding millions of euros to the project value in addition to the millions in cost savings and the elimination of the health and safety risks associated with large met mast installation.
Presentations on LiDAR measurements were delivered by Klause Franke, Project Engineer at Deutsche WindGuard; Hans Verhoef, Project Leader Measurements at ECN; Cedric Dall’Ozo, Senior Wind Resource Assessment Engineer at EDF EN; Tue Hald, Senior Specialist at MHI Vestas; Iain Campbell, Technical Analyst and Wind Resource Manager at RES; Pedro Salvador, Rotor Performance Engineer at Siemens; Gordon Day, Offshore Wind Analyst at SSE; and Beatriz Canadillas, Senior Researcher at UL DEWI.
“LiDARs have become a reliable, robust measurement system that ultimately delivers the high-quality data to minimise uncertainty and risk while maximising value. 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. Today, LiDARs are commercially ready and already used in major projects around the world. It’s a trend that is going to continue both offshore and onshore, even in complex flow sites,” said Alexandre Sauvage, CEO of Leosphere.