- Keywords: Wind resource measurements
This new approach assesses onshore and offshore wind potential remotely. Especially for offshore wind potential assessments, with the sensor remaining on the coast, this offers clear cost benefits compared to the installation of expensive offshore platforms and masts.
The two-month performance verification of the two WINDCUBE 400S LiDARs installed side-by-side was carried out by DNV GL and results were compared to those from a high-quality reference met mast. Reconstructed wind speed and direction (HWS and HWD) measurements for each of the LiDARs used individually, and based on averaged horizontal readings at 10-minute intervals from the Scanning LiDARs’ Plan Position Indicator (PPI) scans, were compared to IEC compliant cup wind speeds and vane wind directions read from a conventional mast anemometer at the top of a 100-metre mast.
LiDARs exhibit a good resemblance to reference wind measurements
Scanning LiDARs operated with a range resolution of 200 metres at a distance of approximately 1.8 kilometres from the reference mast, using a beam elevation angle of 3 degrees, and targeting the top mounted anemometers of the mast at 100 metres above ground. The results were compelling: the mean wind speed absolute error observed between the SLD and the met mast reference was less than 0.3 metres per second for a wind speed range of 2 to 13 metres per second. The wind direction measurements compare very well with the mast’s vane measurements with a mean direction error of less than 2 degrees. In essence, the wind data from both Scanning LiDARs showed a good resemblance to the reference wind data, indicating consistent behaviour between the two individual units.
“This relatively new LiDAR technology has proven to be a highly efficient and time/cost-effective alternative to high quality conventional met mast anemometry, and is clearly ready for the market,” said Detlef Stein, Global Head of Practice for Resource Measurements at DNV GL. “At our testing facility in Janneby, which we have been operating together with two expert partners since 2013, we and our technology partner Leosphere were able to show that this applies to onshore wind resource assessments, and more importantly, to the remote measurement of data for offshore wind resource assessment. This is a milestone in remote wind speed measuring.”
“This external validation proves the ability of our scanning LiDAR to accurately reconstruct the wind at multiple points up to a few kilometres – in this test two kilometres – using a single system, which can successfully support a wind resource assessment programme,” commented David Langohr, Product Marketing Manager at Leosphere. “This is substantial evidence of our system’s good performance in offshore wind applications. It underpins the maturity and acceptance of our technology for operational use and confirms Leophere’s leading position in LiDAR technology.”
DNV GL wind turbine and remote sensing testing facility
The wind turbine and remote sensing test site was developed by experts at DNV GL, site owner Bürgerwindpark Janneby e. G., and GEO Gesellschaft für Energie und Ökologie mbH; it is located in Janneby in northern Germany. Manufacturers who use the test field will be able to take advantage of the full range of DNV GL’s independent services.
The executive summary of the LiDAR performance verification report, can be downloaded here.