Industry consortium literature survey on Remote Sensing Devices confirms ZX 300 wind Lidar accuracy in all classes of complex terrain
The Consortium for the Advancement of Remote Sensing (CFARS) has presented a literature survey of Remote Sensing Devices operating in complex flow including the WindCube (Leosphere, a Vaisala company), Triton Sonic Wind Profiler (Vaisala) and ZX 300 (ZX Lidars).
CFARS is a wind energy industry consortium, composed of remote sensor and wind turbine OEMs, wind developers, academic researchers, and independent engineers, whose goal is to reduce cost and increase the safety of wind energy by broader acceptance and standardization of the use of remote sensing. ZX is a contributing member of CFARS, and co-author of the study in this article.
Ground-based Lidars and Sodars employ a variety of beam probing or scan patterns by which the horizontal wind speed, vertical wind speed and wind direction are derived – all assume homogeneous flow conditions within the scan / beam volume. In contrast, traditional meteorological masts equipped with cup anemometers provide a single measurement at the installation point of the sensor. In complex flow, often caused by terrain and fixed objects, the assumption of homogeneous flow conditions within the measurement volume introduces differences between lidar and cup anemometer. In situations like this a flow conversion technique can be applied.
CFARS have compared the various techniques adopted when using a WindCube, Triton and ZX 300 remote sensor and presented the following analysis of the accuracy of each device pre- and post-conversion / correction of data to account for the complex flow:
Across a broad range of cases previously published by ZX Lidars and Meteodyn incorporating 13 different wind project locations, data presented confirmed that CFD conversion of ZX 300 data in non-homogeneous flow conditions produced excellent agreement with collocated anemometry. As a result of this and other industry bodies of evidence, leading wind engineering organisations, and ZX Lidars, consider the data can be considered as finance-grade in situation.
With regards to the range of terrain classes as defined by [Bingöl et al., 2009][1]. ZX 300 was also shown to perform to high levels of accuracy in all conditions including even highly complex sites:
ZX 300 performance in complex flow is achieved by its unique 50 Line of Sight measurements in just 1-second. From this baseline performance, the use of additional Complex Flow tools available from a range of service providers including WindSim, Meteodyn and Natural Power are able to optimize the performance of ZX 300 further, delivering results that are traceable and auditable with a published conversion process.
Breaking News: ZX Lidars has continued to collaborate in this application. Following a successful development and validation programme by computational wind engineering company ZephyScience and independent wind consultancy Deutsche WindGuard, a further data conversion technique ‘ZX CFS’ (Complex Flow Solver) has now also demonstrated results to known and acceptable uncertainties allowing ZX Lidar systems to be deployed standalone in complex terrain and deliver wind speed and wind direction measurements that can be included within Energy Yield Assessments (EYAs) and Site Suitability Assessments (SA). Full details of ZX CFS are expected to be released in December 2020.
[1] F. Bingöl Complex Terrain and Wind Lidars. Risø-PhD-52 (EN) August 2009
Links and further information:
https://www.zxlidars.com/wind-lidars/zx-300/
http://www.cfars.org/
https://www.windguard.com/
https://www.zephy-science.com/
