PO027

Scanning LiDAR in Offshore Wind - how far can it go?

Michael Stephenson 4, Keith Barr3, Lee Cameron1, Alex Clerc1, Peter Stuart1, Matthieu Boquet1, Loic Merillion2
1RES, Kings Langley, UK, 2Leosphere, Paris, France, 3Lockheed Martin, Colarado, USA, 4Carbon Trust, London, UK

Abstract

Scanning LIDAR is not a new technology – it has been used in a variety of ways for decades – however it is only relatively recently that it has been used in offshore wind. While there is broad acceptance across the industry that the technology could be very useful, it is not yet clear how to maximise the benefit of this innovative technology in offshore wind. To address this challenge, the Offshore Wind Accelerator programme launched the world's largest offshore trial of scanning LIDAR systems in January 2016. This presentation will show the ground-breaking results from the trial and discuss the consequences of these results on the industry.

Method

The Offshore Wind Accelerator has carried out a four month trial of two pairs of scanning LiDAR devices. These devices were installed in Dublin Bay and validated against two vertical profiling LiDARs to determine their accuracy and precision. The devices were set up to measure wind speeds in a nominal offshore wind farm within the bay, which stretched to over 10km from the devices at its furthest point. Each device was to measure wind speeds at a range of heights at eight set points offshore and validated against fixed vertical LiDAR. The system suppliers were left to devise their own scanning patterns and algorithms to process the data, and the trial was carried out completely blind with validation by RES as an independent third party.

Results

The results show phenomenal accuracy at ranges never tested before in offshore wind (>13km). Results of both single and dual Doppler will be shown, which demonstrate that whilst single Doppler will need further work to be viable for offshore wind, dual Doppler has given very convincing results for both manufacturers.

The results will also show the effect of deploying scanning LiDAR on a potential annual energy production, with uncertainty of the P90/P50 ratio being brought down by between 1-2%.

Conclusions

The main conclusion of the trial is that scanning LiDAR can work for offshore wind and can produce very accurate wind speed measurements at very long ranges. There is further work to be done in order to improve some of the algorithms of the devices themselves but for certain sites this technology can have real cost reduction benefits.

Scanning LiDAR is the latest in a long-line of innovations within the field of energy yield assessments but potentially one of the most exciting for some time.

Objectives

Delegates will learn about the operational capability of a range of scanning lidar devices offshore. the presentation will discuss practical lessons and considerations, data capture and analysis and potential future applications that delegates will be able to apply directly to their own projects.