Scanning LiDAR Trials Start off Ireland

The Carbon Trust has today started the world’s largest trial of scanning Light Detection and Ranging (LiDAR) technology in Dublin Bay, Ireland, the latest Offshore Wind Accelerator (OWA) project designed to help reduce the cost of energy from offshore wind.

Over the next three months, four different scanning LiDAR systems will be put through their paces, alongside three vertical profiling LiDARs for validation purposes. The project is being supported by independent renewable energy company, RES, and maritime safety organisation, Commissioners of Irish Lights.

The units involved in the trial are three Leosphere WINDCUBE vertical profiling LiDARs, one Leosphere WINDCUBE 400S scanning LiDAR, one Leosphere prototype scanning LiDAR, and two Lockheed Martin WindTracer scanning LiDARs.

Scanning LiDAR technology has already been used by the defence and aerospace industries to monitor for oncoming weather fronts, but it does not have a proven track record in offshore wind.

Normally wind resource is measured using met masts which require a large capital investment (GBP 10-GBP 12m) incurred at risk before a project gets the go ahead, adding significant upfront costs which could inhibit the exploration of new sites. The OWA project aims to test how accurately scanning LiDAR technology can measure wind resource for potential wind farm sites, which could deliver significant cost savings in the early stages of wind farm development.

The OWA has been working for the past few years to support more cost effective solutions, focusing on the development and commercialisation of a number of floating LiDAR systems to reduce upfront capital expenditure. Yet measurements taken by both masts and floating LiDAR are limited in that they only provide a measurement of the wind resource at a single point in space. For an offshore wind farm covering an area of up to 200 square kilometres, this can create uncertainty on the wind speed at locations far from the measurement point. This is known as spatial variation, where measurements may not representative of the entire site. This is translated into risk incurring additional financing costs to wind farm development.

Scanning LiDAR technology has the potential to reduce the risk associated with spatial variation. These systems are capable of scanning with a usable range of between 10 to 30 kilometres, taking over 100 measurements per minute. This allows developers to build a much more detailed picture of a site, not only reducing uncertainty of spatial variation, but also allowing developers to better plan the layouts of the turbines to best exploit the individual wind conditions at the site. Increasing confidence on spatial variation could reduce risk to minimal levels, which can save millions of pounds on a project and reduce the cost of energy from offshore wind, The Carbon Trust says.

A difference of only 0.2 mph in wind speed can result in significant variation of yield calculations over the lifetime of a wind farm. It is therefore critical that the industry has confidence in scanning LiDAR devices being sensitive enough to detect such small variations. The OWA trial aims to test the sensitivity of the devices to picking up these variations in wind resource.

“Many factors can impact available wind resource at a potential wind farm site including its proximity to shore, neighbouring wind farms, and as a result of tidal currents,” Megan Smith, Project Manager, Wakes Research at the Carbon Trust, said.

”This project forms a really important stage of the OWA’s efforts to increase the industry’s understanding of wind resource measurement and validate the technologies capable of delivering results. Project financing is a significant proportion of cost, so anything we can do to get a deeper understanding of yield will increase investor confidence and lower the cost of financing. Scanning LIDAR has the potential to take our understanding to a completely new level. In information terms it is the difference between taking a still photo compared to having a three dimensional video with full sound. The need to test the sensitivity of the technology is the next frontier in getting industry acceptance.”

Photos: The Carbon Trust