RWE Innogy, in partnership with the operator of Eneco Luchterduinen offshore wind farm, has successfully completed the trial of an innovative offshore buoy for measuring wind and wave data in the Netherlands. The floating measuring platform demonstrably fulfilled the requirements with regard to availability and accuracy. For the purpose of testing further technical configurations with various manufacturers, an additional floating LiDAR was installed off the Dutch coast mid-March. The research project’s objective is to develop a cost-effective alternative to fixed met masts. Floating LiDAR systems are expected to only cost 10 to 20 percent of a conventional measuring mast, indicating huge potential to make a considerable contribution to cutting development costs of offshore wind farms.
The newly launched trial is part of the world’s largest validation trials of floating LiDAR, that were recently commenced by the Offshore Wind Accelerator (a research initiative from the UK Carbon Trust involving the major offshore wind farm operators). The first trial conducted in 2014 was supported by the research and development programme FLOW (Far and Large Offshore Wind), funded by the Dutch Ministry of Economic Affairs.
“By testing different floating LiDAR units we help to increase the confidence in this innovative technology and to reduce cost for offshore wind parks in the long-term”, said project manager Niels Bijkersma from RWE Innogy. “At the same time we allow individual manufacturers to work towards the commercial acceptance of their buoys while gaining some valuable hands-on experience for our own projects.”
First trials in the Netherlands completed
In 2014, RWE Innogy and Eneco jointly tested the floating measuring platform manufactured by Fugro OCEANOR, which was installed some 75 kilometres off IJmuiden in the Dutch North Sea, in the immediate vicinity of an offshore met mast operated by RWE Innogy. Unlike traditional offshore met masts, the floating platform uses a so-called “LiDAR“ (Light Detection And Ranging) system, a laser-based technology for remote measuring of wind speed and direction. The buoy performed measurements for more than six months, which were subsequently analysed by an independent company and compared with those of the fixed met mast. Due to its location and high availability the latter was found to be very suitable for wind and wave measurements. Lasse Lønseth, project manager at Fugro OCEANOR said: “The tests demonstrated the very high accuracy in the wind profile measurements from the buoy based LiDAR compared to the accurate mast based sensors. The test also provided important experience with operation of the LiDAR buoy in harsh North Sea conditions.“
It is planned to deploy the measuring buoy at the development site of wind farm Navitus Bay, a 50-50 Joint Venture between Eneco and EDF Energy, at the English South Coast. Ruben Dijkstra, Director of the Offshore Wind division at Eneco added: “The test results were compelling. It is the first time that we will receive wind and wave data from a mobile measuring buoy during the development and construction of our wind farm. This will make us more flexible and cut costs.”
New trials started
RWE Innogy’s decision to install an additional metocean buoy at the beginning of February 2015 follows on from the results of previous tests. The buoy manufactured by EOLOS mainly differs from the technology tested in 2014 in terms of dimension, power supply and the mooring system: “The EOLOS Buoy is a fully autonomous and all-in-one system which can accurately measure wind, wave and current. It has been designed to minimize both CAPEX and OPEX of offshore wind measurement campaigns. Its purposely designed structural skeleton and mooring system provides the necessary robustness to withstand the rough environment of the North Sea, while at the same time reducing the weight of the system”, summarizes Rajai Aghabi, CEO at EOLOS Floating Lidar Solutions, the buoy features. An independent data analyst will analyse data on wind speed and direction for over six months.
R&D in focus
RWE Innogy invests some 4.5 million euros annually in applied research. Testing innovative measuring methods for offshore wind applications is one example of the company’s research activity. As part of the initiative, two tests have already been conducted in the UK in addition to the trial in the Netherlands.