Inside Out: Floating LiDAR Systems

December 21, 2015

Originally published in The Journal of Ocean Technology, Vol. 10, No. 4, 2015

http://www.thejot.net

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The offshore wind industry continues to grow as the benefits become better understood and technological advances help to reduce the overall cost of development, making it more efficient and cost competitive. In 2014, 1,713 megawatts of new offshore capacity was added, bringing the total to 8,759 megawatts.

The key benefits of offshore wind include:
• Stronger wind speeds available offshore compared to on land brings a higher contribution of electricity supplied.
• Most of the world’s largest cities are located near a coastline.
• Offshore construction makes sense in densely populated coastal regions with high property values.

Initial wind resource assessment is a critical first step to offshore wind development, and the single most important characteristic of a site is its wind speed. The performance of a wind farm is very sensitive to uncertainties and errors in the basic wind speed estimate; therefore, the assessment must be extremely accurate in order to secure funding and for the economic development of a wind farm. The traditional solution to measuring local wind conditions is to construct a rather costly (CDN$14.2m) and time-consuming (one year) meteorological mast equipped with anemometers and extrapolate those measurements across the length of the wind farm. To measure sea states, wave buoys and weather forecasting models are used.

The AXYS Floating LiDAR system eliminates the need to construct a meteorological mast and provides all the required data from a moveable and low environmental-impact buoy. The Floating LiDAR system is a wind resource assessment buoy capable of accurately gathering data on wind speed and wind direction offshore at turbine hub-height and across the blade span. As the system name indicates, the primary sensor on the system is a LiDAR that works on the principle of bouncing lasers off air particles and reading the resulting Doppler shift in order to assess wind speed and direction. The system is available as a 4-metre polyethelyne buoy hull or as a 6-metre steel NOMAD buoy hull, coupled with a single or dual LiDAR
configuration capable of measuring wind up to 200 m. The AXYS Floating LiDAR system was also designed to accommodate a variety of metocean sensors and telemetries that provide weather and sea state data to greatly enhance data from forecasting models.

The collected wind data enables developers to understand how strong the winds are at the heights of wind turbines, provides a clear picture of how much power can be generated at specific sites, and helps to validate wind predictions from computer models. Meteorological and ocean measurements also help scientists understand air-sea interactions.
The Floating LiDAR system facilitates cost effective, accurate monitoring of many key parameters required by offshore wind farm developers to determine if their proposed project will pass financial investment decision and gain the financial support needed from their project funders. AXYS is committed to the industry objective of reducing the cost of offshore wind development and estimates that using Floating LiDAR systems will reduce the cost per MWh by CDN$0.45 by 2025.

 

Copyright Journal of Ocean Technology 2015