DEVELOPMENT OF A COST EFFECTIVE, VARIABLE DEPTH, TIDAL AND RIVER CURRENT MEASUREMENT BUOY.

Marine hydrokinetic energy technologies are approaching commercialization. However, one barrier to development is finding cost effective methods of conducting resource assessments, or easily measuring current speed and direction in high velocity tidal and river environments. Incumbent technologies for tidal energy resource assessment are typically variants of acoustic Doppler current profilers (ADCPs), but they are expensive to operate and there is risk to the equipment in high current locations. Research and development was therefore undertaken to design, build, and test a variable depth, long endurance, and cost-effective means of measuring tidal and river water current velocities. In conjunction with Mavi Innovations, the University of British Columbia developed a prototype two-point mooring sensor, which can be deployed in river or tidal environments over sustained periods in order to gather both water velocity and current direction data. The sensor was successfully deployed over two periods of approximately 24 hours during both a spring and neap tide at Mavi's tidal energy demonstration site at Blind Channel, British Columbia. Results of the deployments provided ample current speed and direction data to inform turbine developers of the tidal current regime at the site, and also offered some agreement with ADCP measurements done simultaneously. Test results broadly demonstrated good potential for the technology, particularly for smaller or remote projects where the cost or logistics of ADCP deployments are less feasible and where quickly accessible data are needed, without too much pre-deployment calibration or post-deployment formatting time. Operational challenges still remain for the buoy sensor, and various options for further development and testing are suggested in this paper, along with detailed discussion of the trial deployments, sensor design, construction, and calibration methods. [ABSTRACT FROM AUTHOR]