Drifters as preliminary site assessment tool for ocean current-based renewable energy for straits and channels in the Philippines

We study the possibility of using ocean surface drifting buoys (“drifters”) as a low-cost alternative to assess the potential of a tidal channel to deliver useful renewable energy. Instead of using Acoustic Doppler Current Profilers (ADCP) for underwater ocean current measurement, we propose the use of drifters released on localized areas of interest which is more affordable and flexible for use of coastal communities in the Philippines. We discuss the drifters used in our experiments and show our methodology with field results obtained from an actual drifter deployment on April 2010 in the Mactan-Olango Channel of Cebu, and in Ligpo island, Anilao, Batangas, Philippines. Since power extraction devices and systems used for tidal currents primarily take into account flow speed in the channel, we present flow speed data derived from the Mactan-Olango and Ligpo drifter deployments. We also discuss how this effort can be refined and replicated to yield site assessment guidelines including power prediction estimation using drifter data.