PNNL

Abstract

Autonomous surface vehicles (ASVs) are small sensor-laden watercraft that are used to collect environmental data in coastal and marine locations. Their operation is constrained by energy storage limits, but with adequate resources, marine energy presents an opportunity to provide power in remote locations. To demonstrate the feasibility of using tidal energy to support ASV operations, we created a MATLAB-Simulink modeling tool. The model simulates an ASV performing surveys and charging at a nearby tidal turbine. Model components include tidal turbine, generator, battery storage dynamics, ASV kinetics, and ASV control code blocks. We refined the tool using experimentally collected data in the tidal-resource-rich Sequim Bay to empirically identify vehicle hydrodynamic drag and inertial coefficients. We then used the model to simulate a resource characterization survey in Sequim Bay under varying environmental conditions and survey parameters. Results indicated that a tidal turbine can support continuous ASV operation in low tidal or low target survey speed scenarios, and we suggest improvements to the model.