EAGER: Integrating efficient and dependable wave power generation into ocean sensing buoys: at-sea pilot tests.

Small oceanographic buoys enable a range of long-term in-situ measurements of ocean properties that are closely related to the earth's climate-related and other natural phenomena. Currently, such buoys rely on solar panels, wind turbines, and batteries for the energy they need for instrument operation. These researchers plan to conduct pilot tests to evaluate a new technique dependably to utilize ambient ocean waves to provide dramatically greater power amounts than existing sources. Dependable availability of larger power amounts to operate high-power instruments for long periods should be of interest the Ocean Science and Engineering communities. Additionally, the methods and data from this project are also expected to be transferable to small platforms designed for mid-ocean recharging of autonomous vehicles. <br/><br/>This research plans to test a new technique to control the wave energy conversion process such that the maximum practical power amounts can be converted in changing, irregular wave conditions. The team has learned through detailed hydrodynamic simulations and wave-tank testing that force and motion-constrained impedance matching control in realistic sea states can enable a 4-5 fold increase in the time-averaged power amounts that small oceanographic buoys might otherwise convert. With modest hardware additions, this improvement could allow standard oceanographic buoys to use wave energy as a power source. However, the proposed control requires real-time up-wave surface elevation measurements for deterministic wave-profile prediction 20-30 seconds into the future, and a bi-directional power take-off capable of providing large forces. To that end, the pilot study will use a fully-instrumented, currently operational wave-energy converter buoy with a bi-directional electro-hydraulic power take-off, to quantify the performance improvements possible (over baseline resistive control) with constrained optimal acausal real-time wave-by-wave control of the buoy oscillations. The team will use a high-resolution, short-range radar on-board the device to infer (up-wave) incoming wave fields for deterministic wave-profile prediction at the device. Results will enable an evaluation of the immediate merit of wave energy relative to other power sources available for ocean sensing buoys, such as solar, wind, fuel cells, batteries, and diesel generators.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.