Breaking wave

Wave to wire — a patented approach 

September 20, 2023 4:10 pm Published by

Five researchers cluster around a computer screen in a large shed-like building. They watch as a line moves up and down following the power output generated by the large, piston-like machine they designed to mimic the movement of ocean waves. Four hundred and fifty miles from the nearest ocean, a group of scientists at Sandia National Laboratories in Albuquerque, New Mexico have developed a method to help wave energy convertors (WECs) adapt their power output to account for different wave conditions.

Sandia National Laboratories water power engineers Giorgio Bacelli, left, Dave Patterson, center, and Ryan Coe with Sandia’s wave energy converter buoy. Photo by Randy Montoya.

Marine energy is a rapidly growing industry with the potential to power remote coastal and island communities, replace diesel ship engines, and increase the security and sustainability of our energy grid. However, placing a WEC in the ocean comes with a lot of risk and uncertainty. The WEC might not produce enough energy over its lifespan to make it cost effective to deploy.

Sandia researchers recently received a patent (US 11,703,027 B1) for developing a controller that maximizes electrical power generation and power absorption by allowing a WEC’s power take-off, the device that converts motion to electrical energy, to automatically adjust to different wave types. More predictable power flow from “wave to wire” allows the controller to improve WEC performance. More accurate performance estimations and increased output reduces costs and uncertainty, two major barriers to large-scale deployment of marine energy grids.

The water power researchers considered a wide range of complex and cutting-edge algorithms and found that a relatively simple control approach provided improved WEC performance, especially as the power contained in ocean waves tends to vary slowly, changing over the course of hours. This, according to Ryan Coe, one of the researchers who helped develop the controller, “allows the patented tuning approach to be so effective.” The controller was designed and tested by a multi-disciplinary team consisting of Giorgio Bacelli, David Wilson, Dominic Forbush, Steven Spencer, and Coe. A “simple is best” approach led to the development of the patent-worthy controller, a device that has the potential to reduce some of the risks associated with WEC deployment. The research was funded by the U.S. Department of Energy’s Water Power Technologies Office.