11/21/2022 William Gillespie
Dream team to design optimal ocean wave energy generator
Written by William Gillespie
Wave Energy is renewable energy derived from oscillation of ocean waves. Like wind or solar energy, wave energy does not produce carbon emissions or greenhouse gases, and uses natural resources already in abundance.
Designing generators powered by wave energy may even have some similarities to designing for other sources of renewable energy — such as the need to provide steady output from a generator subject to the whims of the weather — but the engineering challenges for capturing wave energy are largely unique, even compared to hydro-kinetic energy derived from currents that move in a single direction, such as turbines in dams. Although techniques have been developed throughout history to design structures exposed to ocean waves, such as bridges or ships, established techniques may not apply to engineering a device meant not to resist or divert the power of waves, but instead to capture it.
Over time, the power of waves turns boulders to sand, and salt water is corrosive even at rest. How does one design a turbine that can convert the explosive, corrosive, and unpredictable oscillations of the ocean into a smooth flow of electricity?
When these challenges are overcome, wave energy has very attractive potential. According to Brittanica.com, "estimates of the annual wave energy potential along the continental shelf of the U.S. coasts range between 1,170 and 2,640 terrawatt-hours, equivalent to 33–65 percent of U.S. electricity demand in 2015." The total annual potential of wave power is estimated to be 3.7 terawatts, almost double current world energy consumption.
It's also the case that other renewable energy sources, such as wind and solar, have reached maximum capacity in some regions, underscoring the need for alternative sources. Wave energy has been shown to be non-redundant with wind and solar, making it a nice addition to a clean energy portfolio.
Designing technology for sustained wave energy collection is a challenge that has proven too daunting for investors, but the greatest minds in the world are now being brought in. Professor James Allison has been tapped by world wave energy expert Professor John Ringwood of Maynooth University, Ireland, to be part of SeaChange: an elite, international consortium of investigators tasked with designing wave energy systems that maximize the Levelised Cost of Energy (LCoE) of wave energy, which can be thought of as cost over kilowatt hours, calculated over the lifetime of the project.
The project is called SeaChange, a name that does not understate the potential importance of this renewable energy technology. It is a five-year, $860,000 project funded by Science Foundation Ireland, starting December 2022. SeaChange will employ four new Ph.D. students and one senior post-doc.
Collaborators include Dr. Jorgen Hals Todalshaug, CorPower Ocean, Sweden; Dr. Jochem Weber, National Renewable Energy Laboratory, USA; Professor Mogens Blanke, Technical University of Denmark; and ISE's Professor James Allison.
Professor Allison has worked on ocean-based wind turbines — another unique engineering challenge in renewable energy — as well as river turbines, and is a leading proponent of the "control co-design" methodology. Control co-design is a revolutionary systems design philosophy that has emerged in the past two decades. Previously, the interface between application technologists and control engineers has been sequential: application specialists design the fundamental system dynamics, with the system then passed to the control engineers for control design. Control co-design allows the engineers creating the control system to participate fully in overall design to optimize the positioning of the control system and its relation to other systems in the design.
ISE applauds the investigators of SeaChange in their efforts to “catch a wave” and harness the wild energy of ocean currents to create a more orderly, sustainable energy system.