Origami-inspired flexible wave energy device undergoes testing at NREL

At the National Renewable Energy Laboratory (NREL) Flatirons Campus, researchers have embarked on testing a flexible wave energy converter (WEC) prototype, designed to advance the capabilities of marine renewable energy. 

The collaboration between NREL, the University of Florida, and the U.S. Department of Energy (DOE) resulted in a prototype built under the distributed embedded energy converter technologies (DEEC-Tec) project, recently trialed at NREL’s Sea Wave Environmental Lab.

Suspended by a crane, the flexWEC was lowered into a 13,000-gallon testing tank before its underwater movement was illuminated by LED strips and recorded using advanced visual diagnostic systems, NREL noted. 

Ph.D. student Isabel Hess spearheaded the motion-tracking effort, gathering deformation data for performance optimization. “Perturb means ‘change,’ and the device’s equilibrium is its upright position,” Hess explained. 

“When waves push the device out of this position, my cameras capture the device’s deformations, or movements. This visual data will help us assess the device’s performance under different wave conditions, which will guide us in optimizing future versions.”

Supported by the DOE’s Marine Energy Graduate Student Research Program, Hess collaborates with her professor, Patrick Musgrave, and NREL Senior Engineer Blake Boren to refine the origami-inspired flexWEC design.

According to NREL, DEEC-Tec technology represents a departure from conventional WECs, which rely on rigid structures and concentrated surface areas to capture ocean energy. The flexWEC incorporates distributed energy converters, enabling it to bend and flex like seagrass to harness energy from a wider range of wave conditions.

“When you have a lot of force concentrated on a specific WEC surface area, it’s more likely to fail,” Musgrave noted. “With DEEC-Tec, you have many points throughout the structure, flexing, bending, harvesting, and converting ocean wave energy. The prototype we’re testing today is one of many first steps toward that type of device.”

The design’s flexibility improves durability and facilitates transport and deployment by allowing the device to fold itself during storms or for easier storage, NREL noted. 

Hess’ work with motion-tracking and computer vision tools is providing insights into how DEEC-Tec structures deform under various conditions, laying the groundwork for the technology’s broader adoption.

“Currently, there is no off-the-shelf solution for characterizing underwater deformations for DEEC-Tec-based ocean wave energy converter concepts,” Boren explained.

“Isabel’s research in motion tracking and computer vision helps fill this gap by allowing us to measure these underwater deformations and will be hugely impactful for designing, analyzing, and optimizing efficient, DEEC-Tec-based ocean wave energy converters such as origami flexible WECs.”

The collaboration is also exploring hydraulically amplified self-healing electrostatics (HASELs) as a new type of energy converter for marine applications. 

According to NREL, HASELs are designed to convert external mechanical forces into electricity without relying on traditional materials like metals and magnets, potentially lowering production costs and enabling more adaptable designs.

“This approach could provide a continuous flexible structure and also make it more adaptable to a broader range of ocean wave frequencies and periods,” Hess said.

To refine the concept, Hess is characterizing the performance of individual HASELs, investigating their efficiency and potential integration into larger WEC systems.

“We’ve determined that HASELs are more efficient at converting external mechanical forces into electricity than we initially anticipated,” Boren said. “This tells us that they are worth further research to enhance their efficiency as energy converters.” 

The project highlights the importance of partnerships in advancing marine renewable energy. Hess’ fellowship experience has allowed her to gain practical expertise while contributing to important research.

As the research continues, the team aims to further refine DEEC-Tec devices and explore new applications for HASELs in wave energy systems.

“DEEC-Tec broadens our community with new perspectives, technological domains, and materials we’ve never used in ocean wave energy before,” Boren said. “It really does represent an opportunity to be more innovative in how we think about ocean wave energy.”

The DEEC-Tec project is funded by the DOE Water Power Technologies Office (WPTO). Applications for the 2025 Marine Energy Fellowship are open through December 6, 2024.

In September, the U.S. DOE’s WPTO issued a $112.5 million funding call to spur the demonstration of wave energy technologies through open water testing and system validation.