NREL to make 2.0 version of wave-powered desalination device after first faced hiccups (Video)

Following months of data-driven insights from deployments off North Carolina’s Outer Banks, the U.S. National Renewable Energy Laboratory (NREL) is moving forward with a next-generation iteration of its hydraulic and electric reverse osmosis (HERO) wave energy converter (WEC), a wave-powered desalination system. 

During the deployment of NREL’s HERO WEC off North Carolina’s Outer Banks, severe storm conditions exposed a critical flaw in the system’s anchoring design. Monitoring equipment stopped transmitting data on pressure levels and energy output, prompting an inspection at Jennette’s Pier.

According to NREL, the device remained in place, but low-pressure readings from the reverse osmosis system indicated an issue. Divers from the Coastal Studies Institute (CSI) discovered that turbulent waves had caused the wire rope anchoring the WEC to twist around the water intake hose, and cut it.

This failure underscored the need for a more resilient anchoring solution. According to NREL, the new design phase builds on the team’s two-year in-water testing findings, aiming to boost the device’s reliability, deployability, and lifespan, which is important for regions with limited access to fresh water.

Anchored approximately 500 feet (152.4 meters) off Jennette’s Pier, the current HERO WEC’s initial deployment faced setbacks due to severe storms, which helped reveal improvements needed in its design. 

In response to equipment strain, the NREL team had mapped several upgrades to prevent anchor issues and maintain stability, drawing on the original design’s desalination performance despite challenging conditions.

According to NREL, upcoming refinements for HERO WEC 2.0 include an overhauled mooring system. The researchers are set to replace the stainless steel wire rope currently anchoring the device with a polyurethane flat belt, which they expect will resist wear and fatigue more effectively, extending the system’s operational lifespan in harsh marine environments.

“If that change is successful, it should help with a lot of these issues, making it a much more robust system,” explained Scott Jenne, Lead Marine Energy Systems Engineer on the HERO WEC project.

In addition to the mooring system, adjustments in device structure and components are under review to simplify deployment and increase efficiency. NREL’s team said it plans to downsize the hydraulic pump to reduce anchor loads and potentially reconfigure the WEC from an inflatable design to a rigid frame, which could streamline installation and provide easier access to control systems.

“We’ve been looking into downsizing the hydraulic pump to reduce anchor loads and potentially reduce the size of a transfer hose, which would further improve ease of installation,” said Justin Panzarella, a Full-Time Researcher who first joined the project as an intern. Panzarella added that structural changes, like adopting a more rigid frame, could make the device simpler to install, transport and maintain.

NREL said that it is also refining the HERO WEC’s data instrumentation, which initially adopted a “more is more” approach. The team intends to prioritize specific data, enhancing insights on energy production and water output for more efficient analysis and potential scalability.

“Instead of just looking at the data after the fact and saying ‘hey, we found this interesting thing,’ we can optimize what we want to collect,” noted Andrew Simms, an NREL Researcher focused on analyzing HERO WEC data.

The revised HERO WEC system will help set the stage for the U.S. Department of Energy’s (DOE) Water Power Technologies Office (WPTO) to set research goals and prioritize research funding. 

According to NREL, the team hopes to have the next version of HERO WEC designed, built, and ready to deploy by the summer of 2026.

Looking ahead, NREL said it envisions expanding the HERO WEC fleet nationwide, collecting broader datasets to support sustainable energy and water solutions across coastal and island communities.

“One of the major objectives of this project is not just to build the technology but to collect all the data—to share our learnings with others. And we can do that a lot more effectively if we can put more devices in the water at the same time,” Jenne said.

Back in March 2022, researchers from NREL deployed the HERO wave-powered desalination test device offshore North Carolina and anchored it to the nearby seabed, marking the start of ocean trials.