TAccording to the Water Power Technologies Office (WPTO), TEAMER has facilitated testing and refinement for two oscillating water column (OWC) technologies, enabling UH to push the boundaries of wave-powered solutions for ocean observation and shoreline protection.
An OWC is a type of wave energy converter (WEC) that harnesses energy from waves. It uses the power of waves, funneled into an open chamber, to pressurize the air. That pressurized air then spins a turbine and generates electricity.
Advancing AUV docking with project Hālona
The first UH-tested OWC project, known as Project Hālona, is designed to support autonomous underwater vehicle (AUV) docking and charging. Drawing inspiration from Oahu’s Hālona blowhole, the device employs a vertical “straw” mechanism where internal water reverberations create pressure to spin a turbine and generate electricity, noted WPTO.
“Think of the core of the device being a straw floating vertically in water. The internal water surface in the straw reverberates because of how the wave is restricted at the bottom opening,” said Nicholas Ulm, UH PhD Student and Founder of Hawaii Ocean Power Solutions (HOPS).
“It’s similar to the effect you get when you roll down a window on the highway and hear the reverberation in your ear. If you constrain any wave into a chamber of a certain size, you will cause a resonant pressure. We are trying to induce that resonant effect, but in our case, we’re using the water surface inside a straw as a kind of piston to compress air through a turbine system above the water.”
Hālona aims to power ocean observation platforms and AUVs with sensors for measuring ocean characteristics like current velocity and temperature. Unlike traditional wave energy devices focused on maximum power generation, Hālona is said to prioritize stability and efficiency to enable reliable AUV docking and charging.
TEAMER’s support enabled UH to test scaled models of Hālona at leading facilities, including Oregon State University’s wave basin and Texas A&M’s Offshore Technology Research Center. These tests evaluated the device’s performance in various wave conditions, geometry, and mooring configurations, WPTO noted.
The project’s potential attracted interest from the U.S. Navy, which provided additional funding and access to the Wave Energy Test Site (WETS) in Hawaii.
“TEAMER has provided us with opportunity to demonstrate how wave energy can scale and given us access to high quality research and facilities,” added Ulm.
Integrating wave energy into coastal protection
According to WPTO, the second OWC project focuses on developing a breakwater system that integrates wave energy extraction.
This curtain pile breakwater design is said to reduce construction costs while promoting environmental benefits by allowing water and marine life to flow naturally between the harbor and the ocean. The system incorporates OWC chambers to generate power while mitigating coastal erosion and storm surges.
“If we’re building breakwaters in the world due to sea level rise and coastal mitigation needs, why not integrate wave energy extraction into such a structure?” asked Patrick Cross, Director of the Hawaii Marine Energy Center.
“And why not integrate OWC modules into it for power extraction?”
Preliminary tests in small wave flumes at UH laid the groundwork for larger-scale testing supported by TEAMER. The team plans to test ten one-meter-wide OWC chambers at Oregon State’s wave basin in early 2025. Using orifice plates to simulate energy conversion mechanisms, these tests are said to evaluate the breakwater’s functionality and power production capabilities.
Scaling up for the future
Looking ahead, UH aims to collaborate with HOPS on building a larger Hālona prototype for ocean testing in Hawaii, integrated with an experimental power take-off system. According to WPTO, this advancement could also inform the development of the OWC breakwater system, bringing the technology closer to commercialization.
“TEAMER has been an outstanding augment to other sources of funding for larger-scale testing,” Cross added.
“The team at Oregon State has outstanding professionals with extensive experience in marine energy testing and are great to work with. One of the stars of the TEAMER network.”
In early January, TEAMER approved 15 marine energy projects and allocated nearly $1.9 million through its fourteenth request for technical support (RFTS). According to TEAMER, technical expertise and access to facilities will be provided, enabling recipients to advance testing, modeling, and innovation for marine energy technologies.
