Sponsored by the Water Power Technologies Office and directed by the Pacific Ocean Energy Trust, TEAMER offers developers and researchers the opportunity to test and refine their marine energy technologies at a range of facilities in the TEAMER Network.
TEAMER’s support allowed the University of Hawai’i to advance two oscillating water column technologies. An OWC is a type of wave energy converter that harnesses energy from waves. It uses the power of waves, funneled into an open chamber, to pressurize air. That pressurized air then spins a turbine and generates electricity.
Drawing Inspiration from Nature
UH first tested an OWC designed to support autonomous underwater vehicle (AUV) docking and charging capabilities. The device, known as Project Hālona, was based on a prominent coastal feature on the island of Oahu known as the Hālona blowhole. The blowhole has unique geologic properties and takes incoming waves and magnifies them through a hollow chamber into a geyser.
“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,” says Nicholas Ulm, UH PhD student and founder and CEO of Hawai’i Ocean Power Solutions LLC.
“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,” he explains.
Project Hālona is designed to power ocean observation platforms or AUVs that support various ocean observation applications such as collecting data to monitor and predict hurricanes. The AUVs this device is designed to support will be equipped with sensor equipment to measure ocean characteristics like current velocity and temperature that can be uploaded to Hālona.
Many wave energy devices emphasize extracting the most amount of power from the ocean to generate electricity for power grids, but in the case of ocean observation applications, the priority becomes how much power is needed to charge ocean observation platforms or AUVs. Consequently, Hālona was designed to minimize motion and maximize stability to enhance AUV docking while still providing adequate power to enable charging.
Powering Scientific Exploration through Wave Energy
Much of Hālona’s design and testing would have been impossible without TEAMER. The project began with numerical modeling and testing at UH’s Applied Research Laboratory, but when testing in a larger wave basin became necessary, TEAMER was able to support the team with access to Oregon State University’s (OSU) wave basin. There, UH was able to test how a 1:10 scale model of Hālona would perform in multiple wind and wave conditions. A later round of TEAMER support enabled researchers to conduct a 1:4 scale model test at Texas A&M’s Offshore Technology Research Center’s wave basin, where the team looked at the geometry, weight, and mooring options for the device in a way that would have been impossible at UH.
The ability to charge AUVs generated interest from the U.S. Navy’s Naval Facilities Engineering Command, which provided additional non-TEAMER funding to the UH team and will provide access to open water test locations, such as the Wave Energy Test Site (WETS) in Hawai'i. WETS is the United States’ first grid-connected wave energy test site that helps companies test pre-commercial technologies in the water to advance their technological readiness level.
The growing success of this project led Ulm to take Hālona from a technology concept for his dissertation and launch his own company, HOPS. Most recently, Ulm led a TEAMER proposal with HOPS for modeling support from the American Bureau of Shipping (ABS) to test whether an updated Hālona design could recreate the previous TEAMER test results numerically.
“TEAMER has been absolutely critical to my dissertation and my career success,” said Ulm. “TEAMER has provided us with opportunity to demonstrate how wave energy can scale and given us access to high quality research and facilities.”
Looking Toward the Future
The team behind Hālona is now looking toward its next steps, including working with ABS again to review previous work for a new technology qualification that could help the team move closer toward commercialization.
UH is also looking to collaborate with HOPS to build a larger Hālona prototype for ocean testing in Hawai'i. This prototype will be integrated with an experimental power take-off system. Once successfully tested, the power take-off system will also be used
