Q&A with Yi Chao: How Seatrec’s technology is turning the ocean’s thermal energy into electricity

In the realm of renewable energy, solar and wind may get the lion’s share of media attention and industry buzz — but when we were introduced to the remarkable technology developed at Seatrec, we knew the company was onto something game changing. Founded by Dr. Yi Chao, this fascinating renewable energy company has developed a unique solution that generates electricity from temperature differences in the environment. We recently asked Yi to tell us the story behind the Thermal Recharging (TREC) Battery technology and give us a glimpse of Seatrec’s plans for the year ahead.

From left to right: Yi Chao (Founder and CEO); Jack Jones, Scott Leland, Robin Willis (engineers); Dave Fratantoni (CSO).

Breakout Labs: For people who aren’t familiar with the TREC battery, can tell us a bit about how you developed your energy harvesting technology with the team at JPL?
Yi Chao: Over 95% of the ocean is completely unexplored because ocean’s hostile and complex environment makes manned platforms extremely costly to operate underwater. After working 20 years at NASA’s Jet Propulsion Laboratory (JPL) developing satellite technologies to observe ocean from space, I realized that Unmanned Underwater Vehicles (UUVs) are the only scalable and cost effective ways to explore the 3D ocean.

Today’s UUVs are powered by single-use batteries with limited capacity and lifespan. To overcome this problem, I assembled a team of engineers at JPL to develop a recharging battery that can extract energy from temperature differences in the ocean. Starting from an internal seed grant of $30K for a three-month design study, we obtained a three-year internal grant of $300K to refine the design and mature the technology. Follow-up funding of $3M from DoD Office of Naval Research over the next three years allowed us to develop a prototype and successfully demonstrated that our Thermal RECharging (TREC) battery can provide 10x more energy than the single-use lithium batteries in UUVs today.

Seatrec's Thermal Recharging Battery for Underwater Instrumentations

BOL: How does it convert thermal energy to electrical energy?
YC: We convert thermal energy to electricity whenever there is a temperature difference (e.g., between the surface and the deep ocean) or change (e.g., between day and night). We harvest the thermal energy by using phase change materials that exhibit substantial expansion during a solid-to-liquid phase transition. The high pressure created by the expansion is used to drive an electric generator and the resulting energy is stored in rechargeable batteries.

BOL: What eventually inspired you to leave JPL to commercialize TREC for the oceanographic community?
YC: After the TREC prototype successfully completed an 18-month endurance test in the ocean, I felt it was ready for commercial development. Companies I contacted initially were hesitant to license the TREC technology because of risks involved in the commercialization effort. I, however, felt confident about TREC’s potential to change the way we explore the ocean.

BOL: Which industries are showing the most interest in this kind of technology?
YC: We are focusing initially on the UUV industry. UUVs require a source of electrical power for propulsion, navigation, data collection, and communications, which is typically supplied by single-use batteries. Harvesting the thermal energy associated with temperature differences in the ocean is the only scalable and cost effective way to power UUVs with unlimited capacity and endurance.

BOL: What advantage does the TREC battery offer other forms of renewable energy?
YC: The TREC battery is unique because it harnesses renewable energy in the ocean’s interior. Other forms of renewable energy (e.g. wind, solar, and wave) are all at the ocean surface. It can be challenging and costly, however, to transfer energy from the ocean surface to the interior, and it may be impractical for certain UUVs to regularly surface because of security considerations.

BOL: What are the current and potential future applications for TREC?
YC: The primary current application for TREC is to replace single-use lithium batteries currently used to power Argo floats, a collection of 4000 floats worldwide to monitor the ocean’s role in climate change. Every year, 800 new floats have to be deployed to replace those floats that stop working after the battery dies. The TREC battery would significantly increase the lifespan of the Argo floats, enable floats to collect data more frequently than every ten days established by the international Argo community in order to conserve energy, and to carry more power-demanding sensors that are not currently feasible (e.g., chemical, biological, acoustic, and optical).

Beyond the floats, the TREC battery can increase the endurance and capability of underwater gliders and create an ocean power station that could generate electricity to recharge propeller-driven Autonomous Underwater Vehicles (AUVs) or operate an underwater communication hub.

BOL: What are your long-term plans for the company?
YC: Within the next five years, Seatrec would like to have a significant presence in the underwater float market, leveraging our team’s extensive experience in the oceanographic community. While raising Series A round, we are actively seeking industrial partnerships with companies whose UUV programs can directly benefit from the TREC technology. We are looking for federal R&D funding opportunities (e.g., DoD, DARPA) to further mature the TREC battery for underwater gliders and power stations. We will also explore applications of the TREC technology in the Arctic and terrestrial environments.


To learn more about the TREC battery and follow the progress of Dr. Yi Chao’s team, visit the Seatrec.com.

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