23 | Cullen Quine — Postdoctoral Researcher at NREL & Co-founder of Activated Energy

🐝 What is >100X more energy dense (33 kWh/kg) than Li-ion batteries (0.3kW/kg), and why is it so hard to store it at room temperature? What is a naturally-occurring gas that can be uniquely compressed into a non-toxic, non-flammable liquid at room temperature? And, how is beekeeping like energy storage cleantech?! To answer these questions, we're joined by Cullen Quine. He provides insights on his team's work, both as a Postdoctoral Researcher at the National Renewable Energy Laboratory (NREL) and as Co-Founder of Activated Energy (unaffiliated with NREL), in conversation with BioZen's CEO Nate Kirchhofer.

At NREL, Cullen's team focuses on addressing the challenges associated with hydrogen (H2) storage: H2 has low volumetric energy density as a gas, and to increase that energy density, it must be liquefied, which requires energy and an extremely cold temperature of -423°F (-253°C or 20 Kelvin). The main issue then arises during the transfer between containers: to cryogenic liquid H2, everything looks scorching hot, so it flash boils, leading to significant boil-off losses. His solution employs a solid-state material to absorb the gas as it boils off, allowing for recapture and reuse, mitigating losses. This is critical research because H2 has many advantages as a storage medium, including the separation of Power and Energy (which conventional batteries fail at), but there are not good materials for storing it at ambient temperature (where Li-ion currently shines) despite proficiency storing at both cryogenic and hot temperatures.

At Activated Energy (one of the 27 companies in CalSEED Cohort 6 along with BioZen), Cullen's team is working to revolutionize energy storage with a system based on compressed liquefied carbon dioxide (CO2). The system discharges energy by releasing the high-pressure liquid CO2 through a turboexpander and then storing it in a low pressure solid state medium. This technology may be particularly appealing for urban environments due to its safety that addresses concerns associated with deploying energy-dense devices near residential areas.

Hang around for some discussion of efficiency, market segmentation, NIMBYism, and some advice from Cullen for individuals interested in entering the renewable energy or clean tech sectors. Hint: it's all about the people!

Recorded 14 November 2023.

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