Long-Duration Energy Storage in Reliable Wind and Solar Electricity Systems

Citation

Dowling, Jacqueline Anne (2023) Long-Duration Energy Storage in Reliable Wind and Solar Electricity Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/gyzn-4n98. https://resolver.caltech.edu/CaltechTHESIS:06042023-203620894

Abstract

Several U.S. states mandate zero-carbon electricity systems based primarily on renewable technologies, such as wind and solar. Reliable and affordable electricity systems based on these variable resources may depend on the ability to store large quantities of low-cost energy over long timescales. This thesis combines techno-economic analysis with materials chemistry to advance long-duration energy storage in reliable wind and solar electricity systems. Our macro-energy model incorporated multi-decadal weather datasets and revealed unique long-duration energy storage roles, such as seasonal and multi-year storage, that increase the affordability of wind- and solar-based electricity, informing technology investments and policy. We find that low-cost energy storage, such as underground hydrogen, is valuable even if the charge/discharge cost is expensive. In U.S. wind and solar systems, hydrogen energy storage and conversion capital cost improvements are more valuable than efficiency improvements. Low-cost earth-abundant catalysts may be acceptable replacements for precious metal catalysts in proton exchange membrane electrolyzers despite lower efficiency for storage applications in wind and solar systems. We synthesized earth-abundant manganese antimony oxide catalysts via a new chemical vapor deposition route and assessed their long-term electrochemical durability for oxygen evolution. Multi-day tests confirmed the activity-stability tradeoff across the Mn:Sb composition space.

Thesis Files