A Technical and Systems Analysis of Hydrogen Fuel in Renewable Energy Systems

Citation

Rinaldi, Katherine Zoe (2022) A Technical and Systems Analysis of Hydrogen Fuel in Renewable Energy Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/h8x1-xb98. https://resolver.caltech.edu/CaltechTHESIS:06222021-223726087

Abstract

Within the next century, we must tackle the dual challenges of continuing to meet the increasing global demand for energy services while stabilizing global temperatures to mitigate the effects of anthropogenic climate change. Doing so will require a major restructuring of all energy services on a global scale. Here, we contribute to the understanding of the role of hydrogen fuel in net-zero emissions systems from both a technical and systems perspective.

From the technical perspective, we evaluate the activation mechanism of an electrodeposited cobalt selenide hydrogen evolution reaction (HER) catalyst using operando Raman spectroscopy. During this activation process these films, which originally show no catalytic activity toward HER, undergo a compositional change in which selenium in the form of loose, polymeric chains is electrochemically reduced from the material. This work provides a facile method towards investigating catalytic materials under operando conditions, elucidates the changes that occur in this cobalt selenide material during the activation step, and offers potential paths toward the improvement of the cobalt selenide catalyst.

At the systems level, we use hourly weather data over multiple decades and historical electricity demand data to analyze the gaps between wind and solar supply and electricity demand for California (CA) and the Western Interconnect (WECC). We quantify the occurrence of resource droughts when the daily power from each resource was less than half of the 39-year daily mean for that day of the year. Using a macro-scale electricity model, we then evaluate the potential for both long-term storage (in the form of power-to-gas-to-power) and more geographically diverse generation resources to minimize system costs. For wind-solar-battery electricity systems, meeting California demand with WECC generation resources reduces the cost by 9% compared to constraining resources entirely to California. Adding long-duration storage lowers system costs by 21% when treating California as an island. This data-driven analysis quantifies rare weather-related events and provides an understanding that can be used to inform stakeholders in future electricity systems.

Thesis Files