Renewable Energy Generation and Storage: From Microwires to Macro-Energy Systems

Citation

Kennedy, Kathleen Marie (2021) Renewable Energy Generation and Storage: From Microwires to Macro-Energy Systems. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/nsmj-tq29. https://resolver.caltech.edu/CaltechTHESIS:10142020-161631454

Abstract

Current trajectories require urgent action to reach net-zero greenhouse gas emissions targets. This thesis focuses on efforts to support decarbonization through the development of solar fuels devices to produce green hydrogen and through macro-energy systems modeling.

Long-term stability of light-absorbing materials remains a substantial barrier to the viability of solar fuel devices. In this thesis, we identify corrosion pathways in TiO₂-protected silicon microwire arrays in a polymer membrane either attached to a substrate or free-standing. Both top-down and bottom-up corrosion processes were observed in both morphologies, with top-down corrosion arising from defects in the TiO₂ protection layer and bottom-up corrosion occurring through the substrate and membrane.

Moving to a systems perspective, we use a macro-scale energy model with historical demand in conjunction with hourly historical weather data to analyze the role of concentrated solar power (CSP) with thermal energy storage (TES) relative to photovoltaics (PV) and batteries in an idealized least-cost wind/solar/storage system that reliably meets hourly demand. We find that CSP+TES occupies a small niche providing valuable grid services by adding flexibility due to the favorable cost of storing energy in TES compared to batteries. Consequently, CSP does not compete directly with PV, but rather TES competes with short-duration storage from batteries, with the coupled CSP technology providing cost-effective grid services to achieve reliability. A cost-sensitivity analysis shows that penetration of CSP+TES in this idealized wind/solar/storage electricity system is primarily limited by the relatively high current CSP generation costs.

Thesis Files