Hot Rocks and H2: Modeling the Role of Emerging Technologies in the Electricity Sector

Abstract

In this dissertation I present work using system modeling methodologies to explore the role and impacts of two emerging technologies - enhanced geothermal power and hydrogen electrolysis - in a decarbonizing electricity sector. The dissertation is divided into four main chapters, as well as introductory and conclusory chapters that provide additional background and context.In Chapter 2 I and my collaborators explore the potential for enhanced geothermal systems (EGS) to provide flexible power generation and energy storage. We simulate EGS reservoirs under flexible operation and build a linear optimization model that accurately represents simulated behaviors while enabling optimization of power plant component sizing and hourly operations. We find that EGS plants can significantly increase their value when exposed to time-varying electricity prices by oversizing certain components and operating flexibly. We also find that flexibly-operated EGS plants could potentially store energy for hundreds of hours at high efficiency. In Chapter 3 we expand on this work by integrating the previously-developed flexible EGS formulation into an electricity system capacity expansion model and co-optimizing EGS power plant deployment and operation alongside other electricity technologies in a model of a decarbonizing Western US grid. We find that EGS could play a significantly larger role in electricity decarbonization than had been previously assumed if it is able to operate flexibly. In Chapter 4 we utilize newly-available field data from EGS demonstration projects to create near-term cost projections for the technology in the US, and model pathways to large-scale EGS adoption from the present day through 2050 using an experience curves approach. We find that if EGS can achieve initial deployment at high-potential sites in the Western US, it could fall in cost sufficiently to become a nationally-relevant electricity resource. Finally, in Chapter 5 I and collaborators explore a different emerging technology - hydrogen electrolysis - in a policy context. We study the impact of different possible implementations of the recently-passed Clean Hydrogen Production Tax Credit on mid-term electricity sector emissions outcomes, and find that three guardrails on clean power procurement - hourly matching, deliverability, and incrementality - are needed to mitigate large potential increases in electricity-sector emissions resulting from this policy.