UC Davis

Interest in hydrogen as a clean source of energy has grown considerably over the past decade. With its ambitious climate goals and a vibrant economy, California looks poised to become one of the major hydrogen hubs in the country. However, insufficient infrastructure to support demand and lack of economies of scale, are critical factors that have impeded the uptake of hydrogen in California. Infrastructure requirements span across the supply chain including production, delivery, and distribution. Strong early investments are required, with a clear vision of where and when the future hydrogen system buildout will happen. The first chapter in my dissertation employs a suite of hydrogen supply chain (HSC) models developed by the US Department of Energy (DOE), to explore technology feasibilities (particularly for California) and identify factors that are most critical for achieving the lowest levelized costs of hydrogen across the supply chain. I find that feedstock prices, size of the hydrogen market and infrastructure utilization are the prominent parameters that affect the levelized costs of hydrogen.These factors would evolve over time and space. Choosing a cost optimal technology in every section of the HSC after considering these factors is a complex optimization problem. I worked with researchers at the National Renewable Energy Laboratory (NREL) and Institute of Transportation studies (ITS, UC Davis) to upgrade NREL’s Scenario Evaluation and Regionalization Analysis Model (SERA), a hydrogen infrastructure optimization model. I then employ SERA to understand how demand uncertainties, sector coupling (between the HSC and electricity grid) and renewable hydrogen policies could impact the buildout of hydrogen infrastructures in the western United States, primarily to meet California’s projected hydrogen demands from 2025-2050. We find that falling electricity prices and electrolyzer capital expenditures encourage investments in renewable hydrogen production (grid connected electrolysis) across the Western states, more so outside California. Consequently, a complete reliance on the electricity grid for hydrogen supply can be expensive for California, as there needs to be a more elaborate build out of delivery infrastructure. If California’s electricity grid rates continue to be higher (as compared to neighboring states), its regional hydrogen imports could range between 30-75% of its demand by 2050. With more favorable rate structures for grid-connected electrolyzers in California, some of those regional imports could be offset. Investments in blue hydrogen (fossil derived with carbon capture and sequestration) in California could continue well beyond 2030, but some of it could be disincentivized with additional renewable hydrogen mandates. Evolution of the hydrogen delivery network is found to be driven by the rate of demand growth and its spatial distribution. For meeting road transportation demands, which is very distributed and growing only incrementally, hydrogen delivery using trucks seems to be cost-effective in most scenarios. Within trucking, liquid trucks present a better opportunity while demand scales up. But with large, concentrated demand (like in hubs), pipelines are the preferred option for hydrogen delivery. Generally, investments in building dedicated hydrogen pipelines require high degrees of demand certainty, which could be spurred by farsighted policy incentives. Line packing of hydrogen pipelines could be a valuable hydrogen storage proposition for California, which does not have access to some of the cheap underground bulk storage options (like salt caverns) within state. I demonstrate that long-term investment planning (like for 25 years) reduces system costs in all scenarios and is a critical piece in driving down the costs of hydrogen usage. Given that the hydrogen ecosystem is still very nascent, much of the investment decisions will be policy driven, not only regional policy but global. In the last chapter of my dissertation, I review the status of hydrogen policies globally. I identify major economies like Japan, South Korea, Germany, and California as early adopters with specific policies that have encouraged hydrogen across different sectors, but with varying levels of adoption. Hydrogen is identified as a potent decarbonization vector by all these jurisdictions and there are substantial opportunities for collaborations that could help scale up a global hydrogen economy.