Energy Science and Engineering Seminar - Two Talks

Viscous-Dominated Flow Experiments for Hydrogen Storage in Saline Aquifers

Underground hydrogen storage (UHS) is a potential long-term solution for net-zero energy storage. There have been numerous simulations studies on the feasibility of UHS in porous media such as saline aquifers, but very few experimental studies to complement them. This seminar will examine core-scale experiments for UHS, and how observations from these studies compare with numerical simulation studies.

An analog fluid system of nitrogen (N2) and viscosified brine, and a vertically oriented sandstone core are used to simulate hydrogen (H2) and brine in a saline aquifer at storage conditions. UHS is simulated through cycles consisting of gas injection, shut-in, and production while subjected to x-ray computed tomography (CT). We present the results in 1D, 2D, and 3D visualizations. The effect of permeability heterogeneity is shown through core-scale simulations based on our experimental results.

Speaker: Jimin Zhou, Stanford University

Nationwide Thermal Earth Modeling and Techno-economics of Enhanced Geothermal Systems

Conventional geothermal systems are geographically limited because they require the natural co-occurrence of high rock temperature, in-situ fluid for heat transport, and permeable or fractured rock for fluid flow. Recent technological advancements and field implementations have successfully demonstrated Enhanced Geothermal Systems (EGS), where heat transport and fluid flow are supplemented artificially through water injection and rock stimulation. EGS are applicable across diverse geographies, as naturally and sufficiently elevated subsurface temperatures are always present at certain depths. We conducted a comprehensive techno-economic analysis to evaluate EGS potential across the continental United States and Alaska. Our approach involved developing a nationwide thermal Earth model for depths down to 20 km with spatial resolution of 18 km². We then integrated techno-economic input data and models, including geothermal resource characteristics, capital and operational costs, weather patterns, proximity to transmission lines, among other factors. The majority of EGS supply potential was found in the Western and Southwestern regions of the United States, with California, Oregon, Nevada, and Texas showing the greatest EGS capacity potential. We identified various EGS targets with a competitive levelized cost of electricity in the range of 40 - 60 USD/MWh.

Speaker: Mohammad Aljubran, Stanford University