As climate change drives more frequent extreme weather events, ensuring building habitability during power outages—known as passive survivability—has become a key resilience strategy. Passive building technologies, such as envelope and window upgrades, not only help maintain safe indoor conditions during outages but also reduce and shift electricity demand—benefits that are increasingly relevant as rising temperatures exacerbate peak demand. Yet, their grid-level cost savings and climate adaptation value remain unquantified. This study addresses that gap by modeling how investments in building envelope and windows upgrades affect the passive survivability of residential buildings during concurrent heatwaves and power outages, as well as bulk power system investments, operations, and costs. We use a multi-model framework linking building energy simulations with long-term capacity expansion modeling under a No Climate Change and midcentury RCP 4.5 scenario. We find that widespread adoption of upgrades can reduce peak demand below No Climate Change levels, improve generation efficiency, and lower system costs by as much as $2.8 billion/year (4%)—while improving thermal safety during extreme heat events. Accounting for these grid benefits reduces the effective cost of upgrades by over 50%, offering a new pathway to fund building resilience through measurable power system benefits.
Underground hydrogen storage (UHS) in depleted porous media offers a suitable, scalable, and large-scale approach for accommodating high storage capacities and enabling seasonal energy balancing. However, the full system-level feasibility and cost-effectiveness of underground storage of concentrated solar power–derived hydrogen (H2) under realistic operating conditions in the low-solar-resource season remain insufficiently investigated. In this context, this paper develops a globally applicable techno-economic framework for UHS configurations, integrating subsurface injection, storage within a depleted gas reservoir, purification, and pipeline transmission. System performance is evaluated using compositional reservoir simulations across varying reservoir and operational parameters, alongside equipment sizing and analysis of the levelised cost of hydrogen storage (LCOHS). In addition, during the low-solar-resource season, a portion of the upstream equipment energy demand is met by H2-based backup systems, with fuel cells and gas turbines comparatively evaluated within the model. Our results quantify the critical dependency of H2 recovery rate and LCOHS on petrophysical characteristics of the subsurface reservoirs. These findings demonstrate that the coupled interplay between reservoir properties and surface facility strategies is the key determinant of performance in repurposing geological reservoirs for H2 storage, providing a foundation for designing viable large-scale UHS systems.
