Electricity system capacity expansion models generally have coarse temporal, spatial, and process representations of grid operations, investment decisions, and infrastructure siting constraints. Such models have served the industry well during the long period of resource portfolios dominated by traditional fossil fuel and thermoelectric generation technologies and predictable peak demands. However, evolving uncertainties in climate/extreme weather, technology cost and performance, renewable resource availability, distributed generation and storage, and energy system policies present new dynamical and spatial challenges for maintaining resource adequacy, which require new modeling capabilities.