<p dir="ltr">The global energy transition presents significant challenges and opportunities for the resilience, economics, and environmental performance of distribution grids. This dissertation employs high-fidelity distribution grid analysis and optimization to understand how technology deployment impacts grid resilience in the face of extreme conditions and growing demands. </p><p dir="ltr">Chapter 2 investigates trade-offs and equity considerations in deploying backup power systems for community microgrids. Using a Grid-Aware Tradeoff Analysis (GATA) framework, this work integrates three-phase power flow feasibility with economic and social metrics to provide actionable insights for ensuring backup power reaches the most vulnerable populations. </p><p dir="ltr">Chapter 3 expands the analysis to the feeder level, developing a method to determine cost-effective, technically feasible deployment of hybrid energy systems for outage mitigation. This approach combines a Three-Phase Infeasibility Analysis - Multi-Period (TPIA-MP) model with an Energy Least Cost Optimization (ELCO) framework, showing how decentralized deployment can increase flexibility and resilience but also raise investment requirements. </p><p dir="ltr">Chapter 4 shifts the focus to the demand side, quantifying the grid-constrained adoption ceiling for residential electrification through heat pumps. The study integrates real-world data, techno-economic adoption modeling, and distribution grid power flow analysis to show that while 30 million households could adopt a particular heat pump technology economically, grid constraints limit feasible adoption to about 15 million households nationwide. </p><p dir="ltr">Collectively, these chapters demonstrate that high-fidelity grid modeling can inform both policy and technology planning by highlighting how supply-side and demand-side decisions interact to shape distribution system behavior. This dissertation offers a roadmap for building resilient, economically viable, and sustainable energy transitions that consider the realities of grid operations.</p>