Abstract
California's ambitious climate targets rely heavily on the rapid deployment of distributed solar photovoltaics (PV). However, historical adoption patterns reveal deep socioeconomic disparities, leaving disadvantaged communities (DACs) disproportionately behind. As the state transitions from Net Energy Metering (NEM 2.0) to the Net Billing Tariff (NBT), targeted subsidy programs are vital to ensure an equitable energy transition. This study presents an Equity-Weighted Multi-Criteria Decision Analysis (MCDA) framework designed to optimize the spatial allocation of rooftop solar subsidies across California's DAC census tracts. Integrating spatial datasets from CalEnviroScreen 4.0, the National Renewable Energy Laboratory (NREL), and utility grid hosting capacity maps, we evaluate eligible tracts under three policy scenarios: Techno-Economic, Balanced, and Equity-Heavy. The results demonstrate that traditional efficiency-based allocation models disproportionately favor coastal, higher-income tracts within DAC designations. Conversely, our equity-weighted models shift critical funding toward inland, high-pollution-burden areas such as the Central Valley and the Inland Empire. By balancing grid constraints, solar resource quality, and cumulative environmental justice indicators, this framework offers policymakers a transparent, robust tool to maximize both carbon mitigation and social equity.
