Equity-driven investments in community energy systems: an optimization model applied to Washington State

This paper presents the development and application of the equity and climate impacts optimization in community energy (ECOCE) model, a mixed integer linear tool designed to optimize equity-driven investment in community solar projects (CSPs). By providing insight on a variety of impacts of CSP investments, including electricity bill savings, solar production, and greenhouse gas emissions reduction, the model assists policymakers in understanding the possible trade-offs in benefits and impacts of CSP investments. Using a detailed case study of a one-time $100 million investment in CSPs in Washington State, the model evaluates potential scenarios under various funding distributions to determine the optimal allocation of state funds. The study highlights considerations of geographical equity and participation, trade-offs between maximizing greenhouse gas reductions and minimizing energy burden, and the potential to use the model in different regional contexts. The findings suggest that targeted investments can provide significant electricity bill savings ($6.5–8.5 million annually) for low-income communities while contributing to state decarbonization goals (4–42 kTons of avoided emissions annually) in Washington State, though political and practical considerations may influence the feasibility of these optimized allocations. The ECOCE model provides a robust framework for decision-makers aiming to balance a variety of political, equity, and climate change mitigation considerations in the transition to renewable energy.