Building energy retrofit simulation for exploring decarbonization pathways in a community-scale food-energy-water-waste nexus

The retrofit of existing buildings at a community scale can provide a huge opportunity to reduce the community's energy consumption and subsequent greenhouse gas (GHG) emissions in support of the United Nations agenda for net-zero emissions and decarbonization. This study demonstrates a community-scale food-energy-water -waste nexus through 6 alternatives (A1-A6) by highlighting decarbonization pathways with system dynamics modeling. Several potential retrofit alternatives are proposed for analyzing building energy consumption, energy requirements for rooftop or greenhouse crop production, and potential energy and water savings from renewable energy harvesting. Such a nexus analysis is designed to integrate (1) building energy consumption, (2) waste management and water consumption, and (3) GHG emissions based on life-cycle assessment to prioritize al-ternatives. The incorporation of solar photovoltaic (PV) systems (i.e., rooftop, parking lot, parking garage, and floating solar PV) sustains approximately 72% of net energy demand (alternative A3), while the integration of all solar, wind, and anaerobic digestion alternatives provides around 41% of net energy demand (alternative A6). It is vital to emphasize decarbonization pathways through the use of renewable energy by 2030 in alternative A5 (i. e., solar and wind energy) and A6, both of which avoid energy consumption from the utility grid and result in 250% total carbon emissions offset.