Occupancy behavior-informed PV–battery sizing for resilient and sufficient buildings under climate-related disruptions

• Typical critical load identification brings human behavior into the loop. • Just-enough PV-battery design cuts system size by up to 85 %. • Behavior adaptation reduces daily critical load by up to 75 % in U.S. cities. • Proposed systems shift peak load by 89.3 % and achieve 171 days of grid independence. • Thermal resilience improves by 95.5 % in heat and 84.5 % in cold conditions. The changing climate has led to increasingly frequent climate-induced disruptive events such as extreme heat and cold, causing significant economic and societal losses. While PV-battery systems can effectively enhance building energy resilience, oversized systems may introduce economic challenges, operational inefficiencies, and environmental burdens. To identify just-enough PV–battery system sizes that support both resilience and energy sufficiency, we extend the concept of building energy sufficiency to the microgrid scale by 1) supporting resilience through minimal yet sufficient system design, and 2) enabling optimal operation to avoid energy waste during normal conditions. To achieve this, we investigate the critical role of occupant behavior adaptation under disruptive events and develop a resilience–sufficiency co-design and operation framework, evaluated across seven major U.S. cities. Results show that behavior adaptation under disruptive events reduces critical loads by 28–83 %—with activity adaptation achieving 28–40 %, comfort adaptation adding 9–20 %, and mobility adaptation contributing up to 17 %—enabling PV downsizing of up to 85 % in Miami and battery capacity reduction of 68.9 % in Phoenix. The proposed approach achieves peak load reductions of 66–89.3 %, annual load shifting of 69.1–94.9 %, and bill savings of 65.9–93.9 % across cities. It also reduces unmet load by up to 90 %, lowers failure ratios by 9–32.6 %, and improves load cover ratio by up to 22.9 % during extreme events. Thermal resilience improves by 83.7–95.5 % for overheating and 74.7–84.5 % for extreme cold. From a sufficiency perspective, the framework delivers 98–294 days of grid independence, self-consumption ratios of 57–98.7 %, and self-sufficiency ratios of 63.9–93.5 %, highlighting its potential to guide “just-enough” PV–battery microgrid designs that balance resilience, flexibility, and efficiency.