Assessing the Potential to Reduce U.S. Building CO2 Emissions 80% by 2050

Buildings are responsible for 36% of CO2 emissions in the United States and will thus be integral to climate change mitigation; yet, no studies have comprehensively assessed the potential long-term CO2 emissions reductions from the U.S. buildings sector against national goals in a way that can be regularly updated in the future. We use Scout, a reproducible and granular model of U.S. building energy use, to investigate the potential for the U.S. buildings sector to reduce CO2 emissions 80% by 2050, consistent with the U.S. Mid-Century Strategy. We find that a combination of aggressive efficiency measures, electrification, and high renewable energy penetration can reduce CO2 emissions by 72%–78% relative to 2005 levels, just short of the target. Results are sufficiently disaggregated by technology and end use to inform targeted building energy policy approaches and establish a foundation for continual reassessment of technology development pathways that drive significant long-term emissions reductions. [Display omitted] •U.S. building CO2 emissions could be reduced up to 78% by 2050•Efficiency and low-carbon electrification are required to achieve this impact•Reductions are driven by heating energy use in existing residential buildings•Envelope, controls, and fuel switching measures drive cost-effective reductions The U.S. remains the second-largest contributor to global greenhouse gas emissions, and substantial reductions are necessary to reduce the risk of catastrophic climate change. The U.S. Mid Century Strategy (MCS) sets a goal of reducing total emissions 80% by 2050 relative to 2005 levels; as the buildings sector comprises 36% of energy-related CO2 emissions in the U.S., it is a critical piece of the MCS reduction strategy. We assess the feasibility of reducing U.S. building CO2 emissions 80% by 2050 using a reproducible and granular model of U.S. building energy use. Our results can inform energy and climate policy-making at the regional, national, and global levels and provide a benchmark for assessing emissions reductions in other sectors of the economy. Buildings are responsible for 36% of CO2 emissions in the U.S. and will thus be integral to climate change mitigation. We use Scout, a reproducible model of U.S. building energy use, to assess whether buildings can reduce CO2 emissions 80% by 2050, finding that aggressive efficiency measures and low-carbon electrification can reduce emissions 72%–78%. The analysis establishes a basis for periodic