Full decarbonization of the U.S. energy system to meet climate goals requires aggressive emissions reductions across energy end uses; however, prevailing policies focus on end-use electrification and clean energy supply rather than a broader set of demand-side solutions. We assess multiple CO2 emissions reduction pathways to mid-century for U.S. buildings, which are among the largest sources of CO2 emissions across end-use sectors. We find potential for up to a 91% reduction in building CO2 emissions from 2005 levels by 2050 using a portfolio of efficiency, load flexibility, and electrification alongside rapid grid decarbonization. Demand-side measures could account for nearly half of overall emissions reductions, with building efficiency delivering more than double the emissions reductions of electrification measures in the near term. Further, building efficiency and flexibility would generate up to $122 billion in annual power system cost savings by 2050, offsetting nearly half the incremental cost of full grid decarbonization. Presented on April 25, 2022.

Buildings are energy-intensive and a primary source of US end-use sector carbon emissions. Although building emissions today are 25% below their 2005 peak, far deeper reductions are needed to reach the US 2050 net-zero emissions goal. However, plausible decarbonization pathways that consider both buildings and their interactions with the power grid remain poorly understood. Here, we couple detailed modeling of building energy use and the grid to quantify building decarbonization potential and associated grid impacts. We find up to a 91% reduction in building CO2 emissions from 2005 levels by 2050 using a portfolio of building efficiency, demand flexibility, and electrification measures alongside rapid grid decarbonization. Building efficiency and flexibility could generate up to $107 billion in annual power system cost savings by 2050, offsetting over a third of the incremental cost of full grid decarbonization. Our results underscore multiple benefits of demand-side solutions for deep decarbonization of US buildings.