Ten questions concerning operational greenhouse gas (GHG) emissions accounting for electricity use in buildings

As building codes, standards, and rating systems increasingly require greenhouse gas (GHG) reporting across the building life cycle, the need for robust and decision-relevant methods for operational carbon accounting has become critical. This paper addresses operational GHG emissions accounting for buildings, with a particular focus on electricity use, which has emerged as the dominant energy carrier as building electrification accelerates. Structured around ten guiding questions, the paper first examines the institutional and conceptual foundations of operational GHG accounting, reviewing commonly used frameworks and standards, and identifying key gaps related to electricity emissions accounting. It then clarifies the distinction between attributional and consequential accounting perspectives and discusses how this choice influences the selection and interpretation of electricity emissions factors across different applications. The paper next explores electricity emissions factors, including the types of factors available, their calculation methods, data requirements, and sources of historical, real-time, and forecasted emissions signals. It highlights how grid dynamics—such as variable renewable energy deployment and spatial and temporal variation in electricity generation—affect marginal and average emissions estimates, and discusses approaches for evaluating the accuracy of marginal emissions factors. Finally, the paper examines the implications of emissions factor selection for building-scale and system-level decision-making, illustrating how misalignment between accounting methods and application context can influence estimated emissions. It concludes by discussing the integration of carbon signals into electricity markets and grid-interactive building operation. Together, these ten questions provide a structured reference for applying fit-for-purpose approaches to operational GHG emissions accounting for electricity use in buildings.