Quantifying electricity-related carbon emission factors of low-emission neighborhoods: A comparison of different methods

Abstract

Buildings currently account for over 30% of final energy use and 19% of European energy-related greenhouse gas (GHG) emissions, making reductions in this sector highly significant. Zero Emission Buildings (ZEBs) and Zero Emission Neighborhoods (ZENs) have emerged as a potential solution. They aim to achieve net-zero emissions by offsetting embodied emissions through power export from local renewable energy sources (RES), typically solar photovoltaic (PV). While accounting for material-related emissions follows well-established standards, emissions caused by electricity demand remain challenging to quantify. This paper investigates various methods for quantifying emissions linked to energy consumption and local production in a ZEN. We also examine how different time resolutions and geographical scopes impact the final outcomes. We test these calculation approaches on a ZEN case study, exploring how they influence the required investments in local RES. Our results indicate very large variations across emission factor methods and the potential for biases towards specific technologies depending on the methodological choices. In order to ensure that ZENs actually contribute to limiting GHG emissions, we recommend that the approach for calculating emission factors be region-specific and adjustable over time.