C29 -- Strategies and Policies for Achieving Net Zero Carbon in the Built Environment: A Comparative Analysis of Operational and Embodied Carbon Approaches in the United States

As global concerns over climate change intensify, achieving net-zero carbon emissions within the built environment emerges as a critical objective. This paper conducts a comprehensive analysis of strategies and policies implemented across various jurisdictions in the United States, focusing on how they address operational and embodied carbon in commercial buildings.

The paper examines federal and local initiatives, including energy codes/standards and the Building Performance Standards Coalition aimed at reducing energy consumption and associated carbon emissions in new and existing buildings. The analysis further explores existing building policies, comparing the effectiveness of EUI-based approaches like Washington DC’s BEPS program with carbon emission-based approaches like New York City’s Local Law 97. It also discusses recent updates to energy codes/standards, such as ASHRAE 90.1-2022 and California’s Title 24 2022, highlighting the emphasis on electrification and on-site renewable energy as crucial elements for achieving net-zero goals in new buildings.

In embodied carbon, federal and state regulations, such as the U.S. General Services Administration's Buy Clean Initiative and California's CalGreen code, aim to reduce embodied carbon associated with building materials. They can be compared to life cycle assessment (LCA) requirements implemented in cities like Vancouver and Toronto.

The paper emphasizes the critical role of electrification in achieving net-zero buildings for both new and existing buildings and points out the need for updated energy codes/standards that promote and incentivize electrification, coupled with increased utilization of on-site renewable energy and battery storage. It also emphasizes the importance of aligning building decarbonization policies with the future trajectory of the energy grid and provides clear projections for emission factors to facilitate compliance and informed decision-making.