On June 13, 2024, the Boston Planning & Development Agency (“BPDA”) Board of Directors approved a proposed zoning text amendment regarding Net Zero Carbon (“NZC Zoning”) and authorized its submission to the Boston Zoning Commission for adoption. Under NZC Zoning, projects filed on or after July 1, 2025, must demonstrate Net Zero Carbon (“NZC”) readiness and provide embodied carbon reports during their planning and construction phases. The amendment applies to new buildings that are subject to development review under Article 80 of the Boston Zoning Code and have at least 20,000 square feet of gross floor area or 15 or more dwelling units. It also applies to additions of at least 50,000 square feet of gross floor area but exempts additions for “Hospital Use” as defined by the Zoning Code. The provision does not apply to renovation projects or changes of use that do not otherwise trigger the thresholds for new construction or additions. NZC Zoning amends Article 37 of the Zoning Code relating to Green Buildings and is intended to advance Boston's goal for carbon neutrality by introducing new sustainability requirements. The BPDA expects the zoning provision will support decarbonization of new buildings by advancing electrification, reducing use of fossil fuels, and encouraging the use of low-carbon materials. The new zoning does not replace the current LEED certifiability requirement, which remains in place, but it eliminates reference to the Boston Green Building credits.
The zoning amendment builds off of and complements Boston's Building Emissions Reduction and Disclosure Ordinance (“BERDO”), which was adopted in 2021. BERDO imposes annual greenhouse gas (“GHG”) emission limits on existing buildings, with the limits varying depending on building use. The limits become progressively more stringent over time until reaching net zero emissions by 2050 for all use categories. NZC Zoning takes this scheme a step further by requiring new buildings to be designed to meet the BERDO 2050 emission standards (net zero) upon construction. In effect, this will expedite the BERDO schedule for net zero compliance by moving emissions to zero for new projects starting on the 2025 effective date for the zoning amendment. However, hospitals, general manufacturing, and high ventilation laboratory buildings will have phased-in net zero emission requirements that push the net zero date out to 2035 for labs and 2045 for the other categories. Nevertheless, even for these three categories, NZC Zoning will accelerate the schedule required for existing buildings under BERDO. The phase-in process recognizes the complexities and unique energy demands these types of structures require, considering their specialized equipment and technological constraints.
BERDO (and, hence, NZC Zoning) provides three compliance options: (1) emission reduction; (2) use of renewable energy, including renewable energy certificates; and (3) alternative compliance payments (“ACP”), which are based on the average cost per metric ton (currently $234) of carbon dioxide to decarbonize buildings. Emission reductions are achieved through building retrofits or energy-efficient improvements. Renewable energy compliance reduces emissions from electricity through the installation or purchase of renewable energy—e.g., solar or wind. The ACP option allows building owners to comply by paying $234 for each metric ton of carbon dioxide emissions that exceeds their emissions limit.
The NZC Zoning amendment also requires projects to report on embodied carbon. Embodied carbon refers to carbon dioxide emissions associated with manufacturing, transportation, and construction of building materials throughout the entire life cycle of a product. According to the BPDA, it accounts for almost half of a building’s total GHG emissions over time. Larger projects, with at least 50,000 square feet of gross floor area must conduct an embodied carbon life cycle assessment. Smaller projects only need to identify their embodied carbon through a checklist or sustainability narrative in a format to be provided by the BPDA. The BPDA hopes to use the reports to better understand environmental and cost impacts of regulating embodied carbon and eventually move to a regulatory scheme limiting the amount used in new construction projects. Currently, there is no standardized approach to reporting and reducing embodied carbon, although Cambridge and Newton already have embodied carbon reporting requirements for construction materials (e.g., wood, concrete, steel, aluminum, and glass).
The new zoning will be implemented through the Article 80 development review process. As part of its initial Article 80 filing (e.g., the project notification form or small project review application), a project must demonstrate compliance with the net zero carbon requirements by completing a BPDA checklist and project narrative showing that the building is designed to be net zero prior to operation, or in other words "net zero ready." Preliminary embodied carbon information is required as well. Updates and refinements of the documentation are due before issuance of the building permit and certificate of occupancy to ensure the building is maintaining its NZC readiness. For large project review projects, the final embodied carbon life cycle assessment is due before issuance of the certification of compliance. Moreover, prior to operation, the developer must submit a Net Zero Greenhouse Gas Emissions Ready Acknowledgement Letter acknowledging that the project must comply with the GHG emissions standards under zoning and BERDO. Once the building is in operation, the BERDO program will take over and enforce annual compliance with emission standards established by zoning.
The NZC Zoning amendment now needs approval of the Boston Zoning Commission before it becomes added to the Zoning Code. The Zoning Commission is expected to consider the proposal at its July meeting.
