Next Steps for Boston's Zero Net Carbon Zoning After Zoning Commission Rejection
August 19, 2024
On August 14, the Boston Zoning Commission rejected the Zero Net Carbon (ZNC) Zoning Initiative for new buildings. The ZNC Zoning Initiative would apply to new buildings over 20,000 square feet or with 15+ units, or additions over 50,000 square feet (with an exception for hospitals). The zoning would have established new emissions requirements, mandating that new buildings be net zero emissions at the time of occupation, starting on July 1, 2025. Based on input from A Better City and other organizations, the ZNC Zoning Initiative included relaxed compliance timelines for certain sectors—hospitals and general manufacturing uses would have until 2045 to comply with the net zero emissions requirement, and labs and high ventilation buildings would have until 2035. In addition to the net zero emissions requirement, the zoning would continue to mandate that new buildings align with LEED standards and institute new embodied carbon reporting requirements.
Effective January 2024, the City of Boston requires that all new construction comply with the Municipal Opt-in Specialized Energy Code that includes high levels of efficiency and electrification readiness—many new buildings will be fully electric. The ZNC Zoning Initiative would build upon the code requirements mandating net zero emissions at occupation—meaning that the owners of new buildings must, from day one, pay to offset emissions associated with their electric use by choosing Power Purchase Agreements/Renewable Energy Credits/Community Choice Aggregation, etc.
A Better City’s most recent comments to the City of Boston emphasized that the ZNC Zoning initiative essentially penalizes new buildings for a dirty grid. In addition to the premium to build to the Municipal Opt-in Specialized Energy Code that encourages electric buildings, building owners would then need to pay to offset all electric (and other) emissions from the day of occupation. This additional cost is projected to range from $0.30-$0.80/square foot or $300,000 to $800,000 per year for a one million square foot all-electric commercial office building in downtown Boston that cannot have onsite solar. A mixed-use development with four all-electric buildings (affordable, market, condos and rentals) averaging 214,000 square feet each, built to passive house standards with onsite solar offsetting an average of 10% of electrical use per building, is projected to cost $92,000 to $157,000 to offset electric emissions per year. A 100% affordable all-electric building of 106,500 square feet, built to passive house standards with onsite solar offsetting approximately 14.5% of electrical use, is projected to result in an additional cost of $16,000 to $26,500 to offset electric emissions per year. It is important to note that onsite solar is not feasible for the vast majority of developments in downtown Boston because Eversource operates an underground network system that does not allow interconnection. Additionally, solar plus storage options are also limited because the Boston Fire Department requires storage to be located outside a building with setbacks.
To address these concerns, A Better City recommended to the City that all new buildings have until 2035 to achieve net zero emissions—when the grid will be cleaner and the associated costs to offset electricity use will therefore be less burdensome. Per BERDO’s approved policies from December 2023, Appendix A (page 20) “Projected Grid Emissions Factors,” 2035 is the year when the ISO New England grid’s electricity emissions are projected to be as clean as natural gas emissions. In other words, until 2035, using natural gas produces fewer GHG emissions than using electricity.
The City of Boston is planning to bring the ZNC Zoning Initiative back to the Zoning Commission with additional information and engagement as requested by Zoning Commissioners. A Better City will continue to work with members and with the City as the ZNC Zoning progresses. For any additional information, questions or comments, feel free to reach out to Yve Torrie.
