Towers rise around downtown Boston’s Winthrop Square. Photo by James Sanna | Banker & Tradesman Staff

New developments in Boston will be required to comply with strict new limits on carbon emissions under a zoning amendment that won support from the Boston Planning & Development Agency’s directors Thursday night.

The net zero carbon zoning will take effect for projects submitted for approval beginning in July 2025. It applies to projects that include at least 15 housing units or 20,000 square feet of construction, and additions to existing buildings of 50,000 square feet or more.

“This is something that cities must do. This is the existential threat of our time in terms of climate change and it’s up to cities to lead,” said BPDA board member Matthew O’Malley, chief sustainability officer at Vicinity Energy and a former Boston city councilor.

Projects will be required to be designed to achieve net zero emissions standards upon completion. Developers can comply by use of non-fossil fuel building systems such as electricity and solar, purchases of renewable energy credits, or submission of alternative compliance payments to the city’s equitable emissions investment fund, which supports decarbonization in environmental justice communities. The compliance payments could add up to 5.5 percent to overall operational costs, the BPDA estimates.

BPDA board member Raheem Shepard questioned whether the new requirements would deter development activity in Boston or put the city at a disadvantage to suburban sites.

Astrid Walker-Stewart, the BPDA’s zoning reform planner, said the July 2025 deadline was selected to cushion the financial impacts on developers, who also face an increase in linkage fees starting in January.

Real estate organizations have warned the new regulations will make it harder to finance projects, amid a downturn in commercial and multifamily development because of higher lending and project costs. They also questioned whether utilities can provide sufficient electric grid capacity and timely hookups for new projects.

The new net zero carbon building code sets later deadlines for building types with higher energy usage. Hospitals and manufacturing buildings are required to be designed to meet net zero emission standards by 2045, while lab buildings will have a 2035 deadline.

The new regulations are similar to those that apply to existing buildings under Boston’s Building Emissions Reduction Disclosure Ordinance (BERDO), which encourages retrofits to replace fossil fuel building systems.

The net zero carbon ordinance also requires developers to submit information on embodied carbon, measuring the carbon footprint associated with production of building materials. It does not include specific regulations on embodied carbon, but the intent is to encourage reuse of existing buildings, Walker-Stewart said.

The changes are subject to final approval by the Boston Zoning Commission.

Boston Sets Deadline to Limit Emissions in New Developments

by Steve Adams time to read: 2 min