Cambridge city staff told the Health and Environment Committee on a convening of city officials and utility partners that the Building Energy Use Disclosure Ordinance (BUTO) will require the largest nonresidential buildings to begin reducing emissions in January 2026 and reach net zero on a faster timetable than smaller buildings.

Julie Warmser, chief climate officer for the city, said Cambridge’s climate commitment and decades of planning make the city well positioned to act, but that meeting the goals will require coordination and time: “it will take all of us all in order to achieve those goals.”

BUTO applies to large nonresidential buildings and, as explained by Nikhil McCartney, senior program manager for decarbonization, the largest nonresidential buildings (100,000 square feet and larger) must begin cutting emissions in January 2026 and reach net‑zero emissions by 2035; mid‑sized nonresidential buildings begin reduction steps in 2030 and are required to be net‑zero by 2050. McCartney said, “BUTO addresses emissions from large non residential buildings,” and noted the ordinance includes compliance flexibility: limited use of offsets for the largest buildings between 2030 and 2050, hardship and deferral mechanisms and alternative compliance credits.

Why it matters: Cambridge staff say building operations account for the lion’s share of city emissions; local compliance timelines put near‑term obligations on owners of the largest nonresidential properties and launch a regulatory and support process that will affect development and existing building retrofits.

What the city is providing: staff described multiple technical and financing tools to help owners comply. Those include Mass Save incentives, a MassCEC “beta pilot” that provides customized decarbonization audits, and Property Assessed Clean Energy (PACE) financing for longer‑term building upgrades. City programs highlighted included Electrify Cambridge (home decarbonization support), a helpline that answered roughly 400 calls last year, a green equipment program funded with ARPA dollars (the presentation reported $750,000 already allocated to support 20 businesses, with individual awards ranging from about $300 to $150,000), and a large‑roof solar assistance program that engaged more than 40 property owners.

Renewable electricity purchasing and aggregation: the city manages Cambridge Community Electricity, an aggregation program that serves more than 42,000 residential and business accounts. Staff said the aggregation has saved customers roughly $90 million versus Eversource rates since 2017 and currently offers a default product that is 50% renewable. To increase renewable supply, the city has signed long‑term virtual power purchase agreements (VPPAs): a wind farm in North Dakota that staff said will cover 100% of the city’s municipal electric load and a solar farm in Illinois that will cover about 17% of the aggregation’s load, together approaching roughly half of aggregation demand from these contracts.

Thermal energy networks and feasibility work: city staff described a one‑year feasibility study begun in February that screened about 38 candidate sites for district‑scale thermal energy networks (water‑based loops that supply heating and cooling). Staff said a sample mixed‑use cluster in the analysis could meet about 98% of annual heating and cooling demand but that feasibility questions remain: borefield area needs, construction impacts to parks and parking, high upfront costs, congested underground utilities and ownership/operations models. The city plans to engage building owners and residents on candidate pilot sites and to complete technical, financial and emissions analyses.

Rulemaking and next steps: staff said the city will publish a draft of final BUTO regulations for public comment in December and will seat a review board to adjudicate hardship and deferral requests beginning in 2026. Staff also said they are exploring ways to expand access to renewable electricity purchasing for smaller entities and to make the city’s VPPA lessons more accessible to mid‑sized organizations.

Outlook and context: staff reported municipal progress — the presentation showed municipal emissions down roughly 39% since 2008 and significant gains in on‑site solar and fleet electrification — but they also warned of persistent barriers, including the high upfront cost of retrofits, limited federal funding and the need for long‑lead infrastructure investments at the utility level.

Sources: presentation and Q&A at the Health and Environment Committee meeting (city staff: Julie Warmser; Nikhil McCartney; Megan Shaw; Irina Sidorenko).