DoE Seeks Comment on Definition for Zero Emissions Buildings

In this climate-conscious world, builders and developers are expected to do their part by improving energy efficiency and reducing emissions from the structures they build. But how exactly to define the criteria to meet these goals has been a source of confusion and conflicting regulations that vary from state to state.

Now the U.S. Department of Energy has issued a draft definition for the term “Zero Emissions Buildings” (ZEB) that is intended to clarify the matter. It is inviting comment by February 5 from industry and other stakeholders through a request for information published in the Federal Register. The definition, when finalized, is intended to “serve as a clear market signal and consistent target, backed by measurable data, to help move the building sector to zero emissions.”

The goal is to achieve “a standardized, verifiable basis for defining a zero emissions building,” a DOE statement said. “A broadly accepted common minimum definition for a zero emissions building, as well as a pathway for verification, is foundational to efforts by public and private entities to transition the building sector to zero emissions.” Users can adopt the new framework “through multiple pathways” to achieve this goal.

The ZEB definition will apply to existing buildings and new construction of non-federally owned buildings. Federal buildings are governed by separate rules. “Almost 30% of U.S. greenhouse gas (GHG) emissions are from operating buildings, with 13% of U.S. GHG emissions from direct burning of fossil fuels within buildings. Buildings contribute an even higher percentage of U.S. GHG emissions when factoring in emissions from construction, materials, and refrigerant,” a DOE press release stated.

The draft minimum criteria for a ZEB are that it must be highly energy efficient, free of onsite emissions from energy use, and powered solely from clean energy.

To qualify as “highly energy efficient,” the building’s energy performance must be among the top 25% most efficient buildings in the market with a similar use and must be at least 10% lower than the IECC model code. To meet the standard for “free of onsite emissions,” the building’s direct greenhouse gas emissions from energy use must equal zero. And to be considered “powered solely from clean energy,” all its energy must be from carbon-free sources.

The RFI also includes specifications for methods of measuring building operational emissions and verification, and is subject to periodic reevaluations.

The RFI only applies to operational emissions and is termed “Part 1.” Further regulations to minimize the embodied carbon of the building and the impacts of refrigerants could be added later.

The Real Estate Roundtable has said it will submit comments on the draft proposal, but welcomed the effort. “A federal definition for ZEB could bring much-needed consistency to help CRE owners and investors establish long-term emissions goals for buildings,” it stated.

In a September 23 letter to EPA Administrator Michael Regan, the Roundtable noted that state and local governments are “escalating their enactment of Building Performance Standards.” It said this had resulted in a complex patchwork of laws and decarbonization frameworks. “The confusion and conflict among these myriad programs are getting worse. The ability for owners, developers, and financial institutions with national and global real estate portfolios to comply has become exceedingly difficult, impracticable, and in some cases, impossible,” the letter stated.