What constitutes a zero-emissions building? For some time now, it’s depended on who you asked, and there were multiple interpretations of the term. But that changed recently when the U.S. Department of Energy (DOE) issued a new national definition that outlines what a net-zero structure looks like.
The new definition was shepherded by DOE secretary Jennifer M. Granholm and endorsed by building industry professionals in a letter of support. The non-binding decree applies to buildings owned by public and private entities, not the federal government, which has its own set of rules for curbing greenhouse gas emissions.
A zero-emissions building, DOE said in a statement, is one that’s “highly energy efficient, does not emit greenhouse gases directly from energy use, and is powered solely by clean energy.” The new mandate will potentially help the U.S. achieve POTUS’s clean energy and climate goals, lower energy costs, cut air pollution, and create good-paying jobs.
By the numbers, a zero-emissions building must obtain an ENERGY STAR score of 75 or higher. If the building in question is ineligible for an ENERGY STAR score, other rules apply. Furthermore, direct greenhouse gas emissions (GHG) must equal zero with an exception for the use of emergency backup generators when grid power is unavailable.
The linguistic exercise is part of President Biden’s project to reduce U.S. building emissions 65 percent by 2035 and 90 percent by 2050. Today, according to the DOE, there are about 130 million buildings in the U.S. and approximately 25 percent of households struggle to pay their energy bills. This stock costs over $400 billion annually to heat, cool, light and power. And if current trends continue, there may be 40 million more new homes and 60 billion square feet of commercial space by 2050.
To counteract this increased energy consumption, DOE released a blueprint earlier this year for decarbonizing the built environment. The new national definition will play an important role in reaching this goal.
The mandate however is not a regulatory standard. Instead, it’s meant to provide guidance for public and private entities to optionally adopt. Also, DOE will not certify whether or not a particular building satisfies the new national definition. Rather, public and private entities hoping to meet the new benchmark will individually document and verify their stock to determine if it meets national standards.
The path toward a national definition began when industry leaders, academics, research labs, government agencies, and other stakeholders came together to form a draft definition last year. This information was published on EERE Exchange and the Federal Register in January 2024, and then accepted through March 6.
Looking ahead, the definition may change over time. DOE notes that it may someday address emissions from producing, transporting, installing, and disposing of building materials; minimizing the impacts of refrigerants; and other considerations.
