Zero net energy, once a wild-eyed, seemingly unattainable vision, isn’t exactly mainstream, but the concept is definitely taking root in North America: A new report says the number of buildings either at or reaching for the standard has more than doubled in the past two years.

Zero net energy buildings are defined as those that generate as much power from onsite energy sources as they consume, and on that count there are now 32 buildings and one “district” (a group of buildings) that meet the ZNE mark, according to the New Buildings Institute [PDF].

But to get a broader gauge of the ZNE trend, as it had in 2012 the NBI also counted up zero net energy buildings that hadn’t yet put in the full year of performance required, as well as buildings that were efficient enough to meet the ZNE standard but didn’t have the onsite generation component. They found 213 such buildings as 2014 dawned, compared to 99 in 2012.

“While this remains a relatively small set of buildings, the growth and diversity are important indicators for what we should expect in the coming years,” Ralph DiNola, executive director of New Buildings Institute, said in a statement.

My favorite fact from the NBI’s 2014 report [PDF]:

ZNE buildings use only a quarter of the energy of average buildings. Measured energy consumption of the ZNE buildings is only about one-quarter of the average commercial building energy use today. The average verified Energy Use Index (EUI)4 of these buildings is 21 kBtu/sf/yr.

Among other key findings in the NBI report: ZNE districts are a growing trend, with 18 identified; private sector ZNE development is climbing, comprising 26 percent of verified and emerging buildings (like the Walgreen’s store in the Chicago area that recently opened); renovations are claiming a ZNE role, at 24 percent of verified buildings; and ZNE isn’t restricted by climate – it’s happening in all eight U.S. Department of Energy climate zones. You can get a sense of this geographical diversity with the NBI’s interactive map of ZNE verified buildings.

* Pete Danko, EarthTechling