The simple question What is a Zero-Energy Building? occasionally triggers some controversy. It's good to have common definitions.
The US Department of Energy (DOE) has a new 22-page report entitled A Common Definition for Zero Energy Buildings.
They define a Zero Energy Building (ZEB) as:
"An energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy."
- The term "energy-efficient building" is not defined.
- Wood and wood pellets are considered delivered energy, and therefore treated like gas or oil (unless harvested on-site).
- The report endorses Conversion Factors. For example, you can overproduce electricity to get credit for delivered natural gas consumption at a rate of about 3-to-1.
The controversies will certainly continue. Allison Bailes provides some commentary on the report here.
Related: Mother Earth News article, "What Is a Net-Zero Home?"