The U.S. Department of Energy (DoE) has released a document defining what qualifies a building to be called “zero emissions”. The DoE states that they intend their definition to “support the buildings sector moving toward zero emissions and advance public- and private-sector climate goals.”
The document is called National Definition of a Zero Emissions Building, Part 1: Operational Emissions from Energy Use, Version 1. The DoE may release additional parts in the future covering other sources of building-related emissions such as emissions generated in the production and disposal of the materials used in its construction. The definition is not presently intended to impose a regulatory requirement on the building industry.
The obvious
Aspects of the definition are what one would expect: a zero emissions building should be free of on-site emissions from energy use and the power that is used in the building must be “clean”. To be considered clean, the power used at the site must be generated without creating greenhouse gases. The definition document lists four different ways in which this can be certified.
The definition applies to both the emissions generated by the building owner/operator and also by the tenants occupying the building. It does not allow the use of carbon offsets to achieve zero emissions.
The not so obvious
The definition put forward by the DoE also requires that a zero-emissions building be “energy efficient”, although it would be possible for an inefficient building to meet the zero emissions requirements outlined above. The definition provides several ways in which the building could be shown to be energy efficient, including existing buildings having an Energy Star rating of 75 or higher and a new building having an Energy Star rating of 90 or higher.
While DoE is not requiring the use of its definition of a zero emissions building, that does not mean that requiring it won’t be taken up by others. When EPA first made Energy Star Portfolio Manager available, its use was voluntary. However, eventually many local jurisdictions made its use a mandatory part of their reporting requirements.
The definition document is available here.
