U.S. EPA released a major new interpretation of “project emission accounting” under New Source Review.  Reversing the Obama EPA position, U.S. EPA will now allow facilities in determining whether a “project” will trigger New Source Review to account for both projected increases and decreases at the same time.  Key to this approach is determining what emission units are included in the project, and developing and tracking the projection.

This new interpretation will be controversial and likely challenged.  Also, states are not bound by U.S. EPA’s position and can interpret the state New Source Review requirements in a different manner.