• Whether a unit’s emission rate or its total emissions over a specified time should
be used to determine if an efficiency improvement project increases emissions.
NETL further stated that several developments since the passing of the 1977 Clean Air Act
Amendments have failed to clarify these issues and made efficiency improvements risky and less
appealing to plant operators. On the other hand, NETL also stated that “[u]nder future scenarios,
the added value of higher efficiency in meeting GHG emissions limits, may prevent the NSR
from being utilized as a barrier to capital investments aimed at improving power plant
efficiency.”50