Title IV of the CAAA focuses
on a particular set of NOx-emitting
sources–coal-fired electric utility
plants–and uses a two-phase strategy
to reduce emissions. Phase I
of the program has reduced NOx
emissions in the United States by
over 400,000 tons/year. These
reductions were achieved by the
installation of low-NOx burner
technology on dry-bottom, wallfired
boilers and tangentially fired
(T-fired) boilers (Group 1).
In Phase II, which begins in the
year 2000, EPA has established
lower emissions limits for Group 1
boilers and established limits for
Group 2 boilers. Group 2 boilers
include those applying cell-burner
technology, cyclone boilers, wetbottom
boilers, and other types of
coal-fired boilers.
The statute requires that emissions
control costs for Group 2
boilers be comparable to costs for
Phase I, Group 1 boilers. The regulations
allow for emissions averaging
in which the emissions levels
established by EPA are applied to
an entire group of boilers owned or
operated by a single company. It is
projected that the more stringent
Phase II limits will result in an additional
NOx reduction of 820,000
tons/year.