1
Technical
Support
Document
for
the
Clean
Air
Interstate
Rule
Notice
of
Final
Rulemaking
Technical
Support
Document
on
Changes
from
the
Proposed
to
the
Final
Rule
for
§
§
51.121,
51.123,
and
51.124
March
2005
Prepared
by
Office
of
Air
and
Radiation
U.
S.
Environmental
Protection
Agency
EPA
Docket:
OAR
2003­
0053
2
Technical
Support
Document
on
Changes
from
the
Proposed
to
the
Final
Rule
for
§
§
51.121,
51.123,
and
51.124
The
final
rules,
§
§
51.121,
51.123,
and
51.124,
setting
forth
the
CAIR
requirements
for
SIP
revisions
include
changes
from
the
proposed
regulatory
text.
(
Note
that
sections
VII,
VIII,
and
IX
of
the
preamble
to
today's
action
highlight
the
more
significant
modifications
included
in
the
final
rules.)

Changes
to
§
51.121
The
proposal
did
not
include
regulatory
text
revising
§
51.121.
The
proposal
discussed
the
ability
of
States
to
meet
the
NO
X
reduction
requirements
for
EGUs
otherwise
imposed
under
the
NO
X
SIP
Call
through
compliance
with
NO
X
reduction
requirements
for
EGUs
under
the
CAIR
and
discussed
the
extent
to
which
the
Administrator
would
continue
to
administer
the
NO
X
Budget
Trading
Program.
The
final
rule
revises
§
51.121
to
terminate
the
role
of
the
Administrator
in
administering
the
NO
X
Budget
Trading
Program
under
the
NO
X
SIP
Call
for
any
ozone
season
after
September
30,
2008.
The
rule
revision
provides
that
States
that
adopted
the
NO
X
Budget
Trading
Program
must
adopt
additional
control
measures
to
achieve
the
reductions
otherwise
projected
to
be
achieved
under
the
NO
X
Budget
Trading
Program
after
2008.
However,
the
rule
revision
references
provisions
in
§
51.123
allowing
States
in
effect
replace
the
NO
X
Budget
Trading
Program
by
adopting
the
CAIR
NO
X
Ozone
Season
Trading
Program,
expanded
to
include
the
non­
EGUs
in
the
State's
NO
X
Budget
Trading
Program,
if
certain
requirements
are
met.

Changes
to
NO
X­
related
SIP
revision
requirements
in
§
51.123
The
three
most
important
types
of
changes
in
the
final
§
51.123
from
the
proposed
regulatory
text
are
as
follows.
The
first
type
of
changes
involve
setting
forth
similar,
but
separate,
SIP
revision
requirements
with
regard
to
annual
NO
X
emissions
significantly
contributing
to
PM
2.5
nonattainment
and
with
regard
to
ozone
season
NO
X
emissions
significantly
contributing
to
ozone
nonattainment.
The
final
rule
provisions
also
allow
Rhode
Island
and
New
Hampshire
to
adopt
the
CAIR
NO
X
Ozone
Season
Trading
Program,
if
certain
requirements
are
met.

The
second
type
of
changes
from
proposed
regulatory
text
involves
allowing
States
the
flexibility
to
adopt
one,
two,
or
three
of
the
model
trading
rules
(
i.
e.,
the
NO
X
Annual
Trading
Program,
SO
2
Trading
Program,
or
NO
X
Ozone
Season
Trading
Program).
Similar
changes
are
in
the
final
§
51.124.
The
proposed
regulatory
text
required
that
States
adopt
both
the
NO
X
and
the
SO
2
model
trading
programs.

The
third
type
of
changes
from
proposed
regulatory
text
involves
moving
the
NO
X
compliance
deadlines
forward
one
year,
from
2010
to
2009,
in
response
to
significant
concern
raised
by
commenters
concerning
the
timing
of
the
reductions
and
the
ability
of
State
to
use
such
3
reductions
to
help
achieve
attainment
by
the
required
attainment
deadlines.
Changes
concerning
the
NO
X
compliance
deadline
change
are
also
reflected
in
the
CAIR
NO
X
model
trading
rules.

Other
changes
from
proposed
regulatory
text,
most
of
which
clarify
proposed
provisions
or
implement
the
types
of
changes
discussed
above,
include:

1.
Identification
of
which
provisions
affect
which
States;
some
States
have
both
annual
and
ozone
season
NO
X
requirements,
some
only
have
one
or
the
other.
2.
Addition
of
compliance
supplement
pool
provisions
for
States
with
annual
NO
X
reduction
requirements.
3.
Clarification
of
the
requirements
for
using
non­
EGU
emission
reductions
to
meet
a
State's
annual
or
ozone
season
NO
X
reduction
requirements.
Similar
clarification
is
made
in
§
51.124
with
regard
to
meeting
annual
SO
2
reduction
requirements.
4.
Clarification
of
the
timing
requirements
for
NO
X
allowance
allocations
for
States
wishing
to
adopt
the
CAIR
model
NO
X
trading
rules
and
participate
in
the
EPA­
administered
NO
X
trading
programs.
The
proposed
rule
referenced
the
timing
provisions
in
the
model
trading
rules.
The
final
rule
spells
out
the
timing
requirements
and
modifies
them
to
allow
initial
allocations
in
3­
year
blocks,
rather
than
in
5­
year
blocks.
This
is
similar
to
the
approach
in
the
NO
X
SIP
Call
model
trading
rule,
which
provided
for
initial
allocations
in
3­
year
blocks.
States
that
choose
to
make
initial
allocations
in
blocks
longer
than
3
years
have
the
flexibility
to
do
so.
5.
Addition
of
flexibility
concerning
the
adoption
of
opt­
in
provisions
for
States
wishing
to
adopt
the
CAIR
model
NO
X
trading
rules
and
participate
in
the
EPA­
administered
NO
X
trading
programs.
Similar
provisions
are
added
to
§
51.124
with
regard
to
the
CAIR
model
SO
2
trading
rule.
6.
Elimination
of
provisions
in
the
proposed
regulatory
text
concerning
certain
States
identified
as
significantly
contributing
only
with
regard
to
ozone.
Ozone
season
NO
X
emission
reduction
requirements
are
addressed
for
all
States
significantly
contributing
with
regard
to
ozone
in
the
separate
provisions
for
such
requirements.
7.
Certain
definitions
are
clarified,
consistent
with
the
clarifications
in
definitions
or
other
provisions
(
e.
g.,
§
§
96.104
and
96.204)
in
the
CAIR
model
trading
rules.
For
example,
the
definition
of
"
utility
power
distribution
system"
is
revised
to
be
consistent
with
the
definition
in
the
CAIR
model
trading
rules
and
with
the
analogous
definition
of
"
power
distribution
system"
in
the
Acid
Rain
Program
regulations.

Changes
to
SO
2­
related
SIP
revision
requirements
in
§
51.124
Many
of
the
changes
in
the
final
§
51.124
from
the
proposed
regulatory
text
are
analogous
to
those
discussed
above
in
connection
with
changes
in
the
final
§
51.123.
In
addition,
a
revised
procedure
for
ensuring
that
excess
title
IV
allowances
are
retired
is
included
in
the
final
§
51.124.
The
procedure
in
the
final
rule
provides
States
more
flexibility
than
the
procedure
in
the
proposed
rule,
but
accomplishes
the
same
goals,
e.
g.,
of
preventing
disruption
of
the
title
IV
SO
2
allowance
market
and
preserving
the
title
IV
SO
2
cap­
and­
trade
system.
