Document ID: EPA-HQ-OAR-2003-0053-1290
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-04-22T04:00Z

Chapter
IV
edits:
Conservative
Baseline
&
NSR
Conservative
Baseline
[
Excerpt
from
Chp
IV.
Integration
with
Existing
CAA
Requirements]

p.
21
|
For
non­
EGU
sources
that
do
not
have
Part
75
monitoring
data
to
use
as
a
baseline,
a
historical
baseline
must
be
established
that
estimates
actual
emissions
in
a
way
that
matches
or
approaches
as
closely
as
possible
the
certainty
provided
by
the
Part
75
measured
data
for
EGUs.
In
the
absence
of
Part
75
measured
data,
EPA
proposes
that
States
be
required
to
estimate
historical
baseline
emissions
using
assumptions
that
conservatively
use
best
engineering
judgement
to
|
quantify
a
source's
or
|
source
category's
actual
emissions;
source­
specific
data
is
preferred
when
it
is
available.
In
this
case,
a
conservative
estimate
would
need
to
err
on
the
side
of
underestimating
baseline
emissions.
Because
the
substitute
emissions
reductions
are
estimated
by
subtracting
controlled
emissions
from
a
projected
baseline,
if
the
historical
baseline
overestimates
actual
emissions,
the
estimated
reductions
could
be
higher
than
the
actual
reductions
achieved.
To
achieve
a
conservative
baseline,
States
must
use
conservative
emission
factors
(
e.
g.,
emission
factors
at
the
low
end
of
a
range
when
EPA
guidance
presents
a
range)
or
the
State
must
provide
additional
information
that
shows
with
reasonable
confidence
that
another
value
is
more
appropriate
for
estimating
actual
emissions.
Other
monitoring
or
stack
testing
data
can
be
considered
but
care
22
p.
22
must
be
taken
not
to
overestimate
baselines.
If
a
production
or
utilization
factor
is
part
of
the
historical
baseline
emissions
calculation,
again,
a
low
(
i.
e.,
conservative)
number
must
be
used,
or
additional
data
must
be
provided.
Similarly,
if
a
control
efficiency
factor
and/
or
rule
effectiveness
factor
enters
into
the
estimate
of
historical
baseline
emissions,
it
must
be
realistic
and
supported
by
facts
or
analysis.
For
these
factors,
a
high
value
(
closer
to
100%
control
and
effectiveness)
is
conservative.
Once
the
historical
baseline
is
established
for
SO2
and/
or
NOx
emissions
from
the
substitute
sources,
the
second
step
is
to
project,
or
grow,
these
emissions
to
conditions
expected
in
2010
and
2015.
This
step
results
in
the
2010
and
2015
baseline
emissions
estimates.
This
step
should
be
done
with
state­
of­
the­
art
methods
for
projecting
the
source
or
source
category's
economic
output.
To
the
degree
available,
economic
forecasts
should
be
specific
to
the
State
and
county
where
the
source
is
located.
Where
changes
in
production
method,
materials,
fuels,
or
efficiency
are
expected
to
occur
between
the
baseline
year
and
2010
or
2015,
these
must
be
accounted
for
in
the
projected
2010
and
2015
baseline
emissions.
The
projection
must
also
account
for
any
adopted
regulations
that
will
affect
source
23
New
Source
Review
­

Add
a
new
section
"
E"
at
the
end
of
Chapter
IV
(
Integration
with
Existing
Clean
Air
Act
Requirements)

E.
Changes
in
New
Source
Review
applicability
For
any
EGU
in
a
state
with
a
SIP
revision
approved
pursuant
to
this
IAQR,
the
term
"
modification"
is
defined
as
follows:

The
term
`
modification'
means
any
physical
change
in,
or
change
in
the
method
of
operation
of,
an
affected
unit
that
increases
the
maximum
hourly
emissions
of
any
pollutant
regulated
under
this
Act
above
the
maximum
hourly
emissions
achievable
at
that
unit
during
the
five
years
prior
to
the
change
or
that
results
in
the
emission
of
any
pollutant
regulated
under
this
Act
and
not
previously
emitted,
provided
that
the
source
is
in
compliance
with
all
emission
and
permit
requirements.