1
MEMORANDUM
DATE:
February
19,
2004
SUBJECT:
Subcategories
for
the
Stationary
Reciprocating
Internal
Combustion
Engines
Final
Rule
FROM:
Tanya
Ali
Alpha­
Gamma
Technologies,
Inc.

TO:
Sims
Roy,
EPA
OAQPS
ESD
Combustion
Group
The
purpose
of
this
memorandum
is
to
present
the
subcategories
EPA
developed
for
the
stationary
reciprocating
internal
combustion
engines
(
RICE)
final
rule.
Section
112
of
the
Clean
Air
Act
as
amended
in
1990
(
CAA)
allows
the
EPA
to
establish
subcategories.
These
subcategories
are
based
on
technical
criteria
that
differentiate
sources
in
terms
of
technical
feasibility
or
applicability
of
emissions
control.

Background
On
December
19,
2002,
EPA
proposed
national
emission
standards
for
hazardous
air
pollutants
(
NESHAP)
for
stationary
RICE
(
67
FR
77830).
For
proposal,
EPA
developed
the
following
seven
subcategories:

°
2
stroke
lean
burn
(
2SLB)
stationary
RICE,
°
4
stroke
lean
burn
(
4SLB)
stationary
RICE,
°
4
stroke
rich
burn
(
4SRB)
stationary
RICE,
°
compression
ignition
(
CI)
stationary
RICE,
°
emergency
power/
limited
use
stationary
RICE,
°
stationary
RICE
that
combust
landfill
gas
or
digester
gas
as
their
primary
fuel,
and
°
stationary
RICE
with
a
manufacturer's
nameplate
rating
of
500
brake
horsepower
(
HP)
or
less.

The
rationale
leading
to
the
development
of
these
subcategories
was
presented
in
the
memorandum
entitled
"
Subcategorization
of
Stationary
Reciprocating
Internal
Combustion
Engines
for
the
Purpose
of
NESHAP"
available
from
EPA's
Edocket
Website
as
Document
ID
Number
OAR­
2002­
0059­
0066
(
A­
95­
35
II­
B­
43).
2
Subcategories
for
Final
Rule
Based
on
comments
received
on
the
proposed
rule
for
stationary
RICE,
EPA
has
made
some
revisions
to
the
subcategories
established
at
proposal,
however,
for
the
most
part,
the
subcategories
remain
unchanged.
The
following
sections
describe
the
subcategories
for
the
final
rule.

Landfill/
Digester
Gas
Stationary
RICE
In
the
proposed
rule,
EPA
established
a
subcategory
for
stationary
RICE
that
fire
landfill
gas
or
digester
gas
as
their
primary
fuel.
The
EPA
established
a
similar
subcategory
for
the
stationary
combustion
turbines
proposed
rule
(
68
FR
1888).
Comments
received
during
the
public
comment
period
stated
that
primary
fuel
was
not
defined
in
the
proposed
rule
for
stationary
RICE.
Comments
EPA
received
also
stated
that
the
final
RICE
rule
should
consider
exempting
any
RICE
using
landfill
gas.
Comments
indicated
that
a
diesel
engine
can
operate
at
a
landfill
in
a
dual­
fuel
mode
using
fuel
oil
and
landfill
gas.
Comments
further
noted
that
tests
have
shown
that
a
catalytic
converter
cannot
be
used
because
of
siloxanes
in
the
landfill
gas,
even
if
the
engine
operates
with
more
than
half
the
energy
being
supplied
by
the
liquid
fuel.
Comments
received
on
the
proposed
rule
for
stationary
combustion
turbines
stated
that
the
subcategory
for
landfill
and
digester
gas
fired
turbines
should
be
for
units
with
annual
landfill
and
digester
gas
consumption
10
percent
or
more
of
the
total
fuel
consumption
on
an
annual
basis,
which
is
similar
to
the
boiler
new
source
performance
standards
in
40
CFR
part
60,
subpart
Db.
The
EPA
adopted
the
language
suggested
by
comments
in
the
stationary
combustion
turbines
final
rule.

Based
on
the
above,
EPA
felt
it
was
appropriate
to
adjust
the
subcategory
and
has
defined
the
subcategory
as
follows
in
the
final
rule:

Stationary
RICE
that
combust
landfill
or
digester
gas
equivalent
to
10
percent
or
more
of
the
gross
heat
input
on
an
annual
basis.

For
additional
information
supporting
the
revision
of
this
subcategory,
please
refer
to
the
memorandum
entitled
"
Stationary
Combustion
Turbines
and
Reciprocating
Internal
Combustion
Engines
fired
with
Landfill
or
Digester
Gas"
(
Docket
ID
Nos.
OAR­
2002­
0059
and
A­
95­
35).

Emergency
Power
Stationary
RICE
At
proposal,
EPA
established
one
subcategory
for
emergency
power
and
limited
use
stationary
RICE.
This
subcategory
was
defined
as:

Emergency
power/
limited
use
stationary
RICE
means
any
stationary
RICE
that
operates
as
a
mechanical
or
electrical
power
source
when
the
primary
power
source
for
a
facility
has
been
rendered
inoperable
by
an
emergency
situation.
Examples
include
stationary
RICE
used
when
electric
power
is
interrupted,
3
stationary
RICE
used
to
pump
water
in
the
case
of
fire
or
flood,
etc.
Emergency
power/
limited
use
units
also
include
units
that
operate
less
than
50
hours
per
year
in
non­
emergency
situations,
including
certain
peaking
units
at
electric
facilities
and
stationary
RICE
at
industrial
facilities.

The
EPA
received
several
comments
on
the
emergency
power/
limited
use
subcategory
established
for
proposal.
In
general,
commenters
were
concerned
that
the
50
hours
per
year
provided
for
non­
emergency
use
was
not
even
sufficient
to
cover
periods
when
the
source
is
conducting
testing
and
maintenance
of
their
units.
Some
commenters
recommended
that
testing
and
maintenance
not
be
counted
towards
the
50
hours
per
year.
Some
commenters
stated
that
the
limited
use
definition
should
be
separated
from
the
emergency
power
definition
since
these
are
really
different
applications.
For
clarity,
some
commenters
recommended
that
these
definitions
be
separated
in
the
final
rule.
At
proposal,
EPA
solicited
comments
on
creating
a
subcategory
of
limited
use
stationary
RICE
with
capacity
utilization
of
10
percent
or
less
(
876
or
fewer
hours
of
annual
operation).
In
general,
industry
supported
the
creation
of
such
a
subcategory,
however,
State
and
environmental
agencies
were
generally
opposed
to
establishing
such
a
subcategory.

The
EPA
considered
all
comments
received
on
the
proposed
rule
and
has
decided
not
to
include
a
subcategory
of
limited
use
stationary
RICE
defined
as
those
with
capacity
utilization
of
10
percent
or
less.
Limited
use
stationary
RICE
with
annual
operation
of
876
hours
per
year
or
less
are
similar
to
other
units
that
are
equipped
with
add­
on
control
and
their
operation
during
certain
periods
does
not
preclude
them
from
being
equipped
with
add­
on
control.
Furthermore,
commenters
did
not
provide
any
information
that
supports
establishing
such
a
subcategory,
nor
did
they
provide
significant
data
showing
that
engines
operating
10
percent
or
less
are
unable
to
take
step
similar
to
other
stationary
RICE
to
reduce
emissions
of
HAP.
The
EPA
therefore
felt
that
it
was
not
appropriate
to
establish
a
subcategory
of
limited
use
units
with
capacity
utilization
of
10
percent
or
less.

Based
on
the
comments
received,
EPA
understands
that
50
hours
per
year
might
not
even
cover
periods
of
testing
and
maintenance
and
is
not
a
sufficient
amount
to
serve
a
useful
purpose.
The
EPA
has
therefore
increased
the
amount
to
100
hours
per
year
for
limited
use
and
feels
that
this
amount
is
still
justified
in
the
sense
that
usage
for
less
than
100
hours
per
year
is
clearly
exceptional
and
these
engines
would
have
technical
and
usage
concerns
similar
to
emergency
engines.
These
engines
are
categorically
different
from
other
engines
in
that
they
are
only
used
in
truly
unique
situations.
The
final
rule
defines
limited
use
stationary
RICE
as
follows:

Limited
use
stationary
RICE
means
any
stationary
RICE
that
operates
less
than
100
hours
per
year.

The
EPA
feels
that
it
is
appropriate
to
separate
the
definitions
of
emergency
power
and
limited
use
stationary
RICE.
It
was
clear
from
multiple
comments
received
on
the
proposal
that
the
combination
of
these
two
applications
in
one
definition
created
4
confusion
within
the
regulated
community.
The
EPA
has
established
separate
subcategories
and
definitions
for
emergency
power
and
limited
use
stationary
RICE
in
the
final
rule.
The
definition
of
limited
use
stationary
RICE
was
provided
above.
As
previously
indicated
in
this
memorandum,
the
rationale
supporting
the
development
of
subcategories
for
the
proposal
was
discussed
in
an
earlier
memorandum
submitted
to
the
docket.
A
limited
use
subcategory
was
developed
to
account
for
several
factors.
One
main
reason
for
establishing
a
limited
use
subcategory
was
that
no
known
limited
use
units
are
operating
with
emission
controls
that
reduce
HAP
emissions.
Emission
control
technologies
which
reduce
HAP
emissions
from
stationary
RICE
have
not
been
applied
to
stationary
RICE
which
operate
exclusively
as
limited
use
units.

Emergency
power
stationary
RICE
are
not
limited
to
a
specific
number
of
hours
of
operation
for
true
emergency
use.
In
addition,
testing
and
maintenance
for
readiness
purposes
have
been
included
in
the
definition
of
emergency
power
stationary
RICE
in
the
final
rule
as
long
as
they
are
within
the
limits
recommended
by
the
engine
manufacturer
or
other
entity
such
as
an
insurance
company.
Finally,
emergency
stationary
RICE
may
also
operate
an
additional
50
hours
per
year
in
non­
emergency
situations.
The
final
rule
defines
emergency
stationary
RICE
as
follows:

Emergency
stationary
RICE
means
any
stationary
RICE
that
operates
in
an
emergency
situation.
Examples
include
stationary
RICE
used
to
produce
power
for
critical
networks
or
equipment
(
including
power
supplied
to
portions
of
a
facility)
when
electric
power
from
the
local
utility
is
interrupted,
or
stationary
RICE
used
to
pump
water
in
the
case
of
fire
or
flood,
etc.
Emergency
stationary
RICE
may
be
operated
for
the
purpose
of
maintenance
checks
and
readiness
testing,
provided
that
the
tests
are
recommended
by
the
manufacturer,
the
vendor,
or
the
insurance
company
associated
with
the
engine.
Required
testing
of
such
units
should
be
minimized,
but
there
is
no
time
limit
on
the
use
of
emergency
stationary
RICE
in
emergency
situations
and
for
routine
testing
and
maintenance.
Emergency
stationary
RICE
may
also
operate
an
additional
50
hours
per
year
in
non­
emergency
situations.

2SLB,
4SLB,
4SRB,
and
CI
Stationary
RICE
The
subcategories
of
2SLB,
4SLB,
4SRB,
and
CI
stationary
RICE
have
not
been
modified
since
the
proposal
and
remain
unchanged
in
the
final
rule.

Stationary
RICE

500
Brake
HP
The
EPA
made
a
minor
adjustment
to
the
subcategory
of
stationary
RICE
with
a
manufacturer's
nameplate
rating
of
500
brake
HP
or
less.
Comments
received
urged
EPA
to
express
the
size
threshold
in
site­
rated
HP
rather
than
manufacturer's
nameplate
rating.
The
EPA
felt
the
justifications
the
commenters
provided
were
valid.
The
EPA
believes
that
relying
on
the
manufacturer's
nameplate
rating
for
the
size
applicability
threshold
is
not
appropriate
as
such
a
rating
may
not
be
representative
of
the
capacity
of
the
engine
on­
site.
The
EPA
has
therefore
revised
the
subcategory
in
5
the
final
rule.
The
subcategory
includes
stationary
RICE
with
a
site­
rating
of
500
brake
HP
or
less.

The
final
rule
does
not
apply
to
stationary
RICE
with
a
site­
rating
of
500
brake
HP
or
less.
The
EPA
feels
that
this
subcategory
of
stationary
RICE
is
likely
to
be
more
similar
to
stationary
RICE
located
at
area
sources
than
to
stationary
RICE
located
at
major
sources.
Thus,
EPA
plans
to
include
this
subcategory
of
stationary
RICE
in
its
considerations
to
develop
regulations
for
stationary
RICE
located
at
area
sources,
which
will
be
addressed
in
a
later
rule.

Conclusion
Based
on
the
above
discussion,
eight
subcategories
of
stationary
RICE
have
been
established
for
the
final
rule.
The
subcategories
are:

°
2SLB
stationary
RICE,
°
4SLB
stationary
RICE,
°
4SRB
stationary
RICE,
°
CI
stationary
RICE,
°
emergency
power
stationary
RICE,
°
limited
use
stationary
RICE,
°
stationary
RICE
that
combust
landfill
or
digester
gas
equivalent
to
10
percent
or
more
of
the
gross
heat
input
on
an
annual
basis,
and
°
stationary
RICE
with
a
site­
rating
of
500
brake
HP
or
less.
