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THE CORRESPONDENCE OR PROVIDED THE RESPONSE.
4.17
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
JUN 24 1981
OFFICE OF ENFORCEMENT
Mr. Amasjit S. Gill
General Electric - Gas Turbine Division
One River Road
Schenectady, New York 12345
Dear Mr. Gill:
This is to respond to your letter of May 19, 1981, requesting a
determination of the applicability of NSPS and PSD to stationary gas
turbines converting from middle distillates to natural gas.
The information presented in your letter indicated that NOx and SO2
emissions will decrease after the conversion to natural gas and
hydrocarbons, CO and particulate emissions will either remain the same or
decrease. As you correctly pointed out in your letter, the NSPS would only
apply if there is an increase in emissions of a pollutant to which the
standard applies. The NSPS for gas turbines applies only to NOx and SO2
emissions. Since the conversion from middle distillate fuel to natural gas
for the turbines in question will cause a decrease in NOx and SO2 emissions,
it is not considered a modification as defined in 40 CFR 60.14(a). The
turbines however, could be subject to the NSPS if the conversion falls under
the definition of reconstruction (See 40 CFR 60.15).
PSD review would apply to a proposed modification at an existing major
stationary source if it would cause a significant net increase in actual
emissions of any regulated pollutant. In the case of the gas turbine
conversions outlined in your letter, PSD applicability is determined by
evaluating any change in emissions rates caused by the conversions. The
data contained in your letter indicate that the emission rates after the
conversion will either remain constant or decrease. Actual emissions could
increase only if there is an increase in the production rate or hours of
operation, both of which are specifically exempt from PSD review. (See 40
CFR 52.21(b) (2) (iii) (f)). Therefore, since there will not be any
increase in emission rates or any creditable increases in actual emissions,
the conversion of the gas turbines will not be subject to PSD review.
If you have any questions concerning this determination please contact
Janet Farella of my staff at 202-755-2564.
Sincerely yours,
Edward E. Reich, Director
Division of Stationary
Source Enforcement
cc: Peter Wyckoff
Mike Trutna
GENERAL ELECTRIC | | |
| | |
GENERAL ELECTRIC COMPANY, ONE RIVER ROAD, | | |
SCHENECTADY, NEW YORK 12345 | | |
TELEPHONE | | |
(518)385-4131 | | |
| |GAS TURBINE DIVISION |
| |OPERATIONAL PLANNING |
| | |
Copy: Don R. Goodwin, EPA
Research Triangle Park,
NC 27711
May 19, 1981
Mr. Edward Reich, Director
Division of Stationary Source Enforcement
Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
Dear Mr. Reich:
Stationary Gas Turbines
Converting from Distillate to Natural Gas
The Economic Regulatory Administration of the Department of Energy grants
temporary public interest exemptions, from the prohibitions of the Fuel Use
Act of 1978, to burn natural gas where such use displaces the use of middle
distillates, thereby decreasing our reliance on imported oil.
Existing gas turbines, which do not have built-in dual fuel capability,
install new combustion hardware so that they can burn natural gas instead of
middle distillates. The concern aries whether such a conversion would be
classified a "modification" or "major modification" and, therefore, subject
the gas turbine to the New Source Performance Standards (NSPS) or a
Prevention of Significant Deterioration (PSD) review.
MODIFIED
The definition of modification is provided in 40 CFR 60
as:
60.14 (a) "Except as provided under paragraphs (e) and (f) of this
section, any physical or operational change to any existing
facility which results in an increase in the emission rate to
the atmosphere of any pollutant to which a standard applies
shall be considered a modification within the meaning of
Section III of the Act
60.2 "`Standard' means a standard of performance proposed or
promulgated under this part."
GENERAL ELECTRIC
Page 2
NEW SOURCE PERFORMANCE STANDARDS (NSPS)
Hydrocarbons, carbon monoxide and particulates are specifically
excluded from the NSPS promulgated on Sept. 10, 1979. Justification
for the exclusion was provided in the Oct 3, 1977 Federal Register on
page 53783.
"HC and CO emissions from stationary gas turbines operating at
peak load are relatively low because the higher the percentage of
peak load at which a turbine operates, the more efficient the
combustion of the fuel. Gas turbines normally operate at 80 to 100
percent of peak load with HC emissions averaging less than 50 ppm
and CO emissions averaging less than 500 ppm at 15 percent oxygen.
HC and CO emissions from stationary gas turbines, therefore, were
not selected for control by standards of performance."
"Particulate emissions from stationary gas turbines depend on the
ash content of the fuel and are minimal. Consequently,
particulate emissions from stationary gas turbines were not
selected for control by standards of performance."
Since there is no standard for CO, unburned hydrocarbons and
particulates under NSPS for stationary gas turbines, NSPS would not
apply even if there was an increase in the emission rate of these three
pollutants. As shown in the attached four tables, NOx and SO2
decrease, and CO, unburned hydrocarbons and particulates remain
unchanged or decrease.
PREVENTION OF SIGNIFICANT DETERIORATION (PSD)
PSD review would apply if the emissions increase by amounts greater
than de minimis levels. De minimis levels, shown on page 52709 in the
August 7, 1980 Federal Register, are:
| Tons/Year | Equivalent lbs/hour (8760 hours/year) |
Carbon Monoxide | 100 | 22.83 |
Nitrogen Oxides | 40 | 9.13 |
Sulfur Dioxide | 40 | 9.13 |
Particulates | 25 | 5.70 |
Volatile Organic Compounds | 40 | 9.13 |
For those machines which are not restricted to a specific number of hours of
operation per year by an enforceable permit condition, allowable emissions
would be the hourly emission rate multiplied by 8760 hours per year. Then,
for PSD review purposes, net emissions increases should be evaluated against
these allowable emissions to see if de minimis levels are exceeded.
GENERAL ELECTRIC
Page 3
PSD (cont'd)
As can be seen from the attached four tables which provide uncontrolled
emission rates for four GE gas turbines, the hourly emissions rates
decrease for NOx and SO2 and remain unchanged or decrease for CO,
unburned hydrocarbons and particulates when the fuel is switched from
distillate to natural gas.
Therefore, these four gas turbine models would not require a PSD review
when the capability to burn natural gas is added and the fuel is
switched from distillate to natural gas, and "allowable" emissions, as
opposed actual emissions, are not exceeded on an annual basis.
Your official concurrence with our interpretation is requested at your
earliest convenience.
Sincerely,
A.S Gill, Environmental/Regulatory Planner
/eb
Attach.
GENERAL ELECTRIC
P G 7 1 0 1 E
FUEL -----> | NATURAL GAS | DISTILLATE |
LOAD -----> | BASE | PEAK | BASE | PEAK |
Output, | kW | 74,400 | 80,500 | 72,900 | 78,800 |
Heat Rate (LHV), | Btu/kWh | 10,690 | 10,640 | 10,790 | 10,750 |
Fuel Consump.(LHV) 1,000,000 Btu/hr | | 795.3 | 856.5 | 786.6 | 847.1 |
NOx as NO2, | lbs/hr | 450 | 535 | 790 | 970 |
SOx as SO2, [see footnote *] | lbs/hr | 0 | 0 | 254 | 275 |
Particulates, | lbs/hr | < 28 | < 30 | 28 | 30 |
Hydrocarbons, (as CH4), | lbs/hr | < 12 | < 12 | 12 | 12 |
CO, | lbs/hr | < 21 | < 21 | 21 | 21 |
[footnote *] Distillate Fuel with 0.3% Sulfur by Weight,
Natural Gas Fuel Containing no Sulfur.
The results are based on field and combustion laboratory test data from
the same or similar machines and combustion systems, correlated to
provide a coherent body of emissions data. The data presented are for
operation at ISO conditions.
GENERAL ELECTRIC
P G 7 8 5 1
FUEL -----> | NATURAL GAS | DISTILLATE |
LOAD -----> | BASE | PEAK | BASE | PEAK |
Output, | kW | 61,300 | 67,700 | 60,000 | 66,300 |
Heat Rate (LHV), | Btu/kWh | 11,000 | 10,920 | 11,130 | 11,030 |
Fuel Consump.(LHV) 1,000,000 Btu/hr | | 674.3 | 739.3 | 667.8 | 731.3 |
NOx as NO2, | lbs/hr | 325 | 405 | 510 | 640 |
SOx as SO2, [see footnote *] | lbs/hr | 0 | 0 | 216 | 237 |
Particulates, | lbs/hr | < 24 | < 26 | 24 | 26 |
Hydrocarbons, (as CH4), | lbs/hr | < 11 | < 11 | 11 | 11 |
CO, | lbs/hr | < 19 | < 19 | 19 | 19 |
[footnote *] Distillate Fuel with 0.3% Sulfur by Weight,
Natural Gas Fuel Containing no Sulfur.
The results are based on field and combustion laboratory test data from
the same or similar machines and combustion systems, correlated to
provide a coherent body of emissions data. The data presented are for
operation at ISO conditions.
GENERAL ELECTRIC
P G 6 4 4 1 A
FUEL -----> | NATURAL GAS | DISTILLATE |
LOAD -----> | BASE | PEAK | BASE | PEAK |
Output, | kW | 31,750 | 34,750 | 31,100 | 34,000 |
Heat Rate (LHV), | Btu/kWh | 11,280 | 11,210 | 11,380 | 11,310 |
Fuel Consump.(LHV) 1,000,000 Btu/hr | | 358.1 | 389.5 | 353.9 | 384.5 |
NOx as NO2, | lbs/hr | 185 | 220 | 325 | 385 |
SOx as SO2, [see footnote *] | lbs/hr | 0 | 0 | 115 | 125 |
Particulates, | lbs/hr | < 13 | < 14 | 13 | 14 |
Hydrocarbons, (as CH4), | lbs/hr | < 6 | < 6 | 6 | 6 |
CO, | lbs/hr | <11 | < 11 | 11 | 11 |
[footnote *] Distillate Fuel with 0.3% Sulfur by Weight,
Natural Gas Fuel Containing no Sulfur.
The results are based on field and combustion laboratory test data from
the same or similar machines and combustion systems, correlated to
provide a coherent body of emissions data. The data presented are for
operation at ISO conditions.
GENERAL ELECTRIC
P G 7 1 0 1 E
FUEL -----> | NATURAL GAS | DISTILLATE |
LOAD -----> | BASE | PEAK | BASE | PEAK |
Output, | kW | 24,620 | 26,600 | 24,110 | 26,050 |
Heat Rate (LHV), | Btu/kWh | 12,300 | 12,200 | 12,450 | 12,340 |
Fuel Consump.(LHV) 1,000,000 Btu/hr | | 302.8 | 324.5 | 300.2 | 321.5 |
NOx as NO2, | lbs/hr | 140 | 155 | 200 | 225 |
SOx as SO2, [see footnote *] | lbs/hr | 0 | 0 | 97 | 104 |
Particulates, | lbs/hr | < 11 | < 11 | 11 | 11 |
Hydrocarbons, (as CH4), | lbs/hr | < 5 | < 5 | 5 | 5 |
CO, | lbs/hr | < 10 | < 10 | 10 | 10 |
[footnote *] Distillate Fuel with 0.3% Sulfur by Weight,
Natural Gas Fuel Containing no Sulfur.
The results are based on field and combustion laboratory test data from
the same or similar machines and combustion systems, correlated to
provide a coherent body of emissions data. The data presented are for
operation at ISO conditions. |