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OAR Box 1781 

Prepped by Ollie Stewart 

Document Number: 

32) 11-1-24 

Docket Number: 

A-90-37 

Printed 10/29/2008 10:46:19 AM Sheet 32 of 142 
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New York State Department of Environmental Conservation 

50 Wolf Road, Albany, New York 12233 

April 1, 1991 

MEMORANDU M 

TO: 

Thomas C Jorllng 

Commissioner 

bi-; 

Regional Air Pollution Control _Engirie^erjr/\/;,,. MOJ^: 

Bureau Directors 

Section Chiefs 

FROM: Mr. Allen (Originator: R. Parker) 

SUBJECT: Gas Turbine NOx Policy. 91-AIR-39 

Policy 

NYSDEC policy regarding NOx control for gas turbines is as follows. 

As ;always, the Best Available Control Technology (BACT) for 

projects subject to review under the Prevention of Significant 

Deterioration (PSD) regulation, is determined case-by-case. 

However, as of this date, BACT level of control for NOx emissions 

from gas turbines is generally regarded as 9 ppmv (dry, corrected 

to 15% 02) when firing natural gas and 18 ppmv (dry, corrected to 

15% 02) when firing distillate oil. . 

If oil is used solely as a backup fuel in a gas turbine project 

using Selective Catalytic Reduction (SCR) the following also 

applies. In recognition of the potential problems of increased 

particulate and ammonium bisulfate formation during oil firing, NOx 

emission levels up to 3 0 ppm can be considered BACT if there is a 

corresponding decrease in the ammonia slip limit. For a 30 ppm NOx 

limit during oil firing, ammonia slip should be limited to 3 ppmv 

(dry, corrected to 15% 02) . 

The above BACT guideline limits assume that NOx emissions are being 

controlled from 25 ppm on gas and 42 ppm on oil (via combustion 

modifications) down to 9 ppm/18 ppm, which is currently achievable 

with SCR NOx control. 

Project applicants may attempt to demonstrate that 9 ppm/18 ppm is 

not BACT for a particular project. However, the applicant must 

demonstrate what unique circumstances preclude this level of 

control for the project as compared to other projects which are 

proposing or achieving 9 ppm/18 ppm. NYSDEC will review these 

demonstrations case-by-case. 
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Applicabilitv 

This policy applies to all gas turbine projects subject to PSD 

review!' Since it is EPA's policy that BACT determinations are not 

final until the final PSD permit is issued, this policy applies to 

all PSD projects which have not received a final permit from NYSDEC 

* as of this date. 

All non-PSD gas turbine projects for which NYSDEC has received 

applications prior to 11/8/90 are not affected by this policy. 

However, all non-PSD gas turbine projects for which NYSDEC has not 

received an application as of 11/8/90 may be subject to this policy 

pursuant to the State Environmental Quality Review Act (6 NYCRR 

Part 617). The applicability of this policy pursuant to SEQR will 

be determined on a case-by-case basis. 

Background 

There are a large number of gas turbine projects being proposed 

throughout the Northeast at this time. New York State alone has 20 

applications pending for gas turbine projects. This may be the 

result of several factors including an apparent abundance of 

affordable natural gas, financial incentives for cogeneration 

facilities, and the development of a bidding system for utilities 

to meet increasing power demand. Regardless of the reasons, due to 

the large number of projects, NYSDEC and all of the NESCAUM states 

are concerned about the potential cumulative impacts of NOx 

emissions from these facilities with regard to the Northeast ozone 

non-attainment ..and. acid deposition problems. In light ;of theseproblems, NESCAUM has developed a policy regarding gas turbine' 

emissions which calls for NOx emission levels similar to those 

included in this policy. 

For an 80 MW single gas turbine project, approximately 300 

tons/year of potential NOx emissions can be removed by reducing NOx 

emissions from 25 ppm gas/42 ppm oil down to 9 ppm gas/18 ppm oil. 

300 tons/year of NOx emissions may not significantly contribute to 

the Northeast ozone and acid deposition problems alone. However, 

the cumulative potential NOx reductions from all of the gas 

turbines combined is significant. In New York State, cumulative 

NOx reductions for the 20 proposed projects (1720 MW) exceeds 6000 

tons/year. 

There are several gas turbine projects in New York State and in the 

Northeast that are proposing the installation of SCR control. A 

list of these projects can be found in attachment one. It is 

apparent that SCR technology is a technically feasible method of 

obtaining 'significant NOx reductions. Since significant NOx 

emissions will be achieved at some facilities, the same degree of 

control should apply to similar new projects. 
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Applicants must use the Top Down approach in demonstrating that 9 

ppm gas and 18 ppm oil is beyond BACT. In doing so, in order to 

rule out a control option based on economics, the applicant must 

present why the cost of installing the control for their project is 

significantly higher than the cost for other projects offering the 

same controls. This approach is supported in EPA's 

draft written guidance entitled "TOP Down" Best Available Control 

Technology Guidance Document dated March 15, 1990. A copy of this 

document may be obtained from the Bureau of Source Control. 

As an example, consider a simple cycle gas turbine project that 

will be used to provide peak power. It is technically feasible to 

achieve 9 ppm on gas and 18 ppm on oil by installing SCR. However, 

this would require cooling the exhaust gas prior to entering the 

SCR. After reviewing the list of cogeneration projects in 

attachment one, it is evident that this would be an expense unique 

to this type of project. Further, a peaking unit is often limited 

in the annual hours of operation. This limit reduces the potential 

annual NOx reductions, which in turn increase the cost/ton of NOx 

removal by SCR. An applicant could present these factors in a Top 

Down BACT analysis to demonstrate that SCR in this case is beyond 

BACT. 

Future Disposition. 

The technology for controlling NOx emissions from gas turbines is 

rapidly evolving. This policy reflects the situation as it exists 

now. However future developments such as "Dry-Low NOx" combustion 

may cause changes to this policy. As these developments occur, the 

Bureau of Source Control will reconsider and modify as necessary 

this policy. 

cc: Regional Directors of Environmental Quality Engineering 
Gas Turbine Projects in the Northeast 

Permitted vith or Proposing SCR NOx Control 

2/22/91 

Project Name State 

Dunkirk Cogen 

Hadson Power 

East Syracuse 

KEAC Partners 

Indeck Olean 

Sithe/Alcoa 

Indeck Corinth 

Selkirk Cogen 

Wallkill IPP 

Guilderland 

Pawtucket Power 

Cogen Technologies 

Ocean State Power 

MASSPOWER 

Altresco 

Ventron 

CNG Lakewood 

Arrowhead Cogen 

NY 

NY 

NY 

NY 

NY 

NY 

NY 

NY 

NY 

NY 

RI 

NJ 

RI 

MA 

MA 

MA 

NJ 

VT 

Size 

50 

80 

100 

145 

79 

79 

100 

252 

150 

230 

60 

165 

500 

246 

160 

28 

210 

25 

Back-up 

Oil Use 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

Yes 

NOx limit 

Gas/Oil 

9 ppm/48 ppm 

9 ppm/65 ppm 

9 ppm/30 ppm 

9 ppm/18 ppm 

9 ppm/18 ppm 

9 ppm/18 ppm 

9 ppm/18 ppm 

9 ppm/19 ppm 

9 ppm/30 ppm 

9 ppm/30 ppm 

9 ppm/18 ppm 

15 ppm/65 ppm 

9 ppm/42 ppm 

9 ppm/18 ppm 

9 ppm/18 ppm 

9 ppm/9 ppm 

9 ppm/21 ppm 

9 ppm/ 

Status 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Proposed 

Permitted 

Operating 

Permitted 

Permitted 

Operating 

Permitted 

Proposed 

Permitted 

••-/•fcS** 1 - ' ' . 

Attachment (l)