Public Service of New Hampshire 

Schiller Station 

400 Gosling Road, Portsmouth, NH 

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A. Introduction 

Final NOx RACT ORDER 

ARD-06-001 

August 4, 2006 

This NOx RACT Order is issued by the New Hampshire Department of Environmental Services, 

Air Resources Division, to Public Service ofNew Hampshire pursuant to RSA 125-C. 

B. Parties 

1. The New Hampshire Department of Environmental Services, Air Resources Division 

("DES"), is a duly constituted administrative agency of the State of New Hampshire having 

its principal offices at 29 Hazen Drive, Concord, NH 03302-0095, telephone number (603) 

271-1370. 

2. Public Service of New Hampshire (PSNH), a subsidiary of Northeast Utilities, is a New 

Hampshire Corporation, having a mailing address of 780 North Commercial Street, 

Manchester, NH 03101. 

C. Statements of Fact and Law 

1. PSNH operates the Schiller Station Power Facility (Schiller Station) located at 400 Gosling 

Road in Portsmouth, NH. 

2. Schiller Station is a 153 megawatt fossil fuel fired electric generating facility, owned and 

operated by PSNH. The power generating equipment is comprised of three utility boilers 

(Units #4, 5, and 6), one combustion turbine operating as a load shaving unit, and an 

emergency generator. 

3. On January 30, 2004, PSNH applied for a Temporary Permit to replace the Unit #5 coal-fired 

boiler with a new 50 megawatt utility boiler and a secondary coal crusher at Schiller Station. 

The new utility boiler ("NWPP Boiler") will be a circulating fluidized bed (CFB) design and 

will be capable of combusting wood or coal. The NWPP Boiler will utilize the Unit #5 

generator and turbine. To preheat the furnace fluidized bed material prior to combusting the 

solid fuel, a natural gas-fired burner system will be used during startup. The startup burner 

system consists of one natural gas-fired duct burner. 
Public Service of New Hampshire 

ARD-06-001 

August 4, 2006 

Page 2 o(4 

4. Effective May 20, 1994, DES adopted New Hampshire Administrative Rule PART Env-A 

1211 NITROGEN OXIDES (NOx). Effective October 31, 2002, DES revised and adopted 

New Hampshire Administrative Rule PART Env-A 1211 NITROGEN OXIDES (NOx). 

5. Env-A 1211.03 establishes NOx emission limitations for specific types of utility boilers. 

Env-A 1211.03 does not establish emission limitations for CFB type boilers; therefore, 

PSNH was required to submit a request for Alternative RACT Emission Limits pursuant to 

Env-A 1211.15. 

6. On May 28, 2004, PSNH submitted a request for alternative RACT emission limit pursuant 

to Env-A 1211.15 

7. Pursuant to Env-A 1211.15(c)(l), PSNH conducted a study of the technological and 

economic feasibility of NOx control techniques, including low NOx burners, overfire air, 

flue gas recirculation, natural gas reburn, burners out of service, use of alternative fuels, 

selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). PSNH 

proposes the use of the circulating fluidized bed technology, which is recognized as a low 

emission, advanced solid fuel combustion technology. The formation of NOx in the CFB 

boiler is reduced as a result of the low combustion temperatures and low excess air within the 

fluidized bed. While both natural gas rebum and flue gas recirculation are theoretically 

technically feasible for wood and oil fired boilers, the CFB boiler technology is not designed 

to utilize such methods of NOx reduction. The use of low-NOx burners and burners out of 

service are not technically feasible as NOx control options for the proposed CFB boiler. The 

use of alternative fuels is also not an option for NOx control from the boiler. 

8. PSNH contends that the only two technically feasible control techniques available for the 

CFB are SCR and SNCR. PSNH concluded that SCR would be economically infeasible 

because the high particulate loading in the gas stream would require increased capital, 

operating and maintenance costs to pretreat the particulate upstream of the SCR. The only 

viable NOx control technique is SNCR because it can operate effectively with a gas stream 

with high particulate loading. 

9. PSNH proposes to use an SNCR system where urea will be injected into the boiler furnace, 

where it is converted to ammonia. The NOx will react with the ammonia and form nitrogen 

gas and water. 

10. Although PSNH did not specifically address the use of ERCs or DERs as an em1sswn 

reduction strategy, it is an economically viable option. However, the use of a control 

technique, such as SNCR, will result in a greater overall reduction in NOx. 

11. In PSNH's Request for Alternative RACT Emission Limits, PSNH proposes to use 

circulating fluidized bed boiler technology with SNCR resulting in a NOx emission factor of 

0.075 lb!MMBtu. 
Public Service of New Hampshire 

ARD-06-001 

D. Order 

August 4, 2006 

Page 3 of4 

Based upon the above findings and determinations, DES hereby orders PSNH Schiller Station as 

follows: 

1. Install and operate the CFB boiler. 

2. Install and operate the SNCR as necessary to comply with the NOx emission rate when the 

CFB boiler is in operation. 

3. Comply with a 0.075 lbiMMBtu NOx emission rate for the CFB boiler. 

4. Conduct initial performance tests in accordance with Env-A 802 and 803 within 60 days of 

achieving the maximum production rate, but no later than 180 days from start-up (first firing 

of solid fuel). 

5. Use the continuous emissions monitoring systems to determine continuous compliance with 

the NOx emission rate. 

6. Continue to comply with the NOx RACT Order ARD-98-001 Conditions D.l.c. and D.l.d., 

i.e., non-ozone season NOx cap of 8,208 tons and ozone season NOx cap of 3, 727 tons for 

the combined NOx emissions from MK1, MK2, NTI, SR4, SR5, and SR6. 

7. Comply with the recordkeeping and reporting requirements ofEnv-A 900. 

Please address any correspondence and communication in reference to this Order to the 

following: 

Douglas C. Laughton 

NHDES, Air Resources Division 

Bureau of Permitting & Environmental Health 

29 Hazen Drive 

P.O. Box 95 

Concord, NH 03302-0095 

(603) 271-!370 

Robert R. Scott, Director 

Department of Environmental Services 

Air Resources Division 
Public Service of New Hampshire 

ARD-06-001 

cc: Timothy Drew, PIP Office 

David Conroy, US EPA 

Town Selectmen, Portsmouth 

RRS/dcl 

Final NWPP NOx RACT Order 

August 4, 2006 

August 4, 2006 

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