UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: December 1, 2009

SUBJECT: Technical Support Document for Delaware’s Amendment to Regulation No. 1146 

– Electric Generating Unit Multi-Pollutant Regulation

FROM: Irene Shandruk, Environmental Scientist

Office of Air Program Planning

TO: File

/s/

THRU: Cristina Fernandez, Associate Office Director

Office of Air Program Planning

A. BACKGROUND: 

On November 16, 2006, the Delaware Department of Natural Resources and Environmental 

Control (DNREC) submitted a revision to the Delaware State Implementation Plan (SIP). This 

SIP revision pertained to a new regulation, Regulation No. 1146 – Electric Generating Unit 

(EGU) Multi-Pollutant Regulation. The regulation was adopted in order to impose lower 

emissions limits of nitrogen oxides (NOx), sulfur dioxide (SO2) and mercury in order to help 

Delaware attain and maintain the national ambient air quality standards (NAAQS) for ozone and 

fine particulate matter (PM2.5), as well as to assist Delaware in achieving the emissions 

reductions needed to support the State’s 8-hour ozone reasonable further progress plan (RFP) for 

NOx. EPA approved the SIP revision on August 28, 2008 (73 FR 50723).

On October 7, 2009, EPA received a SIP revision for this rule, dated September 24, 2009. The 

revision is an amendment to Regulation No. 1146 of Delaware’s Administrative Code, and it 

modifies the SO2 mass emissions limit associated with Conectiv Edge Moor Unit 5 (as 

constrained in Regulation 1146’s Table 5-1) from 2,427 tons per year to 4,600 tons per year, 

beginning in calendar year 2009. No other changes were made to Regulation 1146. The 

effective date of the state level revision was October 10, 2009.

B. EPA REQUIREMENTS:

In 1998, the Environmental Protection Agency (EPA) issued the NOx SIP Call to reduce air 

emissions of NOx, which is a precursor to ozone that is subject to the NAAQS. The NOx SIP 

Call allowed NOx emissions trading, which allowed sources of NOx emissions an alternative to 
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investing in pollution control equipment. Instead of investing in pollution control equipment, the 

sources could purchase emission allowances.

In 2005, EPA issued the Clean Air Interstate Rule (CAIR) to further regulate NOx and SO2

emissions. CAIR also allowed emissions trading as an alternative to actual emission reductions 

from a source. EPA believed that the state caps set in CAIR represented the appropriate amount 

of cost-effective emissions reductions required to prevent significant contribution to 

nonattainment through transport of emissions to downwind ozone and PM2.5 nonattainment areas. 

However, States had flexibility in the design of NOx allocation schemes. Delaware believed 

that tighter caps on these sources were a necessary component of its plan for attainment of the 

NAAQS. Regulation 1146 supplemented the CAIR program by setting “hard” NOx and SO2

emissions caps that could not be exceeded for affected facilities. These units, however, were still 

subject to all of the EPA’s CAIR requirements, including its allowance allocation and cap-andtrade provisions, independent of this regulation. Thus, the units subject to Regulation 1146 were 

required to meet the cap set by this regulation independent of any compliance provisions of the 

CAIR program.

C. STATE SUBMITTAL:

Originally submitted to the EPA on November 16, 2006, Regulation No. 1146 established NOx 

and SO2 emission limits to achieve reductions from Delaware’s large EGUs. 

This multi-pollutant regulation impacts any owner or operator of a coal or residual oil fired 

power plant 25 megawatts (MW) and greater in size, specifically the Conective Delmarva 

Generating, Inc.’s Edge Moor Generating Station Units 3, 4 and 5; City of Dover’s McKee Run 

Generating Station Unit 3; and NRG Energy, Inc.’s Indian River Generating Station Units 1, 2, 3 

and 4. 

The following table identifies the units affected by this regulation and the annual SO2 mass 

emissions limits for each:

Facility Unit County Primary Fuel Annual SO2

Mass Emissions Limits (tons)

Edge Moor 3 New Castle Coal 1391

Edge Moor 4 New Castle Coal 2410

Edge Moor 5 New Castle Residual Oil 2427

Indian River 1 Sussex Coal 1082

Indian River 2 Sussex Coal 1130

Indian River 3 Sussex Coal 1759

Indian River 4 Sussex Coal 3657

McKee Run 3 Kent Residual Oil 439
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On October 7, 2009, EPA received an amendment to this regulation modifying the SO2 mass 

emissions limit associated with Conectiv Edge Moor Unit 5, located in New Castle County, 

Delaware, from 2,427 to 4,600 tons per year. Since this revision is only associated with the SO2

emissions limit, NOx will not be discussed here. 

This SIP revision was the result of a litigation settlement agreement between Conectiv Delmarva 

Generating, Inc. and the Department of Natural Resources and Environmental Control in 

December 2008. Conectiv had filed an appeal challenging the regulation for their Edge Moor 5 

facility. The argument was that the emissions limit of 2,427 tons per year limited the facility

from operating in extreme circumstances when failure at other production units would require 

them to exceed that limit in order to supply the needed electricity. The limit of 4,600 tons per 

year was determined to be an adequate limit after an analysis of the facility’s history of operation 

and the estimate of future operations using the low sulfur (0.5%) residual fuel to generate 

electricity at the 446 megawatt oil-fired steam generating unit. Currently, the facility operates at 

a 10% capacity factor. If so required, the new emissions limit would allow the facility to operate 

at a 45% capacity factor. 

This higher operational capacity factor, however, was determined to not be economically

favorable for the facility to operate at such a level continuously. Analysis showed that because 

residual fuel oil prices change with the cost of oil, the unit’s capacity factor over the last several 

years has been dropping because of the cost of fuel. Over the last decade, there has been a fairly

steady increase in residual fuel oil costs. This has reflected on the facility’s operating capacity, 

decreasing over the course of a single year. As the unit operates at a very low capacity factor on 

an annual basis, the SO2 emissions from that unit will be relatively low form a mass emissions 

perspective on an annual basis. Additionally, Regulation 1146 has required the facility to reduce 

their use of a maximum 1 percent sulfur fuel oil to a maximum half a percent sulfur fuel oil, 

reducing the emissions of the unit by roughly 50 percent. Given both of these factors, DNREC 

believes that both the fuel oil sulfur requirement and the economics residual fuel cost will 

generally keep the unit to operating at a low capacity factor. Therefore, DNREC believes that the 

actual SO2 emissions from this unit will not change significantly from the original emission limit 

in the regulation, nor will there be any significant impact on the air quality that would affect the 

public.

This SIP revision changes Regulation 1146’s Table 5-1 to read as follows:

Unit Annual SO2

Mass Emissions Limits (tons)

Edge Moor 3 1391

Edge Moor 4 2410

Edge Moor 5 4600

Indian River 1 1082

Indian River 2 1130
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Indian River 3 1759

Indian River 4 3657

McKee Run 3 439

Furthermore, no other aspects of the original regulation pertaining to SO2 will change with this 

SIP revision. The Edge Moor 5 facility will still be subject to the following:

Coal fired unit shall not exceed a SO2 emission rate of 0.37 lb/MMBTU heat input from May 1, 

2009 through December 31, 2011. Compliance with this requirement shall be demonstrated on a

rolling 24-hour average basis. Compliance can also be demonstrated with SO2 emissions from 

multiple units at a common facility be averaged on a heat input basis. 

No coal-fired unit subject to this regulation shall emit SO2 at a rate exceeding 0.26 lb/MMBTU

heat input, demonstrated on a rolling 24-hour average basis, on and after January 2012.

A coal-fired unit subject to this regulation shall not emit annual SO2 mass emissions that exceed 

the values shown in on or after January 1, 2009.

Compliance with these requirements from January 1, 2009 through December 31, 2011, may be 

achieved by demonstrating that the total number of tons of SO2 emitted from a common facility

does not exceed the sum of the tonnage limitations for all of the units subject to this regulation at 

that facility. Compliance shall also be achieved by using, tendering, or otherwise acquiring SO2

allowances under any State or Federal emission trading program. For the purpose of determining 

compliance with these requirements, the total tons for a specified period shall be calculated as the 

sum of all recorded hourly emissions, with any remaining fraction of a ton equal to or greater 

than 0.50 ton deemed to equal one ton and any remaining fraction of a ton less than 0.50 ton 

deemed to zero tons.

Overall, compliance with the requirements of this regulation shall be demonstrated with a 

continuous emissions monitoring system that is installed, calibrated, operated, and certified in 

accordance with 40 CFR Part 75 or other method approved by DNREC and EPA, and meeting 

the monitoring and reporting requirements of 40 CFR Part 96, subpart HHH.

No residual oil with a sulfur content in excess of 0.5 percent by weight, shall be received for any

residual oil-fired unit subject to this regulation, on and after January 1, 2009. Compliance with 

these requirements shall be demonstrated by fuel oil sampling and analysis. Samples shall be 

collected: (1) from the transport vessel for each shipment of residual fuel oil received at the 

facility for combustion in the subject residual oil-fired unit; or (2) from the supply pipeline each 

day residual oil is delivered to the facility via pipeline for combustion in a residual oil-fired unit 

subject to this regulation, after sufficient fuel oil has been drained from the sampling line to 

remove any fuel oil that may have been standing in the sampling line; or (3) from the supply

pipeline at the inlet to the residual oil-fired unit subject to this regulation each day the unit fires 

any quantity of oil fuel, after sufficient fuel oil has been drained from the sampling line to 
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remove any fuel that may have been standing in the sampling line.

D. EPA EVALUATION:

This amendment to Regulation No. 1146 is a reasonable compromise between Conectiv and 

DNREC, which prevented a potential overturning of the regulation. Analysis supports that the 

increase in the SO2 emissions limit for the Edge Moor 5 facility will generally not lead to 

increased SO2 emissions on an annual basis but will enable the facility to operate at a higher 

capacity if in the unusual circumstance it should be needed. Given that an increase in SO2

emissions is not expected from what they currently are at the facility, this revision will continue 

to help Delaware attain and maintain NAAQS for ozone and PM2.5. 

E. CONCLUSIONS AND RECOMMENDED AGENCY ACTION:

The amendment to the EGU multi-pollutant regulation on NOx and SO2 emission limitations 

adopted by Delaware will result in the reduction of NOx and SO2 emissions from the affected 

sources. The settlement between Conectiv and DNREC removed the risk of an adverse result 

that could have overturned this regulation entirely, a result that would not have been good for the 

environment or public health. Therefore, EPA approval of the SIP revision is recommended.