John Quinn 1 00 Constellation Way

Director

– Environmental Affairs Suite 1000C Baltimore, Maryland 21202 410-470- 1751 443-213-3204 Fax

3 Septem ber, 20 10 Via email and post Robert Wayland, Group Leader Energy Strategies Group US EPA Research Triangle Park, North Carolina 27711 Mail Drop D243-01 Cc: Melanie King

Re: Petition for Reconsideration of National Emission Standards for Hazardous Ai r Pollutants for Reciprocating Internal Combustion Engines, Final Rule RIN 2060 -AP36 EPA Docket No. OAR-2008-0708 Dear Ms. Jackson: Constellation Energy appreciates the opportunity to express support for EnerNOC’s Petition for Reconsideration of National Em ission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines, Final Rule , submitted by Beveridge & Diamond, PC, May 27, 2010. We understand EPA has granted the petition for reconsideration. Constellation Energy Constellation Energy (www.constellation.com ) is a leading supplier of energy p roducts and services to wholesale and retail electric and natural gas customers. It owns a diversified fleet of generating units located in the United States and Canada, totaling approximately 9,000 megawatts of generating capacity, and is am ong the leaders pursuing the development of new nuclear plants in the United States. The com pa ny

d elivers electricity and natural gas through the Baltimore Gas and Electric Company ( BGE), its regulated utility in Central Maryl and. A FORTUNE 500 company h eadquartered in Baltimore, Constellation Energy had revenues of $15.6 billion in 2009. Petiti on for Reconsideration – Change 15-hour limit on emergency engines to 60 hours or the minimum hours required by the ISO , whichever is less Constellation Energy supports EnerNOC’s petition for reconsideration of the rule, specifically with respect to the 1 5- hour operating limit on emergency DR. The 15 hour limit for emergency engine operation in the regulation currently says, “The 50 hours per year for non-em ergency situations cannot be used for peakshaving or to generate income for a facility to supply power to an electric grid or otherwise supply power

as part of a financial arrangement with another entity; except that owners and operators may operate the emergency engine for a maximum of 15 hours per year as part of a DR program if the regional transmission organization or equivalent balancing authority and transmission operator has determined there are em ergency conditions that could lead to a potential electrical blackout, such as unusually low frequency, equipment overload, capacity or energy deficie ncy, or unacceptable voltage level.” Constellation Energy favors EnerNOC’s request that the italicized language above be revised to read,
" ... may operate the emergency engine for a maximum of 60 hours per year or the minimum hours required by Independent System Operator tariff, whichever is less .. ." The Rationale behind the request for 60 hours is: 1. ISOs do not have the discretion to dispatch DR resources to take advantage of the greater hours. The em ergency D R p rograms are only called under very s pecific, planned, and controlled circumstances. The system operator mu st report operation in any e me rgency state to NERC. NERC requires development of formal plans for Capacity and Energy Em ergencies, and precise im plem entation when calling emergency DR events. 2. The 15 hour limit may p revent emergency

e ngines from participating in em ergency DR programs. The PJM FERC Tariff for the Em ergency Load Response program requires a mi nimum availability of 60 hours. PJM’s Reliability Assurance Agreement states that a party mu st agree to reserve for interruption ...at least 10 interruptions per planning period. In addition, a party mu st agree to reserve interruptions of at least 6- hour duration. Hence the 60 hours: 10 interruptions at 6 hours duration per year. In sum mary, Constellation Energy feels a 60- hour or ISO lim it is more rational; based on the existing ISO system reliability requirements for this equipment. Respectfully,

John Quinn Director, Environmental Affairs Constellation Energy Cc: Melanie King King.Melanie@epamail.epa.gov