Midwest Independent Mailing Address: Overnight Deliveries: www.midwestiso.org 

Transmission System Operator, Inc. P. O. Box 4202 701 City Center Drive 317-249-5400 

 Carmel, IN 46082-4202 Carmel, IN 46032 

Arthur W. Iler 

Assistant General Counsel 

Direct Dial: 317-249-5497 

E-mail: ailer@midwestiso.org 

September 8, 2010 

EPA Docket Center (6102T) 

1200 Pennsylvania Ave., NW. 

Washington, DC 20460 

Re: Docket ID No. EPA-HQ-OAR-2010-0295

Dear Sir/Madam, 

The Midwest Independent Transmission System Operator, Inc. (“Midwest ISO”) is a 

fully integrated regional transmission organization (“RTO”) whose operational area consists of 

parts of 13 states and the province of Manitoba. The non-profit Midwest ISO administers a 

common wholesale tariff to assure industry consumers of unbiased regional grid management 

and open access to the transmission facilities under Midwest ISO's functional supervision. The 

Midwest ISO appreciates the opportunity to comment on the amendments to its regulations 

governing the operation of stationary internal combustion engines that the Environmental 

Protection Agency (“EPA”) proposed on June 8, 2010, in part, because the proposed 

amendments are in apparent conflict with section 69.3.5 of the Midwest ISO’s Federal Energy 

Regulatory Commission (“FERC”) approved Open Access Transmission and Energy and 

Operating Reserves Markets Tariff (“Tariff”). 

Currently, the Midwest ISO has almost 10,000 MW of Load Modifying Resources. Of 

that 10,000 MW, over 5,000 MW of such Resources are from behind-the-meter generation, 

including many internal combustion engines. The proposed amendments to Section 60.4243 d 

(4) of the EPA’s regulations would, among other conditions, impose a maximum 15-hour per 

year limit on the operation of a stationary internal combustion engines as part of a demand 

response program of an RTO (such as the Midwest ISO) during emergency conditions. 

Furthermore, the proposed amendment would provide that the 15 hours per year of demand 

response operation would be counted as part of the 50 hours of operation per year provided for 

“non-emergency situations”. 

The Midwest ISO’s Tariff, which has been approved by the FERC, provides that entities 

may qualify resources (which often include internal combustion engines) as Demand Resources 

to provide generating capacity to the Midwest ISO Region during emergency conditions. 

Subsections 69.3.5(iv) and (v) of the Tariff, provide, in part, that in order for a resource to 

qualify as a capacity resource, the resource must be capable of being operated (during 

Emergency conditions where the reliability of the electric grid needs to be maintained) a 

minimum of at least five times for at least four continuous hours per event during the Summer 

Season during any Planning Year (June 1st through May 31st of the following calendar year). 
Docket ID No. EPA-HQ-OAR-2010-0295 

September 8, 2010 

Page 2 

Thus, internal combustion engines that seek to be qualified as Demand Resources within the 

Midwest ISO Region must be capable of being operated for a total of at least 20 hours per 

Planning Year. Other RTOs have similar operational requirements for emergency capacity 

resources. 

In order to allow customers to meet the minimum requirements for qualifying these 

resources as capacity resources under the Tariff, the Midwest ISO is requesting that the 

emergency usage time being proposed in the amendments to Section 60.4243 (d) (4) be modified 

consistent with the Demand Response qualification requirements developed by RTOs and 

approved by the FERC. Such modification to the subject proposed amendment would: (1) 

increase the total number of hours that an emergency internal combustion engine could operate 

during a year from 15 to at least 20 hours; and (2) clarify that such operations would be counted 

as emergency, rather than non-emergency operations. Although the Midwest ISO understands 

the potential environmental concerns associated with these resources, the Midwest ISO 

respectfully requests that the EPA also recognize the importance of balancing environmental 

concerns with the need to maintain electric grid system reliability during emergency conditions 

by using appropriate and consistent reliability standards for emergency stationary internal 

combustion engines. 

Thank you for the opportunity to provide these comments. Please feel free to contact me 

if you have any further questions regarding the comments outlined in this letter. 

Sincerely, 

/s/ Arthur W. Iler 

Arthur W. Iler 

Assistant General Counsel