ComEd Releases Preferred Sites for IPP Interconnection in Northern Illinois

Wednesday, May 8, 2002 After successfully connecting 19 new independent merchant generating projects totaling over 8,500 MW since first announcing preferred sites for interconnection of new generation in June 1998, today ComEd announced 12 sites (See Map) in Northern Illinois best suited for the interconnection of new generating facilities within the existing transmission system.

In addition, ComEd has enhanced its posting by identifying unfavorable sites in terms of the potential for transmission constraints.

The list reflects current transmission system conditions. The list does not suggest that these sites are best from an environmental aspect, fuel or water availability, or local zoning perspectives. ComEd encourages developers to work with community officials to determine the best fit for generation expansion while considering local land development issues.

From 1999 through 2001, ComEd interconnected nine new independent power producer (IPP) generating plants, totaling 5076 MW, to its transmission system. Another seven plants, with a capacity of over 3400 MW are expected to come on line in 2002. The original list of preferred sites was first published in June of 1998.

In developing the list of proposed sites, ComEd analyzed its electrical network and identified locations where new facilities could connect to the transmission system so as to maximize power delivery from the generating facility while minimizing transmission network upgrades.

While the extent of the impact of any particular new generating facility, or the specific transmission system upgrades, cannot be determined without a specific study of the proposed interconnecting generation facility, generation at these favorable sites appears to be least likely to cause severe system impact or cause expensive transmission system modifications. ComEd hopes that the identification of favorable sites will further contribute to development of power generation in Northern Illinois in a manner that will maximize consumer benefits.

"We attempted to identify those areas within our service territory that could accommodate substantial new generation with minimal required system upgrades," said ComEd Vice President for Transmission Operations and Planning, Bruce Renwick. "ComEd is doing its part to support the competitive electricity market in Illinois. The presence of IPPs connected to the ComEd transmission system provides for a more diverse marketplace and a more reliable power delivery system for our customers."

The proposed sites are:

ComEd has also identified unfavorable interconnection locations. Unfavorable sites are generally defined as locations that could likely require transmission upgrades in excess of $20M to interconnect and deliver the output of the proposed plant. According to Renwick, ComEd wanted to inform developers about areas of potential transmission constraints. Renwick noted that it's possible that the existing generation configuration could change in a way that would alter the designation of unfavorable sites, and suggested that generation developers or designated merchant agents submit a Transmission Service Request via the Open Access Same-time Information System to formally ascertain the availability of transmission capacity to deliver the output of a proposed plant.

ComEd typically specifies a 345 kV interconnection for proposed generating plants exceeding 300 MW. Although the map only depicts 345 kV interconnection sites, there may be suitable 138 kV interconnection locations for smaller plants within the areas designated as unfavorable locations. Generation developers are encouraged to submit requests to interconnect at any time and at any location.

Commonwealth Edison is a unit of Chicago-based Exelon Corporation (NYSE: EXC), one the nation's largest electric utilities with more than $15 billion in revenues and a customer base of five million. ComEd provides service to more than 3.4 million customers across Northern Illinois, or 70 percent of the state's population.