Illinois Power Company (IP), now operating as AmerenIP, has formally been integrated into the Midwest Independent Transmission System Operator, Inc. (Midwest ISO) system, the two companies announced Friday.

The company's inclusion into the Midwest ISO system, which took effect just before midnight Thursday, Sept. 30, further expands interconnections for transmission service between Midwest ISO members.

"This is an important step forward that will further link our east and west operations," said James P. Torgerson, president and chief executive officer for the Midwest ISO. "The inclusion of AmerenIP creates a more continuous transmission system throughout the Midwest region that benefits our members and their customers."

AmerenIP, based in Decatur, Illinois, serves approximately 600,000 electric and 415,000 natural gas customers in a 15,000 square-mile territory across Illinois. The company operates a control area of more than 4000 MW.

On March 25, Ameren asked the Federal Energy Regulatory Commission (FERC) to approve its acquisition of IP and to transfer functional control of IP's transmission system to the Midwest ISO. The FERC approved Ameren's application on July 28. Ameren's other operating companies -- AmerenUE, AmerenCIPS and AmerenCILCO -- were already transmission owning members of the Midwest ISO.

"Ameren now has all of its operating companies' transmission systems in the Midwest ISO," said David Whiteley, Senior Vice President, Energy Delivery for Ameren. "AmerenIP customers should see no change in the reliable service they have always received. And with control of our transmission assets consolidated under the Midwest ISO, Ameren will be able to more efficiently manage our portion of the grid. We look forward to the implementation of the Midwest ISO market-based congestion management system."

Torgerson said AmerenIP's membership in the Midwest ISO will simplify and improve the sale of transmission service between Mid-Continent Power Pool (MAPP) and East Central Reliability Council (ECAR).

"As a result of AmerenIP's integration, the Midwest ISO has greater control over the facilities we oversee, allowing us to extend the benefits of a regional grid to more customers throughout the Midwest," Torgerson said. "We're pleased to have them as a member."

Midwest ISO customers benefit from increased access to multiple generation sources within the Eastern Interconnection, as well as the elimination of multiple transmission charges, Torgerson added.

In its role as a FERC-approved Regional Transmission Organization, Midwest ISO is responsible for the following:

* Administering a single region-wide tariff
* Maintaining the Midwest ISO's Open Access Same-time Information System (OASIS) Web site
* Providing region-wide market monitoring services
* Managing parallel path flows for the region
* Maintaining operational authority
* Monitoring all critical facilities in the Midwest ISO region
* Monitoring reliability and network security for the region
* Developing and implementing market-based congestion management measures.