TULSA, Okla., March 6, 2006 – Public Service Company of Oklahoma (PSO), a unit of American Electric Power (NYSE: AEP), has approved a proposal to add 170 megawatts (MW) of generating capacity to the company’s Riverside Station (RVS), located in Jenks, Okla.

The plan is one of several submitted in response to a Request For Proposals (RFP) issued in September 2005, in which PSO announced it was seeking bids for up to 500 MW of new peaking capacity to be online in 2008. The expansion plan for RVS is one of three “self-build” proposals submitted by PSO. Additional peaking proposals are still being evaluated.

Currently, the plant can generate just over 900 MW using its two conventional gas-fired steam turbine generators. With the addition of two new gas combustion turbines, the plant’s peak capacity will increase to nearly 1,100 MW.

The project cost for the expansion at Riverside Station is estimated at $56.7 million.

In addition to the peaking proposals, PSO issued a RFP in December 2005, seeking up to 600 MW of new baseload generation to be online in 2011. Bids submitted by the Feb. 16, 2006 deadline are currently being evaluated. A decision on the selection of the winning bid is expected by mid-June.

PSO, a unit of American Electric Power, is an electric utility company serving approximately 511,000 customers in eastern and southwestern Oklahoma. Based in Tulsa, PSO has more than 4,000 megawatts of generating capacity.

American Electric Power is one of the largest electric utilities in the United States, delivering electricity to more than 5 million customers in 11 states. AEP is the nation’s largest generator of electricity, owning more than 36,000 megawatts of generating capacity in the U.S. AEP also owns the nation’s largest electricity transmission system, a nearly 39,000-mile network that includes more 765 kilovolt extra-high voltage transmission lines than all other U.S. transmission systems combined. AEP’s utility units operate as AEP Ohio, AEP Texas, Appalachian Power (in Virginia, West Virginia and Tennessee), Indiana Michigan Power, Kentucky Power, Public Service Company of Oklahoma, and Southwestern Electric Power Company (in Arkansas, Louisiana and east Texas). American Electric Power, based in Columbus, Ohio, is celebrating its 100th anniversary in 2006.

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News releases and other information about PSO can be found on the World Wide Web at PSOklahoma.com.