Aug 9 - McClatchy-Tribune Business News Formerly Knight Ridder/Tribune Business News - Russell Ray Tulsa World, Okla.

One day after AEP-PSO made an emergency appeal to customers to conserve electricity, the utility has stopped commenting on the downed generating unit that nearly caused rolling blackouts Monday in Tulsa.

The utility refused to comment on the progress it has made in repairing a 450-megawatt generating unit at a power plant in Jenks.

The unit was shut down over the weekend due to a leak in a boiler tube, which carries the water used to generate electricity. As a result, Tulsa businesses and residents faced the possibility of rolling blackouts because of 100-degree heat and strong demand.

With temperatures expected to reach or exceed 100 degrees later this week, American Electric Power-Public Service Company of Oklahoma won't say when the damaged unit will be returned to operation.

"Typically, we don't discuss the day-to-day operating status of any particular unit because of what impact it can have on the market," said AEP-PSO spokesman Stan Whiteford. "We don't want to see market prices going up based on things we say."

The generating unit at AEP-PSO's Riverside Station in Jenks is one of two that broke down Sunday. The other, at the Tulsa Power Station near 36th Street and Elwood Avenue, was repaired and placed back online late Monday, the utility said.

"We communicated more about our power generating facilities than we normally would (on Monday)," Whiteford said.

AEP-PSO President Stuart Solomon said the company's bottom line could be affected if it discloses the operating status of the Riverside unit.

"We don't discuss specifics on the operating status of these units because it may impact our ability to contract for the lowest-cost power in the market," Solomon said.

The threat of rolling blackouts -- deliberately engineered power outages that last one to two hours -- has passed, for now, AEP-PSO officials said.

"We fully expect to meet our demand requirements," Solomon said.

However, the utility did not rule out the possibility of another emergency appeal to cut consumption.

"If you lose another unit for any reason, then we could be back in that same situation," Whiteford said.

Last month, demand within AEP-PSO's service area surged to a high of 4,148 megawatts. Power usage was expected to near that mark Monday when the utility issued its appeal to cut consumption.

But demand fell far short of last month's peak as commercial and industrial customers responded to AEP-PSO's appeal by sharply reducing consumption.

"The emergency has passed for the time being," Whiteford said.

While AEP-PSO made it through Monday's challenge, the area continues to face triple-digit temperatures. The high Tuesday reached 100 degrees, and the heat is expected to persist through this weekend, said Peter Snyder, a meteorologist at the National Weather Service.

There is a slight chance of isolated thunderstorms in the next few days, with temperatures expected to be between the upper 90s and low 100s, he said.

AEP-PSO has more than 4,000 megawatts of capacity. It operates seven Oklahoma power plants, although some plants are about 40 years old. The Tulsa Power Station was built in the 1960s, and the Riverside Station was put into production in the 1970s, Whiteford said.

To meet demand, Whiteford said the company purchases power from outside suppliers. That's what the utility did Monday to overcome the crisis.

"We purchased whatever power that we could that was available," Whiteford said.

AEP-PSO is the state's second-largest electric utility, serving about 514,000 Oklahoma customers, including 285,000 in the Tulsa area.