Cheap surplus electrical power Brigham City has purchased from the Western Area Power Administration for the past eight years will be unavailable after Oct. 1, so the city is looking to Idaho for an alternative to buying supplemental power from Utah Power & Light Co.

Although city officials say they will have to do a lot of juggling to make up the difference, they don't expect it to raise costs for consumers.Brigham City is one of 33 cities statewide that belongs to the Utah Associated Municipal Power Systems, an association formed to pool energy resources at cheaper rates.

Beginning in October, WAPA, which supplies the city with its main power source, will give the city only its contracted amount for the year and nothing extra. New cities that have joined WAPA in recent years have forced the surplus cutoff, said Jim Davis, Brigham City director of public power.

With that in mind, UAMPS is offering the city a new share of cheaper power from Idaho.

Council members were given until Feb. 15 to decide whether they will participate.

But there's a catch.

John K. Haws, pooling administrator for UAMPS, said his organization three years ago contracted for power from Deseret Generation and Transmission, near Vernal, at what was then a competitive rate. Since then, energy prices have dropped, leaving them stuck with an allocation of more expensive energy that they must pay for, regardless of whether they use it.

Meanwhile, they are in the position to be able to purchase power from Idaho at less than half the Deseret price. However, the Deseret contract doesn't expire until December 1990 and contains a clause specifying that if UAMPS buys power elsewhere, it must still pay Deseret.

That means if Brigham City wants to purchase the cheaper Idaho power, it must first buy the more expensive Deseret power through 1990, Davis said.