Two groups sometimes at odds with each other - big industrial power users and environmentalists - have joined forces in objecting to Idaho Power Co.'s request for a natural-gas plant in western Idaho.

The recession and other factors mean Idaho Power doesn't deserve an expedited decision, said the Northwest and Intermountain Power Producers Coalition, an advocate for nonutility, independent power producers like Wolverine Creek Energy Center, a wind farm in eastern Idaho.

The $427 million plant would be built off Interstate 84 south of New Plymouth. Idaho Power says it needs the plant soon to meet the rising demand for electricity as Idaho grows. The economy may be slowing, but consumption of power is not, spokeswoman Echo Campbell said.

Peter Richardson, a lawyer for industrial customers, said if Idaho Power gets everything it wants, it would mean an average 8 percent rate increase.

Ken Miller, energy program director of the Snake River Alliance, an environmental group, said the alliance supports Idaho Power's efforts to use more renewable energy resources and questions the wisdom of a natural gas plant.

"There's a lot of price volatility associated with gas," Miller said. "If gas prices are higher, that cost is going to be passed on to customers."

Idaho Power hopes for a decision by the state sometime this fall, said Gene Fadness, a spokesman for the Idaho Public Utilities Commission. "That's really quick for this sort of project," Fadness said.

Idaho Power must consider future as well as current power needs, Campbell said. Data indicates power production won't keep up with demand without a new plant, said Campbell.

But Miller says Idaho Power is using numbers developed before the recession. "We are asking the commission to delay the decision until new numbers can be gathered," he said. Richardson agrees, saying we need "a better understanding of market conditions and power demand."

Idaho Power supplements its own power with often costly purchases from other companies. If the plant is not built, more power will have to be purchased, and that will translate into much higher rates, hurting economic development, Campbell said.

"Idaho has very low power rates compared to the rest of the country, and that makes Idaho very attractive for businesses," she said.

Aimee Niles: 377-6439