In July, Idaho Power Co. hit its peak in power demand two days in a row as temperatures in Boise reached 110 degrees.
At 3,407 megawatts, the utility that serves 500,000 customers in Idaho and eastern Oregon was turning on every generator it could find. Those included the 318-megawatt natural gas-fired Langley Gulch Power Plant, 925 megawatts from it 17 hydroelectric plants, 947 megawatts from its share of coal plants in Wyoming, Nevada and Oregon.
It also turned on two extremely expensive-per-megawatt natural gas “peaker” plants near Mountain Home. The utility was tapping into its reserves to meet its demand.
“It was certainly stressing the limits of our capabilities,” Mark Stokes, Idaho Power’s water and resource planning director told the Northwest Power and Conservation Council Tuesday at the Hampton Inn in Boise.
The 675 megawatts of wind power the utility must buy under contracts only provided 48 megawatts of power, he said, helping only when the wind picked up in the afternoons of the hot spell.
But Idaho Power’s system would not have been stressed had it had the 327 megawatts of demand response programs available it had the year before. The public utility had convinced the Idaho Public Utility Commission it did not need its A/C Cool Credit program, or the Irrigation Peak Rewards program, which turned off irrigation pumps.
“Had we had those available everything would have been fine,” Stokes said.
It used only 35 megawatts of demand response available from industrial customers.
Last month after a year of talks with customer and conservation groups Idaho Power announced a new demand response program that brings back the two programs shut down this year. The settlement is designed to delay construction of new peaker plants, avoid transmission line losses and provide improved reliability during emergencies.
Previously, the utility’s demand response program had been simply viewed a way to expand its electric power capacity during peak seasons.
For Stokes the take away message was that Idaho Power was forced to purchase more wind than makes sense for its customers needs and that even without renewable energy standards Idaho Power has about 19 percent new renewable on its system. That better than some surrounding states with the legislatively-mandated standards.
“Wind is not a really good fit for our system,” Stokes said.
“It has nothing to do with Idaho Power being against renewables,” Stokes said.