BOISE, Idaho — Idaho Power wants to retire two coal-fired power plants it says won’t be able to produce electricity at competitive prices as part of a 20-year plan to provide energy for Idaho and Oregon that has drawn concerns about cost, pollution and energy needs.

Boise-based memory chipmaker Micron Technology, one of the state’s largest employers, is among those companies that intervened ahead of a late August deadline. The Sierra Club also voiced concerns, saying the coal plants aren’t shutting down fast enough.

Idaho Power, in the 155-page Integrated Resource Plan released in June, considers a 300-megawatt natural gas facility by 2033 in southwestern Idaho and completing a 300-mile (480-kilometer) transmission line to Oregon to tap into the Pacific Northwest energy market.

The company says in its analysis of multiple possible scenarios said shutting down ahead of schedule two units at the Jim Bridger coal plant in Wyoming in 2028 and 2032 produced the best results for customers.

“This is really an economic decision,” said Idaho Power spokesman Brad Bowlin, noting the coal plant needs expensive environmental upgrades that make switching to other options desirable to produce those 700 megawatts.

The first of those options, Bowlin said, is completing the powerline from the company’s Hemingway Substation southwest of Boise, Idaho, to Boardman, Oregon, an energy hub. The 500-kilovolt line would increase energy exchanging capacity between the Pacific Northwest and Intermountain West.

The Boardman-to-Hemingway Transmission Line Project would allow Idaho Power to tap into a glut of Pacific Northwest energy caused in part by increased renewable energy including solar power capacity in California, Bowlin said.

The company has determined buying that energy will be cheaper than producing energy at the coal plant. The line would be built by 2024 at the earliest.

However, one of the interveners is called Stop B2H, which describes itself as an alliance of citizen organizations and individuals located within sight of the proposed power line. The group in its petition to intervene questioned the need for the powerline and said it intends to show that “other, more cost-effective resources exist.”

Micron in its petition said Idaho Power’s plan could affect how much Micron pays for energy and even Idaho Power’s “ability to reliably serve Micron.”

Marc Musgrove, a Micron spokesman, said in an email Friday that the company was working on a possible response to an inquiry from The Associated Press but didn’t immediately have one.

Sierra Club, an environmental group, in its petition focused on the company’s plan to move away from coal energy and specifically on the Jim Bridger coal plant.

“Sierra Club’s members have an interest in ensuring that the company’s future ‘resource menu’ not only meets load but ensures cleaner, more cost-effective resources,” the group said.

Other interveners included ground-water pumpers and industrial power users concerned about the cost of electricity.

Idaho Power has 534,000 customers in southern Idaho and eastern Oregon, and expects to add 222,000 over the next two decades. Currently, the company generates 39 percent of its electricity from 17 hydropower facilities.

The company buys 27 percent of its electricity from the energy market and independent power producers, gets 24 percent from three coal plants and 10 percent from three natural gas plants and a diesel facility.

The company operates as a state-regulated monopoly and in return is required to provide reliable and adequate electric service at the lowest cost and least risk to customers. As part of that process, the company files the Integrated Resource Plan with the Idaho Public Utilities Commission every two years, providing the public a snapshot of the company’s activities.

The commission is currently taking public comments on the company’s plan, and hasn’t yet set an end date for those comments.