The Bennett Mountain Gas Plant Expansion adds fast, flexible energy to keep power reliable and affordable as demand grows.
About the Project
Idaho Power is expanding the Bennett Mountain Power Plant near Mountain Home to help meet growing energy needs across our service area.
The expansion adds nine new generating units that can quickly produce electricity when demand is highest, like during hot summer days or very cold winter weather. To keep energy reliable and affordable, Idaho Power needs resources that can respond quickly when demand increases. While renewable energy sources like wind and solar are an important part of the energy mix, they depend on weather conditions. This project would add a flexible, fast-starting energy resource that can generate power when it’s needed most.
Because this expansion is located at an existing power plant, it can make use of infrastructure already in place, including a natural gas pipeline, substation, and transmission lines. This helps reduce overall costs. In total, these units could generate enough energy to serve up to 60,000 homes.
Purpose and Need
The Bennett Mountain Power Plant has safely operated in the Mountain Home area for more than 20 years, providing reliable energy to customers.
As energy needs have grown, Idaho Power evaluated options to add new capacity. Expanding this existing facility stood out as a practical solution because it can use current infrastructure and land, reducing both cost and environmental impact compared to developing a new site.
On March 10, 2026, the Idaho Public Utilities Commission approved a Certificate of Public Convenience and Necessity (CPCN) for the project, confirming its value for customers and its role in meeting future energy needs.
Benefits
Timeline and Current Status
Frequently Asked Questions
Why this location?
Expanding the existing Bennett Mountain facility allows Idaho Power to use infrastructure already in place, which helps reduce costs and limits the need for new land or major new construction.
What will the expansion include?
The project would add nine generating units. Each unit would include an exhaust stack up to about 90 feet tall.
How safe is the expanded gas plant?
Safety is a top priority for Idaho Power. The Bennett Mountain Power Plant has operated safely for more than 20 years, and the expanded facility will continue to follow strict safety standards and procedures.
The plant is operated by trained professionals and maintained using established safety practices for natural gas facilities. Idaho Power is also working closely with the Mountain Home Fire Department and Elmore County emergency responders to ensure a strong response plan is in place.
Overall, the expansion is designed, built, and operated to meet all applicable safety requirements and protect both employees and the surrounding community.
Will this affect air quality?
The expansion must meet all local and national air quality standards. Idaho Power has applied for a permit with the Idaho Department of Environmental Quality, which must be approved before construction can move forward.
Will there be more noise?
Some additional sound is expected, but the project will include noise-reduction measures, such as acoustic barriers and silencers, to keep sound levels similar to what’s experienced in the industrial area today.
How much water will the plant use?
Water use will be limited— roughly similar to what a couple of average homes use during normal operations. No new wells will be drilled, and Idaho Power is focused on using water responsibly and efficiently.
Questions?
Contact Steve Smythe at ssmythe@idahopower.com.