Building generation capacity for the grid we have now

The US energy transition gets most of the headlines. But the grid still has to work today.

Demand is rising. Peak periods are harder to manage. And utilities require generation that can respond quickly when the system needs support. Renewables are scaling, transmission is being upgraded, manufacturing is expanding- but none of that changes the fact that reliable, dispatchable power is what keeps the lights on right now.

That’s the backdrop to Bennett Mountain.

What the project involves

AtkinsRéalis has been selected by MasTec Industrial Corporation to serve as Engineer of Record for Idaho Power’s planned Bennett Mountain Power Plant expansion in Boise, Idaho.

The project adds 162 megawatts of generation capacity to the existing facility through nine natural gas-powered reciprocating internal combustion engine units. Fast-start, flexible units designed to respond during peak usage, balance the grid, improve load-following capability, and stabilize service for the region.

The engineering scope is full multidiscipline: all major balance-of-plant systems, auxiliary systems, water and wastewater networks, cooling systems, fuel gas infrastructure, and civil, structural, mechanical, electrical, and instrumentation and controls design.

It’s also being delivered through a constructability-driven framework- meaning every design decision has to hold up in the field, not just on the drawing. Pipe routes affect access, sequencing, and safety. A controls decision shapes how operators respond when demand spikes. Layout reviews are about constructability and performance, not just fit. When you’re expanding a live facility with this level of technical integration, there’s no room for disciplines working in isolation.

Why this kind of work matters

Not every project is about building something new from scratch. Bennett Mountain is about adding generation capacity to a grid that’s already under pressure to produce real, dispatchable power that helps keep the system stable while the wider transition continues.

For engineers, that means your decisions live in physical systems that communities depend on. The plant only performs when every discipline works together. The stakes are tangible and the feedback loop is short.

Part of a bigger US Power & Energy portfolio

Bennett Mountain sits alongside a growing body of work across US Power & Energy.

In Puerto Rico, AtkinsRéalis is supporting LUMA on a major grid hardening program to permanently strengthen transmission and distribution infrastructure. Up in the Northeast, a multi-year Master Service Agreement with Avangrid Networks covers utility capital program delivery across four utilities. While down south, AtkinsRéalis delivered the tech stack for Hanwha Qcells’ $2.5 billion solar manufacturing expansion in Georgia.

Manufacturing. Generation. Transmission. Distribution. Utility delivery. AtkinsRéalis brings more than 100 years of global energy experience to this work, with more than 50,000 megawatts of thermal energy delivered and 35 reciprocating engine projects completed worldwide.

Some projects ask you to imagine the future. Others ask you to make sure tomorrow morning works.

Explore our Power & Energy roles in the US and join the team that’s building what lasts.