Buried within NorthWestern Energy’s request to increase Montanan electric rates by $35 million a year is a proposal that solar-power installers say could knee-cap their business — a new rate structure for “net metered” rooftop solar systems.

“What I’ve been hearing from our installer members is that they’re kind of looking down the barrel of a loaded gun,” says Andrew Valainis of the Montana Renewable Power Association. “They’re very nervous about the proposal. … We’re concerned that this could really devastate the industry.”