A consulting company hired to evaluate NorthWestern Energy's planned $900 million purchase of 11 hydro-electric dams has raised several questions, including whether NorthWestern's plan budgets enough money for operations and maintenance of the dams.

Bob Decker, public policy chief for the Montana Public Service Commission, tells the Great Falls Tribune ( ) that the PSC hired The Essex Partnership to raise any concerns or questions that should be considered as part of the proposed sale.

The analysis by The Essex Partnership relied on information provided by NorthWestern Energy, not on-site analysis.

William Rhoads, NorthWestern Energy general manager for power generation, says the Essex analysis was not as complete as the study NorthWestern did and raised unfounded concerns.