HELENA, Mont. (AP) — The Montana Public Service Commission has decided look for a consultant to help it evaluate whether NorthWestern Energy's proposed purchase of 11 hydroelectric dams from PPL Montana is a good deal for its customers.

NorthWestern announced last month it planned to buy the dams for $900 million to provide power for its Montana electric customers at steady prices.

The purchase price would be passed on to ratepayers and must be approved by several regulators, including the PSC.

Lee Newspapers of Montana reports commissioners agreed with a staff recommendation Tuesday to look into hiring a consultant who is more familiar with the software being used to compare the long-term costs of buying the dams against the costs if NorthWestern continued to buy power from other companies.

NorthWestern expects rates to increase by 5 percent with the dam purchases.