BUTTE, Mont. -

NorthWestern Energy says it wants to replace its aging general office building with a $23 million building, if it can reach a development agreement with Butte-Silver Bow County.

CEO Bob Rowe said Monday the company is working with the local government to trade city-owned property on the corner of Park and Main streets for the old NorthWestern Energy building. It also is working to obtain tax credits.

About 200 employees work at the old location, some parts of which date back to the early 1900s.

The new building would be five stories tall and 110,000 square feet. NorthWestern Energy officials say it would be constructed to blend in with its historic surroundings.

Rowe says if the agreements can be reached, construction could start early next year.