The company said it has issued a request for information to owners or developers of potential projects. Responses are due by the end of September.
John Hines, NorthWestern's chief energy supply officer, says the RFI is open to all qualified renewable energy resources, including wind, biomass, landfill gas and hydrogen.
The company would prefer to purchase the projects, but it will consider other options such as an equity interest in a larger project or long-term power purchase agreements. It will only consider projects that deliver both renewable energy and the associated renewable energy credits.