Rates will increase 4.2 percent in January for customers of Minnesota's third-largest natural gas utility, which serves many Twin Cities suburbs, Duluth, Rochester and other cities.

The state Public Utilities Commission on Thursday approved the interim increase for most of the 214,000 customers of Minnesota Energy Resources Corp., based in Rosemount, as the company's request for a $14 million, or 5.5 percent, permanent increase in revenue is reviewed.

The higher interim rates will cost a typical customer $3.35 per month, or $40.21 a year. If regulators later set a lower permanent rate increase, customers would get refunds with interest.

It is the company's third rate hike request since 2008, when rates went up 5.5 percent. In 2010, rates rose 4.1 percent. The increases only apply to the cost of delivering gas. Utilities don't make money on gas itself and fuel price changes are passed on to customers.

Customers' overall payments are lower today than six years ago, when natural gas prices peaked, according to the company.

Minnesota Energy Resources, a subsidiary of Chicago-based Integrys Energy Group, serves 165 communities, including Cottage Grove, Eagan, Farmington, Lakeville, Prior Lake and Rosemount.

David Shaffer • 612-673-7090