SEMCO ENERGY, Inc., a privately held company, distributes natural gas to approximately 409,000 customers combined in Michigan and in Alaska.

SEMCO ENERGY GAS COMPANY (a division of SEMCO ENERGY, Inc.) distributes natural gas to 282,500 customers in 24 counties in Michigan's upper and lower peninsulas.

ENSTAR Natural Gas Company distributes natural gas to approximately 126,000 customers in the Anchorage, Alaska area.

SEMCO ENERGY VENTURES acquires and operates businesses involved in propane distribution, interstate pipelines and natural gas storage business in various regions of the United States.