Xcel Energy 

Xcel Energy manages utilities serving 3.9 million electric customers and 2.2 million natural gas customers in eight states. Its utilities are Northern States Power, which serves customers in Minnesota, North Dakota, South Dakota, Wisconsin, and Michigan; Public Service Company of Colorado; and Southwestern Public Service Company, which serves customers in Texas and New Mexico. It is one of the largest renewable energy suppliers in the US, with more than half of its electricity sales coming from carbon-free energy.