Black Hills Energy is asking the state Public Utilities Commission for a package of rate hikes to help pay for a gas-fired generator in Pueblo to replace its coal-fired plant in Cañon City, which closed in December 2012 under pressure for clean-air advocates. Black Hills is asking to create tiered rates for customers who use higher amounts of energy, similar to the summertime rates charged by Xcel Energy. The utility also wants to raise its minimum monthly residential rate from $16.89 to $20.13.