There are a number of factors that drive utility costs up that are not associated with retiring old coal plants due to environmental issues or the rise of renewable energy.  A discussion about where we need to go with grid design and use of renewables is important to reduce future costs due to resistance to change.
Coal for the Pueblo plant comes from Wyoming where not only is there the initial fuel cost but also the transportation cost. The plant in Pueblo supplies a large region including Denver but there are the electrical transmission costs associated with moving that energy back to Denver. Pueblo gets most of its energy from Black Hills that just built a number of new gas generators not far from the Xcel plant which cost a billion dollars to build.  Xcel customers see rate increase to pay back that billion dollars plus interest and Black Hills customers see a rate increase to pay back the half billion dollar capital investment plus interest.