Colorado's largest utility is raising its rates this summer-- but there's a twist.  Xcel will charge more for residential electricity... but only from June through September... and only if you use more than a certain amount of energy in those months. The approach is called "tiered pricing." And many other utilities already do it -- including Denver and Boulder water. Ryan Warner speaks with the Public Utilities Commission chairman Ron Binz.

First aired March 12, 2010