The New Progressive Tax: Your Power Bill

I read today on the Raleigh News & Observer that the conservationists in the NC General Assembly are thinking about the idea of tiered electric rates. Here's the article. In a nutshell, if one is able to do so, state lawmakers are considering changing how people are charged for electric usage. Higher tier users would be charged a higher rate per unit compared to those that use little a lower amount per unit. Currently the state's power companies charge a flat rate per unit, save for Duke Power, but this new proposal would allow the state's public utilities commission to overhaul the rate plans.

This new proposal was introduced by Patsy Keever, a Democrat from Buncumb County. Why is this a bad idea?