Many utilities already charge different prices for peak-use hours and non-peak hours.

California, the most extreme case, let generators charge market prices for power, but froze the rates that the utilities could charge consumers.

If the Millstone plants are allowed to operate longer, he said, the utility would charge less money a year for decommissioning.

Under traditional rate making, if regulators say that a new power plant is surplus the utility generally cannot charge its customers for the plant's cost.

Under utility regulation, utilities can charge their customers for increased interest costs.

Because they are legal monopolies, utilities must charge rates set by state regulators.

As a result, the utilities say, they have been paying as much $1 for each kilowatt of power, but can charge only about 6.5 cents.

That is, government agencies permit most utilities to charge enough for electricity and the like to cover their costs along with a reasonable profit.

Municipal utilities are tax-exempt, and therefore can charge less.

At such peak times, utilities charge businesses a premium for electricity, helping to make solar that much more attractive.