I honestly don't know.  The Denver Post paints a much more complex picture:

Mechanical malfunctions, inaccurate weather forecasts and inadequate natural-gas supplies caused the rolling power outages that afflicted 325,000 customers of Xcel Energy on Saturday.

It marked the first time in Xcel's institutional memory that controlled electrical outages occurred in the winter.

Such disruptions typically happen on the hottest summer days when demand for power peaks.

Three outages of 30 minutes each hit customers in portions of metro Denver, Grand Junction and the central mountains. The outages lasted longer than 30 minutes for about 25,000 customers.

"The phrase 'perfect storm' is overworked, but we've never seen events like this," said Xcel spokesman Mark Stutz.

Portions of three coal-fired power plants in Colorado were out of commission Saturday morning, either for scheduled maintenance or because of mechanical breakdowns.

In addition, Xcel had inadequate supplies of natural gas on hand because initial weather forecasts had not suggested the record-breaking low of minus 13 on Saturday.

The utility had enough natural gas for all of its customers' heating needs, but it ran short of the fuel to supply gas-fired power generators that supplement the electricity produced by coal-fired power plants.

The gas shortage was exacerbated by an undetermined number of Rocky Mountain natural-gas wells whose pumping equipment froze, preventing additional deliveries.