HARRISBURG — The Pennsylvania Public Utility Commission is alerting consumers about the potential for large winter energy cost increases for electric customers who do not shop for competitive electric suppliers.

To avoid the possibility of “sticker shock” from high bills during the coming cold months, the PUC reminds consumers that the start of winter is an important time to compare prices for electric generation and evaluate competitive supplier options.

Most Pennsylvania regulated electric utilities adjusted the price they charge for the generation portion of customers’ bills on Dec. 1 for default service customers, also known as the price to compare.

The generation rate averages 40 to 60 percent of the customer’s total utility bill. However, the percent varies by utility and by the level of individual customer usage. These recent changes in price range from a reduction of 6.3 percent to an increase of 24 percent.

For example, as of Dec. 1, Penelec’s PTC increased from 5.198 cents to 6.445 cents per kilowatt hour.

In most areas of Pennsylvania, consumers can choose who supplies their electricity, based on price or other factors, such as renewable energy.

Customers not choosing a supplier continue to receive default service from their local utility, with the cost per kilowatt hour set quarterly or semiannually based on electric generation procurement plans developed by those utilities.

According to the PUC’s most recent electric switching report, more than 1.8 million — 31 percent — of residential and business customers currently have their electric generation provided by competitive suppliers. In the residential rate class, more than 1.5 million customers — about 24 percent — are enrolled with competitive suppliers.