ComEd customers can expect electricity rates nearly 50% above what they were last summer, a consumer advocacy group said.

The Citizens Utility Board cautioned that, despite the rate spike, consumers should not look toward alternative energy suppliers for cost savings.

Electricity customers can expect to pay 10% to 15% more monthly, or about $10.60 more a month, this winter, CUB said.

The impact can be higher on individual customers depending on the impact of factors, including the weather, CUB said.

Even with the higher rates, CUB cautioned against “bad alternative supplier deals.”

Alternative suppliers typically make door-to-door and phone sales efforts during times of rising rates.

Even with the elevated rates, CUB warned customers of ”bad alternative supplier deals" and stressed that “it is likely ComEd is the best bet,” CUB said in a news release.

According to CUB, Illinois consumers have lost more than $2 billion in the past decade by switching to alternative suppliers.

“ComEd’s price is painfully high, but customers should beware of bad deals peddled by alternative suppliers,” CUB Executive Director Sarah Moskowitz said in a news release. “Even in this market it is likely that ComEd is your best bet for supply.”

The ComEd price for electricity supply starting in October is 9.7 cents per kilowatt-hour, CUB said. That is down from the price of 10.03 cents per kilowatt hour during the summer, CUB said.

But the October price is still 47% above what it was last year, CUB said.

Increased energy demand from data centers has contributed to the price increase, CUB said.

Data centers, which process data for computer use, have increased the demand for electricity and have led to higher costs for average consumers.

.