Ratepayers will see a 24 percent jump in the power supply charge portion of their electric bills for October after a summer of generally reduced use and lower bills.
A home that uses 775 kilowatt hours a month will see an increase of $11.
The power supply charge, which makes up about half of electric bills, will increase to 7.36 cents a kilowatt hour for October, after it had dropped to a record low of 5.95 cents in September.
Jeff Weir, a PSEG spokesman, said: "Given that the summer was far cooler than normal, the cost to serve the customer was less than projected, leading to significant decreases in the Power Supply Charge in August and September. As the weather and usage begins to normalize, the estimate for the Power Supply Charge normalizes."
The power supply charge is adjusted monthly to cover the utility's fluctuating cost for fuel and power purchased from plants and other sources. Most Long Island plants are fueled by natural gas.
The other half of bills is the delivery charge, which has been frozen for three years as a result of Gov. Andrew M. Cuomo's LIPA Reform Act.
But the delivery charge could see an increase once the freeze is lifted in 2016, depending on how PSEG plans to cover non-fuel costs in its anticipated rate filing next February.