PSEG Long Island in August will again raise the power supply charge portion of electric bills, increasing the average billby around $10 as the cost of fuel and power are affected by heat and rising demand.

For this month, the power supply charge will jump to 8.3484 cents a kilowatt hour, up about 18 percent from the 7.0480 charge in July. Since January, when the charge was at a record low 5.27 cents, the charge has increased some 58 percent. PSEG has said the January figure was “artificially low,” because the company, as required, was returning overcollections from 2015 in that month.

August will be the sixth straight month with an increase, although year to date the average power supply charge of 6.56 cents is lower than in the prior two years, according to a Newsday analysis of the figures. The average for 2014 was 9.4 cents and in 2015, it was 8 cents.

“While we understand no one likes to hear about an increase in their bill, PSEG Long Island has worked to reduce the month-to-month volatility and stabilize these charges,” spokesman Jeff Weir said.

The increase set for the August supply charge was also affected by the utility’s need to recoup undercollections from June and July, when the charge was set to projections that ended up below actual fuel and power costs, he said. This August’s charge is a 23.2 percent increase from the charge in August 2015 of 6.77 cents a kilowatt hour.

Power prices tend to rise in higher-demand summer periods, increasing the cost of power from spot markets and for fuel, PSEG said.

PSEG prices have also been affected this summer by the utility’s activation of so-called peaker power plants around the Island during recent heat waves, using generally more expensive power. Peaker plants use fuel oil or natural gas to produce power at high-demand times in the summer.

advertisement | advertise on newsday

It’s not just the power charge that’s going up. This month, PSEG said the decoupling charge portion of bills would jump in September to $4.30 a month for average customers, from the current $1.69 a month. The charge allows the utility to recoup costs when green energy, weather and other factors lead to reductions in collections. The adjustment can also return money to customers if the utility’s costs are lower than projections.

PSEG and LIPA last year, as part of their rate-hike request, also were given the ability to adjust bills up or down if debt refinancing costs, union contract negotiations and power supply contract costs fluctuate in a given year.