Manila Electric Co. (Meralco) said consumers should brace for a possible slight increase in electricity rates this June, as a potential hike in transmission charges may put upward pressure on overall power costs.

“We are still waiting for all the final billings from our suppliers for the computation of power rates for the June billing period,” Meralco said in a statement on Thursday.

The utility noted that “initial information shows a possibility of an increase in the transmission charge due to a possible uptick in reserve market prices for the May supply month in comparison with the previous month based on publicly available data.”

Reserve market prices determine the cost of ancillary services provided by the transmission grid operator, which is ultimately passed on to consumers.

Meanwhile, generation charges, which make up the bulk of monthly electricity bills, are expected to remain stable.

“We hope it remains flattish and that there will be no significant movement for the June billing month following the significant decrease last May,” Meralco said.

“Should there be any increase, we hope that this could be mitigated by lower prices from the Wholesale Electricity Spot Market as announced by the spot market operator,” it added.

Meralco also pointed to the continued implementation of the P19.96-billion refund approved by the Energy Regulatory Commission, which it said could help offset possible increases in power bill components.

In May, households saw lower electricity bills after Meralco cut rates by P0.7499 per kilowatt-hour, bringing the rate down to P12.2628 per kWh from P13.0127 in April, ending three consecutive months of increases.