LIPA customers should expect to pay more for their September bills.

The increase, which will boost the power supply portion of the bill by $6.21, is the second hike in two months. The move follows an increase of $5.71 last month to the same section.

Utility officials blame the move on the higher cost of oil and the heavy use of air conditioning in July. They add that it does not imply a rate hike, but instead a transfer of the cost of power to its customers.