Residential electric rates rose on Oahu in August from July in part because of higher fuel costs, Hawaiian Electric Co. reported Monday.

Elsewhere around the state, power bills this month rose on Hawaii island but fell on Kauai and in Maui County.

The bill for a typical household on Oahu using 600 kilowatt-hours of electricity a month is $210.14 in August compared with $204.27 in July, according to HECO.

The residential rate on Oahu rose to 33.5 cents per kilowatt-hour in August from 32.5 cents per kilowatt-hour in July. The July rate was lower than the same month last year, when residential customers on Oahu paid 34.5 cents a kilowatt-hour.

The increase in the rate on Oahu was partly the result in an increase in the price for low-sulfur fuel oil, which is burned to generate most of the electricity consumed on Oahu, according to a HECO spokes­man. HECO also collected more from customers as part of its reconciliation of actual versus estimated costs for electricity it purchases from independent power producers, the spokes­man said.

The reliance on oil for power generation is one of the primary reasons electricity in Hawaii is three times the national average. Hawaii residents paid an average of 37.1 cents a kilowatt-hour for electricity in May compared with the national average of 12.1 cents a kilowatt-hour, according to the latest data available from the U.S. Energy Information Administration. Washington state, which is one of the nation’s leaders in hydropower, had the lowest electric rate at 8.7 cents a kilowatt-hour.

Topping the state in August was Kauai, where residents paid 41.6 cents a kilowatt-hour for electricity, down from 42.3 cents a kilowatt-hour in July.

Hawaii island’s residential rate rose to 39.4 cents a kilowatt-hour from last month’s 39.2 cents. The typical bill rose to $247.13 from $245.57.

Maui Electric Co. customers saw their rate decline to 35.9 cents per kilowatt-hour from 36.1 cents per kilowatt-hour last month. The typical Maui bill fell $1.35 to $224.13.