September marks the fourth month in a row that Oahu residential customers will need to put a little extra toward their electricity bills.

The bill this month for a typical household using 600 kilowatt-hours went up from August by 78 cents to $218.96, according to data released this week by Hawaiian Electric Cos., the state’s largest utility provider with service to Oahu, Maui and Hawaii island.

Rising fuel costs were the reason for the rate increase on Oahu, HECO spokes­man Peter Rosegg said.

"The slight increase in the typical bill this month is due to the price paid for fuel, which Hawaiian Electric passes through to customers with no markup," he said.

Reducing customer rates was one goal HECO outlined in the plans it recently filed for Hawaii’s energy future with the state Public Utilities Commission. Lowering customer rates by 20 percent, giving customers more service options, nearly tripling distributed solar and more than 65 percent of state energy coming from renewable sources by 2030 were some of the goals proposed by the utility when filing the plan in August.

"Our energy environment is changing rapidly, and we must change with it to meet our customers’ evolving needs," said Shelee Kimura, Hawaiian Electric vice president of corporate planning and business development, after the filing. "These plans are about delivering services that our customers value. That means lower costs, better protection of our environment and more options to lower their energy costs, including rooftop solar."

Customer rates remained a key focus for the utility in September when HECO named Alan Oshima as the new chief executive officer.

"We need to move away from a traditional utility model to become a responsive, affordable energy services provider for our customers, and I’m confident Alan is the right leader to guide our utility through this transformation," said Connie Lau, chairwoman of HECO and president and CEO of its parent company, Hawaiian Electric Industries Inc., when announcing HECO’s change in leadership.

On Oahu the September rate rose to 35 cents per kilowatt-hour from 34.9 cents a kilowatt-hour in August, when the typical bill was $218.18.

HECO, its sister utilities in Hawaii and Maui counties, and the Kauai Island Utility Cooperative adjust their rates monthly to reflect changes in their fuel costs and the prices they pay for electricity purchased from independent power producers.

Hawaiian Electric Cos. has more than 450,000 residential and commercial customers, with 300,000 on Oahu, 70,000 on Maui and 80,000 on Hawaii island. KIUC is a member-owned cooperative that serves 33,000 customers.

Neighbor island bills in September were all lower than the previous month.

Maui Electric Co. customers this month are paying 37 cents a kilowatt-hour, down from 37.3 cents last month. The bill for a household using 600 kilowatt-hours of electricity is $230.46, down from $232.12 in August.

Hawaii Electric Light Co.’s residential rate on Hawaii island decreased to 40.8 cents a kilowatt-hour from 42 cents a kilowatt-hour in August. The bill for a household using 600 kilowatt- hours of electricity is $255.20, down from $262.36.

On Kauai, meanwhile, the rate this month is 41.2 cents a kilowatt-hour compared with 42.1 cents in August. The bill for a household using 600 kilowatt-hours of electricity is $247.20, down from $252.60.

Average monthly kilowatt-hour usage varies by island, but the 600 kwh number is used for comparative purposes.

HECO rates are tiered where residents using less electricity pay a lower rate than people using the midrange or a lot of electricity.

The price of electricity in Hawaii is nearly three times the national average in large part because of the high cost of fuel oil used for power generation.

Hawaii residents paid an average of 38.66 cents a kilowatt-hour for electricity in June compared with the national average of 12.97 cents a kilowatt-hour, according to the latest data available from the U.S. Energy Information Administration.