Surging diesel and fuel oil prices are translating into higher prices for electricity users on the Neighbor Islands, where energy surcharges have jumped by at least 50 percent during the past year.

Utility customers are discovering the energy surcharge portion of their bill — the part reflecting changes in fuel prices above a base charge — has more than doubled on the Big Island in the past year, while it has grown 82 percent on Maui.

Kaua'i's residential customers are paying 34.2 cents per kilowatt hour compared with 28.6 cents a year earlier as a result of the increased surcharge.

"My bill went up 10 percent in the past couple of months," said Moloka'i resident Curtis Crabbe, an electrician who's seen his residential bill jump from $95 to $105 in two months. "That's $120 a year."

Hawai'i's electrical bills have jumped as the cost of oil crept higher during the past year. Local utilities are allowed to pass on the increases above a set amount, resulting in higher electricity bills. The most recent increase came as the average U.S. wholesale diesel prices crept higher, reaching a high of $2.78 a gallon on October 19. That was more than double what it was at the start of the year.

At the Kaua'i Island Utility Cooperative about 50 percent of the fuel used in nine generators is diesel, said Joe McCawley, Kaua'i Island Utility manager of regulatory and legislative affairs.

He said electricity prices rising at a time when gasoline prices were falling under the state's wholesale gas cap has provided for some lively discussions with customers, McCawley said. Diesel fuel isn't regulated under the gas cap law and its price reacts to different market factors, he said.

"It's a very popular question these days," he said.

Average residential utility bills have risen statewide in the past 12 months and include: