Higher costs for wind power in April increased the bills for electric utility customers on Maui.

Typical Maui Electric Co. customers saw a $7.03 increase in April from March, as the average bill for a Maui household using 500 kilowatt-hours is $155.35, or 29.1 cents a kilowatt-hour. In March, the bill was $148.32, or 27.7 cents a kilowatt-hour.

Hawaiian Electric Co. spokeswoman Shannon Tangonan said Wednesday the Maui utility’s purchase of power from wind facilities, instead of the utility-owned fossil fuel plants, caused the April bills to increase.

“In March, the proportion of wind energy used to generate electricity on Maui was about 25 percent. In April, it’s 41 percent,” Tangonan said. “Right now the cost of wind energy is higher than the cost of oil-generated electricity. In months when the proportion of wind energy increases, as it did in April, the Maui bills may increase.”

The prices MECO pays for wind coming from the three facilities on Maui — Kaheawa Wind Farm I, Kaheawa Wind Farm II and Auwahi Wind Farm — are a result of previously negotiated 20-year contracts approved by the state Public Utilities Commission. Under the terms of the contract, the electric utility has to buy the wind energy available.

The average price for MECO’s oil-powered plants is about 13 cents a kilowatt-hour in April, Tangonan said. The average price for wind energy on Maui is about 19 cents a kilowatt-hour.

Customers on Oahu also saw their April electric bills rise, but slightly.

The bill for an Oahu household using 500 kilowatt-hours rose 19 cents to $143.45, or 26.6 cents a kilowatt-hour, compared with $143.26 and 26.6 cents in March. April’s modest increase makes the sixth month in a row the island has seen bills rise.

Tangonan said higher fuel prices caused the Oahu increase.

Electricity rates in Hawaii are more than double the national average, as Hawaii residents paid an average of 28.32 cents a kilowatt-hour for electricity in January. The national average was 12.22 cents in the same month, according to the latest figures from the U.S. Energy Information Administration.

The state’s high rates have been largely attributed to Hawaii’s dependence on imported oil for most of its power plants. The state spent $5.4 billion on petroleum in 2014, according to the EIA. In April 2014, the typical 600-kilowatt-hour bill on Oahu was $212.05. HECO has since lowered what it considers typical household usage to 500 kilowatt-hours from 600 to reflect reduced customer energy use.

In 2015, HECO’s energy mix was roughly 71.1 percent oil on Oahu. HECO imports oil primarily from Southeast Asia and the Middle East. Other states use a combination of energy resources such as natural gas, hydroelectric power, coal and nuclear power.

Customers on other islands saw electric bills decrease in April.

The residential cost for typical Hawaii Electric Light Co. customers on Hawaii island in April is $164.31, or 30.5 cents a kilowatt-hour. This month’s bill was $2 lower than March, which was $166.31, or 30.9 cents a kilowatt-hour. Out of all of HECO’s territories, the Big Island has the highest percent of renewables in its energy mix at 54 percent.

Customers on Molokai and Lanai also paid lower bills in April compared to March. The two islands are included in MECO’s territory. Renewable energy makes up 36.9 percent of Maui, Molokai and Lanai’s energy mix.

MECO customers on Molokai using 400 kilowatt-hours of electricity are paying an average of $138.59, or 32.2 cents a kilowatt-hour. In March, the bill was $140.61, or 32.7 cents a kilowatt-­hour.

Lanai residents using 400 kilowatt-hours of electricity are paying $143.06, or 33.3 cents a kilowatt- hour. In March, the bill was $143.21, or 33.4 cents a kilowatt-hour.

Bills on Lanai and Molokai are calculated based on a typical household using 400 kilowatt-hours of electricity in a month. This is due to lower energy use compared with Maui, Hawaii island and Oahu, HECO said.

HECO, MECO and HELCO monthly bills include the cost for kilowatt-­hours used, plus other charges.

Outside of HECO’s territories, Kauai Island Utility Cooperative’s typical bill for a household using 500 kilowatt-hours in April, including a $10.58 customer base charge, dropped to $171.33, or 32.15 cents a kilowatt-hour. In March, the bill was $175.93, or 33.07 cents a kilowatt-hour.