Residential electricity rates on Oahu rose to the highest level in 2 1/2 years in May as rising fuel prices pushed up generation costs for Hawaiian Electric Co.

HECO said  a typical 600-kilowatt-hour bill for Oahu residential customers rose to $188.88 in May from $181.44 in April.The last time Oahu electric bills were this high was in November 2008, when a 600-kilowatt bill was $182.01.

Crude oil futures were $115 a barrel on May 1, about 35 percent higher than they were six months earlier. Crude oil futures traded at a record $147 a barrel in the summer of 2008.

The effective rate for electricity in Honolulu is 30.1 cents per kilowatt-hour in May, up from the 28.9 cents last month.
Elsewhere in the state:

• Maui Electric Co. customers saw rates rise to 35.9 cents per kilowatt-hour this month from April’s 34.1 cents. The typical Maui bill rose by $10.68 to $223.21.

• Big Island residential rates rose to 42.40 cents a kilowatt hour from last month’s 38.2 cents. The typical bill rose by $25.55 to $265.96.

• On Kauai, the rate rose to 44.27 cents per kilowatt-hour. Last month, the rate charged by the Kauai Island Utility Cooperative was 42.63 cents per kilowatt-hour.