The borough assembly voted unanimously Tuesday to approve an electricity rate hike that will increase the kilowatt-hour charge by 7.5% to 9% for most residential and business customers in Wrangell.

The rate increase comes after the Southeast Alaska Power Agency, which provides Tyee Lake hydroelectric power to Wrangell, Petersburg and Ketchikan, notified the borough in early December that it would increase its wholesale power rate by a quarter-of-a-cent per kilowatt-hour, from 6.8 cents per kWh to 7.05 cents.

The borough’s increase in retail rates will take effect Jan. 20; customers will s...