Avista Corp., of Spokane, is requesting a rate increase for electricity customers in Washington state. 

If approved, the monthly bill for a typical residential electricity customer would increase by $2.55 a month, to $123.41 from $120.86 monthly, starting July 1. That represents a 2.1% increase in a typical customer's bill. 

For Avista, the rate hike would generate an additional $15.3 million annually. 

The company states in a press release that it's seeking the rate increase to cover certain deferred power-supply costs. 

The rate hike is pending approval from the Washington Transportation and Utilities Commission and follows news earlier this week that the company has reached a settlement agreement on a proposed rate increase for natural gas customers in Oregon. 

Avista provides electricity service to 422,000 customers and natural gas service to 383,000 customers in parts of Washington, Idaho, and Oregon.