Arizona’s largest public utility is aiming to give its users a one-time bill credit after it ended up collecting more than needed for energy efficiency and renewable energy programs.

Arizona Public Service Co. is asking the Arizona Corporation Commission to approve what would be an average credit of about $23 per customer at its April 22 meeting.

The money will come from the Environmental Benefit Surcharge on all bills. APS had used the surcharge to fund various projects from weatherization for limited income customers to load management programs that ask consumers to lower their use when power demand is down.

APS has asked to return the money in a one-time refund. The amount of the May credit a customer will receive is based on the customer’s energy usage, so in most cases, if a customer uses more energy per month, they will receive a larger credit. If they use less, it will be a smaller credit, officials said in a press release.