Arizona Public Service customers may notice a difference in their bill this month.

The company is lowering consumers’ charges by an average of $3 per month, because of a number of factors — including solar power it exchanges with California. The change kicked in Friday, Feb. 1. This billing reduction will continue through 2019, said Jill Hanks, spokesperson for APS.

The reason why it is an average of $3 and not a set price is because of the reduction’s dependence on the energy usage of the customer, she said. For example, customers who use more energy will see a higher reduction while customers who use less energy will see less of a discount.

Dawn Carnley, a Prescott resident, currently pays APS bills of about $40 to $50 each month. She is delighted the bills are going down; however, she is wary about the reasons for the changes.

“Usually things go up and not down, so you know a few bucks is a few bucks,” Carnley said. “A few bucks can buy vegetables and sprouts. As long as there are no shenanigans behind it that I don’t know of, because like I said there is always a balance, a reason, why they are lowering prices,” she is OK with it.

Several factors went into APS lowering its billing rate:


APS exchanges power, including solar power, with California through the company’s participation in the Energy Imbalance Market, which is run by the California Independent System Operator. The power company has a power trading floor, filled with around-the-clock workers who buy and sell power from other utilities.

When California has an excess solar energy, it sometimes pays other utilities to take the energy off the California system. APS likes seizing on the opportunity when California begins offering its power. “We like to maximize those and pass it along to our customers,” said Kerri Carnes, APS manager of State Regulations.

For example, Hanks said, California paid APS to take excess energy for 81 days this past year.

Since participating in the Energy Imbalance Market, APS has saved customers and the company $75 million, APS spokesperson Suzanne Trevino said, adding that APS saved $45 million last year through the EIM.

The parent company of APS, Pinnacle West Capital, spent $37.9 million to fight a clean-energy proposition last year that was rejected by voters.


Each year APS files adjustments to the “power supply adjust,” which is what APS pays for power plant fuel and power from other utilities. Customers find the PSA as a line item on their bill, which is dependent on the natural gas and other power plant fuels markets. If those costs go up or down, then the PSA will also increase or decrease. When operating costs are less — or less than what APS projected to pay — the company distributes the money, lowering the cost for customers, Carnes said.

In March 2018, APS was able to make a reduction of about $10 per month for customers because of an adjustment to the PSA, Hanks said.


At the end of 2017, Congress passed and President Trump signed the Tax Cuts and Jobs Act of 2017. APS was one of the first utility companies in the nation to take advantage of the tax cuts, Hanks said. She said the money saved from the tax cut was also passed along to customers.