(Photo by Will Stone - KJZZ)

APS faced backlash over its demand charge proposal after filing its rate case last year.

It's only a week since Arizona Public Service asked to raise rates and add a new charge to customers’ bills — and already backlash has begun.

On Tuesday, clean energy groups gathered in downtown Phoenix holding signs like “Surge Pricing Is Unfair” and “Profits Over People” to protest the utility’s proposed “demand charge.” That would be based on the one hour during 3 p.m. and 8 p.m. each month when a customer uses the most power.

“They’re confusing. They’re difficult to plan for and can cause our utility bills to skyrocket,” said Sandy Bahr with the Sierra Club.

Bahr said households will be slapped with big, unexpected fees if they accidentally turn on too many appliances one evening. But APS argues the new charge will actually give customers another method of saving money by staggering their energy use and other parts of the bill, like the cost of energy, will go down.

More than 100,000 APS customers already use demand charges.

Traditionally, demand-based rates are reserved for commercial and industrial customers.

Bill Mundell, a democrat running for the Arizona Corporation Commission, said the APS proposal is unprecedented.

“It’s never been mandated on residential consumers in the United States and it appears to be just another way to raise revenue for APS,” said Mundell.

APS argues the rates better reflect the costs of providing power during peak hours.

If state regulators approve the APS rate plan, customers would also see a rate hike of about 8 percent beginning in July of next year.