Kelley Coats, customer programs leader for APS, said the prepaid program may not be for everyone. But she expects consumers will like it because it puts them in control. "If their credit balance is low, they can reduce their power usage for a few days."

Jodi A. Jerich, director of the Residential Utility Consumer Office, the state's consumer advocate, supports the prepayment program because it is voluntary and offers incentives that encourage people to use power more wisely. She noted that the program also offers consumers who can't afford utility deposits, ­which are currently $200 or more, another way to get service.

But consumer advocate John Howat, a senior energy policy analyst at the National Consumer Law Center in Boston, said "phantom" fees, such as the $5.95 for credit card payments, add up, especially if someone is paying every week.

Howat said the prepay programs need to do a better job of explaining the risks of cutoffs.

"It is important that elders and others who are considered vulnerable customers be alerted frequently to the dangers of losing their service. Notifications and disclosures are important even before someone signs up for service," he said. "In my view, the materials don't go far enough to describe who are vulnerable or may soon be vulnerable."

Cynthia Zwick, director of the Arizona Community Action Association in Phoenix, objects to the the utility companies describing the prepayment program as an energy conservation program. "If these programs are saving the utility companies money (for billing and unpaid bills), then those savings should be passed on to the customers," she said.

Zwick, whose nonprofit organization helps the poor manage their utility bills and weatherize their homes, said the program "allows the utilities to get their money from customers up front. If people get behind, they are asked if they want to join a prepay program, and, desperate to keep their power on, they opt in. It is coincidental that there is an impact on energy savings."

The APS prepayment program won't use in-home energy monitors like the SRP program, and its customers won't have to go to supermarkets or other vendors to feed a cash machine and recharge their utility cards, Coats said.

APS prepay customers will be able to pay the same way standard customers do: online, by phone, by check or at one of the utility's kiosks throughout its service area. Customers can check their balance online or have it sent to them every day via phone message, text or email. They can choose to be alerted when their credit reaches a specific amount, or it automatically will contact you when it is down to $25.

APS has built in a way for a second person, such as a family member, to receive an email if someone is about to be cut off. It also won't allow anyone with a serious medical condition to participate in the prepayment program.

Also of interest: Are 'smart meters' a good thing? >>

Maureen West is a Phoenix writer