The nation’s largest pre-pay metering system is about to set another record as it connects its 50,000th customer to the increasingly popular M-Power service. Salt River Project, which provides electricity to over 890,000 customers in the Phoenix area, introduced its M-Power program in the early 1990s.

The service was primarily targeted for lower-income or credit-challenged customers, but has gained popularity among its general residential customer base.

The M-Power program works much like a pre-paid phone card; customers can purchase “smart” cards which allow them to pay for their electricity use ahead of time. The “smart” cards can be reloaded at more than 50 service centers throughout the Phoenix area, or by mail. The card is then inserted into a dsiplay unit (which is provided to the customer in a start-up kit) in the home, and the energy purchase is transferred to the home system.

In addition to avoiding late fees, deposit fees and bills, the M-Power program allows customers to closely monitor their electricity use. The in-home display unit shows not only the amount of electricity consumed in kilowatt hours, but also in dollars.

According to the Salt River Project, M-Power customers report an 84% satisfaction level with the program, and 91% say that the program helps them use energy more efficiently.