Savings Through Energy Productivity Act, or the STEP Act - Directs the Secretary of Energy to establish the STEP Emergency Rebate Program (STEP), under which the Secretary makes grants to eligible utilities to pay the costs of providing rebates or credits against the amounts of electric bills of customers that reduce the amount of electric energy consumed.

Establishes the STEP Fund in the Treasury. Instructs the Secretary to establish a program making no-interest loans to utilities and nonprofit organizations to pay up to 100 percent of the cost of an energy productivity project. Requires an annual accounting by loan recipients.