Medford residents could soon see savings on their electric bills after the City Council approved a proposal by Mayor Stephanie M. Burke to create a municipal energy aggregation program. Such programs allow cities and towns to contract with a supplier to provide power to all residents and businesses at a negotiated rate below what the utility would usually charge. The contract also can provide for some of the electricity to come from renewable sources. Residents who do not wish to participate can opt out of the program. With the help of a consultant who is expected to be hired shortly, the city plans to develop the program over the next few months, according to Alicia Hunt, the city’s director of energy and environment. Once completed, the plan will be submitted to the City Council prior to its submission to the state Department of Public Utilities for approval. If approved, the program is expected to begin this fall.