An ordinance co-authored by Supervisor Sophie Maxwell, whose district includes the plant, and Supervisor Michela Alioto-Pier, would make it city policy to "take all feasible steps" to close the plant, located in the Potrero district and owned by Mirant Corp.
The ordinance would also establish clean energy goals for the city.
City officials have been seeking to close the Potrero power plant for years. In 2006, they successfully shuttered a similar plant in neighboring Hunters Point.
Residents in the area have blamed the power plants for environmental damage and higher incidences of health problems.
According to the proposed ordinance, recent and planned transmission upgrades in San Francisco and the Bay Area may be enough to convince state regulators that the Potrero power plant is no longer needed to maintain the reliability of the electrical grid.