Renewable Fuels Act of 2005

Renewable Fuels Act of 2005 - Amends the Clean Air Act to direct the Administrator of the Environmental Protection Agency (EPA) to establish a program to require U.S. motor vehicle fuel to contain a certain volume of renewable fuel. Defines "renewable fuel" to include cellulosic biomass ethanol, waste derived ethanol, and biodiesel.

Establishes a system of: (1) tradeable credits for motor vehicle fuel containing more renewable fuel than required; (2) waivers for states and small refineries; and (3) safe harbor standards to protect manufacturers of renewable fuels from civil liability.

Amends the Energy Policy Act of 1992 to require federal agency heads to ensure that ethanol-blended gasoline and biodiesel-blended diesel fuel are purchased for agency vehicles in areas where such fuel is available at competitive prices.

Amends the Clean Air Act to eliminate the oxygen content requirement for reformulated gasoline.

Requires the Administrator: (1) to establish standards for toxic air pollutants from the use of reformulated gasoline; and (2) within 30 days of enactment of this Act, to determine the adequacy of any petition from a state governor to exempt gasoline sold in the state from certain requirements for reformulated gasoline.

Directs the Administrator (currently, discretionary) to require fuel manufacturers to conduct tests to determine potential public health and environmental effects of fuels and fuel additives prior to registering such fuels.

Permits states in the ozone transport region to opt into the reformulated gasoline program.

Requires the Administrator, at the request of a state, to enforce state controls on fuel and fuel additives.

Sets forth various data collection and reporting requirements.