Greenburgh Town Supervisor Paul Feiner suggested Wednesday that windmills be added to the Tappan Zee Bridge.

Feiner?s idea comes on the heels of New York City Mayor Michael Bloomberg?s plan to put windmills on city bridges and rooftops as part of an ambitious push for renewable energy. Bloomberg outlined his plan Tuesday night at a Las Vegas conference on alternative energy.

Energy-producing wind farms are already in use in Rockland County. For more than eight years, the state Department of Transportation has studied the aging Tappan Zee, which has had a history of structural problems.

At some point in the next five years, Feiner says the bridge is expected to be either overhauled or completely rebuilt. Tarrytown resident John Zambrano favors Feiner?s idea, but says that issues such as traffic management and cost need to be considered carefully.

"If it's planned out right and it's effective and aesthetically it doesn't affect the essence of the Hudson Valley, then why not?" Zambrano says.

It would take years to turn New York City into a major source of wind power. But Bloomberg, who has 18 months left in office, says he is committed to getting the discussion going with the aim of reducing the city's dependence on a power grid that caused several large blackouts in the past decade.

Bloomberg says he will approach private companies and investors to study how such turbines can be built throughout the city. On Tuesday, the city also issued a formal request to companies around the country for ways to build wind, solar and water-based energy sources.