NEW YORK – New York's Mayor Michael Bloomberg has proposed putting 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.

“In New York, we don't think of alternative power as something that we just import from other parts of the nation,” he said.

The mayor says he will approach private companies and investors to study how 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 in the city.

“We want their best ideas for creating both small- and large-scale projects serving New Yorkers,” Bloomberg said.

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 dependance on a power grid that caused several large blackouts in the past decade.

Major obstacles to the technology include neighborhood opposition to the windmills; the high cost of building and running them; and a host of permits that would be needed from state and federal agencies.

But the mayor said offshore turbines could be placed “as much as 15, 20, 25 miles offshore, where it's virtually invisible to land.”

Smaller eggbeater-like models could be used on rooftops. “You can make them so small that people think they are part of the design,” Rohit Aggarwala, director of the city's Office of Long-Term Planning and Sustainability, told The New York Times.

Aides to the mayor said Bloomberg has met with oil investor T. Boone Pickens to discuss how wind power could be used in New York City. Pickens has proposed building the world's largest wind farm in Texas.