In a plan that would drastically remake New York City’s skyline and shores, Mayor Michael R. Bloomberg is seeking to put wind turbines on the city’s bridges and skyscrapers and in its waters as part of a wide-ranging push to develop renewable energy.

The plan, while still in its early stages, appears to be the boldest environmental proposal to date from the mayor, who has made energy efficiency a cornerstone of his administration.

Mr. Bloomberg said he would ask private companies and investors to study how windmills can be built across the city, with the aim of weaning it off the nation’s overtaxed power grid, which has produced several crippling blackouts in New York over the last decade.

Mr. Bloomberg did not specify which skyscrapers and bridges would be candidates for windmills, and city officials would need to work with property owners to identify the buildings that would best be able to hold the equipment.