Mayor Michael Bloomberg has proposed a renewable energy program for New York city that would include placing windmills on city bridges, solar panels on skyscrapers, and the use of tidal, geothermal and nuclear energy.

Bloomberg unveiled the outlines of his plan late Tuesday at a major clean energy summit in Las Vegas organized by the University of Nevada.

"Just five years ago last week -- on August 14th, 2003 -- this country got an object lesson in how big a gamble we're taking with our future if we don't change course," said Bloomberg, referring to the giant blackout that cut off power for 50 million people across the northeastern United States and Canada.

Hundreds of people were rescued from high-rise elevators, and thousands more were rescued from stalled trains in the city's subway system.

"We learned that this time, the enemy was us and our failure to take care of our infrastructure," he said. "The world's greatest nation was shown to have a power grid that was seriously over-strained and out-of-date."

Bloomberg said he is determined to keep the city's energy usage at or near its current level even as the population grows. But the city has to increase production of clean energy, he said.

"I believe that we've got to be willing to do what some other nations -- such as France -- have already done, and increase our capacity of safe and clean nuclear-generated power," he said.

Clean energy projects could also "draw power from the tides of the Hudson and East Rivers -- something we're already doing on a pilot basis," he said.

Bloomberg proposed increasing rooftop solar power production, "which we've estimated could meet nearly 20 percent of the city's need for electricity."

Companies may also "want to put windfarms atop our bridges and skyscrapers, or use the enormous potential of powerful off-shore winds miles out in the Atlantic Ocean, where turbines could generate roughly twice the energy that land-based windfarms can," he said.

Bloomberg urged businesses to submit proposals for his ideas by September 19.