Geothermal plants and rooftop solar panels are also options, said the billionaire mayor, whose second and final term ends in January 2010. He gave companies until Sept. 19 to submit innovative proposals toward the mayor's broad goal of making the city greener by 2030.

Bloomberg, an independent who has pushed into the national sphere with gun-control and infrastructure plans, faulted politicians for "treating us to a political silly season" and "pandering" to voters instead of solving the energy crisis, which he called the nation's top issue.

Calling a carbon tax the only measure that will work "corruption free," he added: "Some want a cap-and-trade system, which is like taking three right turns instead of one left."

Last week marked the fifth anniversary of the black-out that deprived 50 million people in the Northeast and Canada of electricity, Bloomberg noted. The country must play "catch-up" he said, citing estimates that producing 20 percent of US electricity by 2030 with wind power will require US$60 billion of spending on transmission infrastructure.

New York City also will soon push private building owners into conserving electricity. New laws and regulations will require energy users to receive more information about the "real value" of conservation. "And they'll also require cost-effective retrofits of our existing larger buildings," he added.

(Reporting by Joan Gralla; Editing by David Gregorio)