ANOTHER REASON TO APPRECIATE VEGETABLES

mayor michael bloomberg has floated some pretty eye-catching ideas for reducing air pollution, such as wind turbines in our harbor and congestion pricing on our streets. meanwhile, the most effective way for new york to combat global warming would be to replace some of the petroleum-based heating oil used in the city with fuel made from vegetable matter. this idea may not be so glamorous, but it does have the virtue of being completely practical and virtually costless.

this winter, new yorkers will use some 475 million gallons of diesel oil as heating fuel. this oil is highly polluting, and it increases our dependence on middle east suppliers.

obviously we have to heat our buildings. but there's a better way.

over the past two decades, scientists have figured out how to make perfectly good heating oil from vegetable matter-they call it "biodiesel." while boilers in use today wouldn't run well using pure biodiesel, they can use a blended fuel containing up to 20 percent biodiesel (and 80 percent conventional heating oil) with no loss of function.

(don't confuse biodiesel, which is soy- or palm-based, with ethanol made from corn. ethanol is costlier than biodiesel and much less beneficial environmentally. what's more, ethanol requires the destruction of corn crops, while biodiesel allows 80 percent of each producing plant to be used for food.)

replacing 20 percent of the city's heating oil with biodiesel would have enormous benefits for the environment, eliminating more than 700,000 metric tons of carbon dioxide per year. to put that in perspective, the congestion pricing plan would have eliminated only 240,000 metric tons.

biodiesel makes economic sense, too. at various times over the past year, biodiesel has actually been cheaper than regular heating fuel. and as the science gets better, this green fuel will become even less costly.

the truth is that biodiesel isn't just a dream for pie-in-the-sky environmentalists. the new york home heating oil association supports the use of biodiesel, and a few forward-thinking companies are already selling it here in new york. in fact, the city government has even begun using biodiesel to heat some of its own buildings. to achieve mainstream conversion to biodiesel, however, the energy sector will need a prod from the government. private companies have been reluctant to invest in biodiesel production for fear that new demand is only temporary. but industry experts agree that the prospect of supplying the enormous new york city market would certainly stimulate production-and would likely drive the price of biodiesel down.

to that end, i have introduced legislation in the city council that would require heating oil retailers to begin phasing in biodiesel blends, beginning with a 5 percent blend next year and working up to a 20 percent blend by 2013.

let's make this the last winter that new york relies so heavily on petroleum oil for heat. the city council should pass biodiesel legislation as soon as possible. -- david yassky is a city council member from brooklyn and a candidate for comptroller. he grew up on the upper west side