SCOTT SIMON, HOST:
Holidays can mean a lot of leftovers, but excess food is an issue around the year. It's estimated that the amount of food wasted each year in the United States could fill the tallest skyscraper in Chicago more than 40 times. That could rival the music library of BJ Leiderman, who writes our theme music.
As part of a collaboration with the PBS NewsHour, NPR's Allison Aubrey reports on ideas to tackle the food waste problem, including an initiative in Massachusetts where farmers are using wasted food to create green energy.
ALLISON AUBREY, BYLINE: At a time when 30 to 40% of all the food that's produced never makes it to our mouths, some grocery chains are doing their part to cut back on waste. At the Whole Foods in Shrewsbury, Mass., there's a system in place to make sure none of the surplus is tossed in the trash.
KAREN FRANCZYK: We do have items that we can't sell, either because they're spoiled, items that are bruised.
AUBREY: That's Whole Foods' Karen Franczyk. She's taken us to the back of the store where an industrial masher called Grind2Energy gobbles up everything that would be wasted.
FRANCZYK: And you can imagine, there's everything from bones - we put whole fish in there, vegetables. You can have dry items like rice or grains.
AUBREY: There are watermelon rinds and wilted greens. Whole Foods donates the surplus food that it can, but there's a lot left over. And the grinder turns all these bits into a slurry.
FRANCZYK: So it really becomes kind of a liquefied food waste.
AUBREY: From here it's loaded into the tank of a truck. And you ready for this? It will be used to make electricity.
FRANCZYK: There's no question it's better than putting it in the trash.
AUBREY: When food is left to rot in a landfill, it releases methane, a potent greenhouse gas that contributes to climate change. A recent report from the United Nations finds that up to 10% of all human-made greenhouse gas emissions are linked to food waste. But there are workarounds to prevent this from happening. A company called Vanguard Renewables has installed systems on five dairy farms in Massachusetts to capture all this methane. One of them is in the town of Deerfield.
PETER MELNIK: So my name is Peter Melnik, and I'm a fourth generation dairy farmer.
AUBREY: On the day we visit, he shows us what is basically a mini power plant on his farm.
MELNIK: Behind us is an anaerobic digester that makes methane that we turn into electricity.
AUBREY: In addition to all that food waste from Whole Foods, he gets truckfuls (ph) of whey from a Cabot Creamery as well as waste from a local brewery and a juice plant.
MELNIK: We presently take in about a 100 ton, which is about three tractor-trailer loads every day.
AUBREY: In the digester tank, he mixes all of this together with his cow manure, which cooks at about 105 degrees. And as the methane is released, it rises to the top of a bubble-shaped dome.
MELNIK: We capture the gas in that bubble, and then we suck it into a big motor. It's about the size of your car. And that engine runs on methane instead of diesel or gasoline. And that in turn is turning a big generator, which is then creating 1 megawatt of electricity.
AUBREY: This powers all of his farm and home and much more.
MELNIK: We only use about 10% of what we make, and the rest gets fed onto the grid. And it's almost enough to do 1,500 homes.
AUBREY: He says times are tough for dairy farmers, so this gives him a new stream of revenue. And he says it's good for the environment, preventing the release of methane into the atmosphere.
MELNIK: The digester has just been a really - a home run for us. It's made us more sustainable environmentally, but also economically as well.
AUBREY: The CEO of Vanguard Renewables, John Hanselman, says he hopes to expand the operation.
JOHN HANSELMAN: There is more than enough food waste in Massachusetts to feed all of our five digesters plus many more.
AUBREY: Massachusetts passed a law that prohibits big food manufacturers and businesses from sending their organic waste to landfills, and this has created an incentive for them to participate in the waste-to-energy initiative. But Hanselman says his hope is that this concept will spread. He points to Europe, where there are thousands of anaerobic digesters.
HANSELMAN: Food waste recycling through anaerobic digestion could be done in every part of the country. There is literally nowhere where you couldn't do this.
AUBREY: The company is currently building an anaerobic digester on a farm in Vermont. And the gas produced there will be piped to Middlebury College, which will help the college reduce its carbon footprint. Allison Aubrey, NPR News.
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