Take a look at a pile of food scraps, and most eco-minded folks think “compost.” And sure enough, that’s a great way to recycle. (Or is it “reuse”?)
In any case, there’s another use for your rotting apple cores and moldering orange peels: Energy. A few municipalities have started setting up facilities to capture the biogas that escapes as organic matter decomposes and turn that gas into energy.
In California, a program at the East Bay Municipal Utility District collects food waste from restaurants and commercial food processors in Contra Costa County (next to Oakland) and San Francisco (which just signed a mandatory composting policy for businesses and residents) and tosses the waste into an anaerobic digester where bacteria break the food down. As they do, up bubble methane and carbon dioxide, which are captured and used to power the utility’s wastewater treatment plant. A similar plan is in the works in nearby San Jose, CA, and other municipalities are looking into setting up similar plants.
Private companies are also getting into the action. A company in England that makes prepared food for Marks & Spencers set up an anaerobic digestion plant to generate heat and electricity at one of its sites. And an onion farm in southern California has been using the juice from its onions to create power for its lighting and refrigerators.
The programs aren’t cheap to get started. The onion farm, for example, says it will be at least five years before it starts seeing a return on its investment. But in the long run, these kinds of systems not only create a new source of renewable energy, they also help cut down on carbon emissions. Discarded food is the second largest category of waste that ends up in landfills. The EPA estimates that we Americans send over 30 million tons of food waste to the dump every year. As it breaks down, that food sends methane into the air. According to the EPA, landfills are the second largest source of human-caused methane in the country.
Best of all, the program doesn’t undermine the composting power of food scraps. The solid waste that’s left over after the gas is captured is still turned into fertilizer for crops.
For more, here’s a nifty video from the EPA, explaining how the process works (2:38).