Could food waste power our cities?

Could food waste power our cities?

Summary: Biogas plants convert wasted food into electricity, fertilizer and irrigation water, all while cutting down on greenhouse gas emissions.

TOPICS: Innovation
Harvest Power's Energy Garden in Orlando, Florida

In two giant airtight vats at Harvest Power’s Energy Garden in central Florida, quadrillions of microorganisms are feasting on orange peels, wilted lettuce, burnt bread crusts, and other food discarded by humans. In less than a month, these ravenous creatures consume waste that would have taken years to decompose in a landfill.

Better yet, they release immense amounts of gas — biogas, to be exact. This heady mix of roughly 60 pecent methane and 40 percent carbon dioxide is fed into generators to produce electricity to help power area businesses.

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“A biogas system is a great way to solve a lot of problems,” says Chris Peters, the Harvest Power Regional Vice President overseeing the Florida Energy Garden. “It diverts material from landfills, creates sustainable electricity, and produces useful byproducts in the form of fertilizer and treated wastewater. It’s a win-win.”

Hosted by Reedy Creek Improvement District (RCID), which was created in the 1960s to provide infrastructure services for Walt Disney World and now also serves other businesses in Lake Buena Vista and Bay Lake, Florida, Harvest Power’s Energy Garden was unveiled in February 2014. The facility began by collecting food waste from Walt Disney World’s table-service restaurants and has quickly drawn additional customers in central Florida, where Peters says an average of 24 pounds of food waste is sent to landfills every second.

Harvest is currently processing food waste at a rate of 45,000 tons per year, including 15,000 tons from RCID and 30,000 tons from other sources. This food waste is combined with fats, oils and grease (FOG) and biosolids (treated sewage) for a total of 120,000 tons of organic waste being handled by the plant per year.

Once prepared, the waste is fed into 1.2 million-gallon tanks where anaerobic (meaning without oxygen) digestion takes place. The carefully balanced blend of waste and warm temperatures optimize conditions for the microorganisms to thrive, feed and produce the all-important biogas.

Biogas is released by food waste in landfills too, albeit much more slowly, and most of the methane escapes into the atmosphere instead of being contained. Methane is a harmful greenhouse gas so containing it in a biogas plant has an immediate environmental benefit.

The biogas at Harvest’s Florida Energy Garden creates 27 million kilowatt hours of electricity per year, enough to power 2,300 homes, and is sold to RCID to help keep the lights on at Walt Disney World, among other places. In addition, Harvest sells fertilizer and irrigation water gleaned from the anaerobic digestion process.

Anaerobic digestion is not a new technology. “It’s a microbial process that’s been around since the beginning of time — the same thing happens in a cow’s stomach,” points out Patrick Serfass, Executive Director of the American Biogas Council, founded in 2010 and based in Washington, DC. But biogas facilities are more common in Europe, especially in Germany, because of a shortage of landfill space, high energy costs, and a more favorable political climate for renewable energy alternatives, according to Serfass.

Harvest Energy Garden's material flow. Click on image to enlarge.

Still, Serfass says there have been biogas plants in the US for many decades, mostly at wastewater treatment facilities. What’s new is a focus on using these systems to process some of the 133 billion pounds of food wasted in America each year. Cleanworld in Sacramento recently started a biogas plant that converts community food waste into power for the University of California at Davis. Kroger, the largest grocery store chain in America, processes spoiled food from Ralphs and Food 4 Less stores at a biogas facility to power its distribution center in Compton, California.

Several high-profile businesses near Harvest Power’s Florida Energy Garden have already climbed aboard the biogas bandwagon. Organic produce company FreshPoint Central Florida, produce distributor Taylor Farms, and hotels including the Waldorf Astoria Orlando and Grande Lakes Orlando have all struck deals to send food waste to Harvest Power. 

At the Hilton Orlando Bonnet Creek & Waldorf Astoria Orlando, Managing Director Peter Kacheris says that food waste from all 13 of the complex’s restaurants will eventually be directed to Harvest instead of landfills — plus the complex plans to buy fertilizer byproducts from Harvest for its 18-hole golf course. “It’s cost-effective and also allows us to make a difference through sustainable actions,” says Kacheris, who projects that making the change will reduce the hotels’ garbage bill by about ten percent.

Large-scale diversion of food waste from landfills to biogas plants will require a shift in attitude and behavior on the part of both businesses and consumers, but Serfass says there will come a time when recycling food waste will seem as commonplace as recycling a glass bottle.

“It’s a crime that we have organic waste not being recycled and not being turned into renewable energy,” says Serfass. “We have the technology — we just have to get restaurants and grocery stores and communities to think of this waste as a resource.”

Topic: Innovation

Julie Mehta

About Julie Mehta

Julie Mehta is a writer and editor based in the San Francisco Bay Area. She has written for Travel + Leisure, Parenting, Guideposts,, and She holds a degree from the University of California, Berkeley.

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  • Why is this in a computing magazine

    Don't you have your own magazine somewhere?
    • They did have "their own magazine"

      It was called SmartPlanet. They had a daily newsletter and a weekly summary subscription service. Two weeks ago SmartPlanet migrated their subscriptions to zdnet because they thought that the same smart people who were already zdnet subscribers might also be interested in these more broadly-based, mostly technology-oriented articles.
      I think it was a smart move.
    • SmartPlanet is no longer publishing new content

      CBSi moved the new content to ZDNet. Maybe they thought it would ass some gravitas.

      So far, not so much.
  • Computers, tablets and phones have energy needs

    Computers, tablets and phones when grouped together consume a lot of energy. In many cases, servers of large IT companies can not be completely powered by the electricity grid. Some articles on energies production and renewable energies are welcome.
  • Welcome to the 21st century!

    Here in Switzerland, we don't have enough territory to waste it on landfills, and we don't have any oil or coal. That's why we transform waste into diesel or heath for industrial or private purpose since a long time. Gives us a little independence from the oil nations.
  • This is a FAR better type of "alternative energy" than gasohol

    Corn gasohol uses large amounts of land area to grow corn that could be used for feeding people and causes massive water pollution by fertilizer that produces algae overgrowth in the rivers and dead zones on the coastlines of the oceans. It isn't really even much of an energy source, since nearly 90% of the energy output from gasohol is used to grow, harvest, transport, ferment, and distill it.

    Food waste biogas uses material that has no other use to anyone (except possibly as compost for farming.) It would be nice if there was an efficient way to process household food waste in this fashion. Currently glasses, metals, plastics, papers of many different types are recycled in curbside recycling systems, leaving in some cases less than half the household waste going into the landfill. Most of this is food waste. If the household food waste could be recycled in this way, the remaining waste that cannot be recycled would be very small indeed. The problem is how to separate out food waste from non-recyclable household waste. It is relatively easy to get homeowners to separate out glasses, metals, etc., but it is much less convenient to separate out biological waste. Maybe someone can come up with a way to separate it efficiently after collection, like single-stream recycling of other materials is done.
    • Same place

      It still comes off farm land so has the same impact as growing corn specifically for fuel. The quantities available are also limited and can only be a small supplement. Just think if you could heat your house by burning your food waste. That might last a few minutes a day.
      Buster Friendly
    • Recycling Glasses, metals, plastics

      There IS a technology that has been in use for a few years now. Doesn't use micro-organisms. Can take food waste, metal, plastic, biohazard waste, and turn it into re-usable heating oil, and sanitized water (other usable things also). Think there is a plant next to a Purdue chicken processing plant.
      It is NOT 100% efficient yet, but What is?
  • Unbelievable

    If greater care was taken to prevent this waste altogether, all the other inputs to produce it would amount to much more than what can ever be recovered! This is a secondary solution to primary problem. Only waste that I can accept are the inedible parts of vegetable and fruits like peels and seeds, or what have you.

    What is required is for the world to adopt some of the Jain religion's philosophies and Kerala's rural economic model. World would be much better place.
    • You can do the same with food after it's been eaten

      Organic farmers have been making biogas from animal manure for many years, you can do the same thing with sewage.
  • Why can't you

    just go to the source and use expired people directly as power?

    Tony Burzio