Food processing facilities are beginning to look like potential early adopters of waste-to-energy recycling.
Because they are large single-point generators of food scraps, which have more energy content than sewage and some other organic materials, as well as being large consumers of energy, food processors are well-positioned to surmount some of the obstacles to implementation of anaerobic digestion reactors to turn food into electricity and gas.
The topic is an important one. According to the Environmental Protection Agency (EPA), food is the largest single component of the material that goes into landfills or is converted to energy, representing 21 percent of the total. About 35 million tons of food waste reaches landfills and incinerators each year in the U.S., according to the EPA.
Processing is a major generator of that food scrap. Food scrap generated by processing accounts for 23 percent of total food losses, including those contributed by distribution, retail operations and households, according to the Natural Resources Defense Council (NRDC), citing a European study. Food manufacturers lose about 16 percent of raw materials during manufacturing, NRDC said.
Adoption of waste-to-energy by food processors is “very important” to encourage broader acceptance of the technology in the United States, according to Brandon Julian, CEO of Pure Energy Group, a Park City, Utah maker of anaerobic digestion reactors that create energy from organic materials. “The amount of waste they produce in day-to-day operations is pretty dramatic, and anaerobic digestion is a very good environmental and business solution for them,” Julian said.
So far, adoption of anaerobic digestion for converting scraps from food processing into energy is rare in the United States, especially compared to Europe. However, a combination of regulatory limits on landfilling organic waste and government financial supports for waste-to-energy facilities suggests that may change soon. “There is extreme growth potential in this country for it,” Julian said.
One of the best examples of a food processor converting waste to energy is Gills Onions, an Oxnard, California onion grower and processor. Since 2009, the company has converted up to 300,000 lbs. per day of onion peels and other processing leftovers into renewable energy and cattle feed.
Juice extracted from Gills’ peels feeds an anaerobic reactor that produces biogas that powers two 300-kilowatt fuel cells. The cells generate $700,000 worth of electricity annually to power a processing plant, while remaining pulp becomes cattle feed cake. The company saves another $400,000 annually by not having to haul waste to fields, where it was formerly added to soil. The company said it will recover the $10.8 million cost in 6 years.
Potato processors are good candidates for waste-to-energy because processing yields as much as 50 percent of the potatoes as scrap. One potato processor that has gone this route is Belgian company Remo-Frit. Its anaerobic digester turns 3,300 cubic meters of peels and other scrap into biogas each day, providing energy to operate refrigerators and other machinery.
Anaerobic digestion is far more common in Europe than in the United States, in part because energy costs are much higher there than in the U.S. Also, in Europe government financial support of waste-to-energy is much more significant.
Another issue in the U.S. is reluctance by utilities and pipeline companies to allow waste-to-energy generators of electricity and biogas to connect to their grids so companies can sell excess energy from waste, according to Julia Levin, executive director of the Bioenergy Association of California. Grid owners set up stringent standards for waste-to-energy generators that few have been able to meet, Levin said. “It’s been virtually impossible to connect to the pipeline grid,” she said. That is why some of the more appealing customers for waste-to-energy facilities are large food processors who can use the energy to power their own operations.
Without revenues from selling generated energy, however, the cost of waste-to-energy facilities makes it impractical for many applications. Costs range from about $500,000 for Pure Energy’s smallest system up to as much as $500 million for some large municipal facilities that will handle food waste as well as sewage and other organic materials, including those from curbside collections.
Government financial subsidies can help cover the economic gap for potential waste-to-energy users. “In most cases that is very valuable or necessary to make them pencil out,” said Julian, although he said that without subsidies their systems can generate break-even return on investment in as little as three to five years, depending on location and cost of energy in local markets.
Another factor encouraging waste-to-energy is the spread of laws requiring generators of food waste to stop sending their materials to landfills. A number of states, including Connecticut, Vermont and Massachusetts, as well as cities including San Francisco, Seattle and Portland have banned commercial food waste from landfills.
Pending legislation in California will similarly restrict large generators from sending food scrap to landfills, Levin said. And that should motivate additional interest in waste-to-energy. “For food processors, the larger ones are going to be regulated,” she said. “They’re going to have to do something with food waste if they’re large producers of food waste.”
Processors that turn scrap into energy save on landfill tipping fees and can potentially generate additional revenue from sales of energy, “It can go from a net cost to a net revenue generator,” Levin said.
For now, most large food waste-to-energy installations in the United States are municipal facilities that mix food scraps with sewage and other organic waste. A few pioneers in food processing are continuing to push the envelope, however. Gills, for instance, recently installed a battery array to store electricity created from its waste-to-energy process.
In the not too distant future, many more food processors are likely to join the waste-to-energy movement, driven by rising energy costs and the opportunity to turn a by-product into a cash source. “They also understand they’re not going to be able to keep putting organic waste into landfills that much longer,” Levin said. “So they’re taking steps to get ahead of the curve.”
Published in the August 2014 Edition of American Recycler News