Some Food For Thought About Using Food For Fuel
By Scott Kriner, Green Metal Consulting
On the surface, the concept of using our food crops for fuel may sound crazy. But with environmentalists worried about the pollution and emissions associated with burning fossil fuels, we are turning to more bio-based fuel supplements. And ethanol produced from our corn crop is the poster child for bio-based fuel used in the transportation industry.
Corn is our country’s number one field crop. But statistics show that only 12% of the US corn crop ends up in our food supply. In Iowa, 55% of that state’s corn crop goes to foreign markets. And roughly 35% of the nation’s corn harvest is used for ethanol production. Some scientists note that the more efficient crop to use as a source for bio-based ethanol is sugar cane, but politics have played into the choice of corn.
So we are indirectly burning some of our food crop as fuel. Is this sustainable? Some would say no. But this is not the end of the discussion on using food for fuel.
What about all of the food that is wasted and could be used for fuel? A study by the EPA estimated that Americans generate roughly 30 million tons of food waste each year, which is about a quarter of the country’s food available for consumption. This amount of waste also represents 12 percent of the total waste stream. All but about two percent of that food waste ends up in landfills. And as that food rots, it produces methane, a major source of greenhouse gases. In fact, in terms of greenhouse gases methane is more than 20 times more damaging to the environment than CO2 gas.
Wasted food comes from the grocery store, restaurants, cafeterias and households every day. It works out to about one pound of food wasted every day for every American. Fresh produce, milk, grain products and sweeteners make up two-thirds of the waste.
OK but what does this have to do with fuel? Some innovative technology now allows for the food waste to be diverted from landfills and used instead to help produce electricity. One of the main ingredients needed for this process is generated by our nation’s cattle industry – manure. Manure of course emits methane gas too. It is estimated that the average cow emits 300 quarts of methane daily. But a good portion of the methane emitted by cows is from manure itself. What if we could put the manure to good use and utilize food waste at the same time? That is exactly what one company is doing.
The Somat Company, an Illinois Tool Works Company, promotes technology that reduces waste with pulping and de-watering systems. They have pioneered these systems for foodservice waste in schools, colleges, hospitals, cruise ships and other large volume food establishments. While attending a regional CSI conference I had the opportunity to learn more about the use of this technology at a university located in the middle of Lancaster County, PA – otherwise known as Amish country.
A system was installed in the university’s kitchen that basically takes food waste and grinds it into a pulp. Equipment then separates the water from the solids. The water is recycled for process uses and the solids are shipped in bulk to a liquid manure processor. The dried food waste material is then dumped into liquid manure tanks. From there the mixed liquid moves into an air-tight digester tank where it is heated to about 100° F. Under those conditions the bacteria in the mixture consumes organic matter and other solids in the manure while releasing methane. The blending of the waste and manure actually increases the methane gas production by 23% compared to pure manure alone. At the Lancaster County site, the methane gas is then captured from the digester tank, piped and burned at a nearby electricity generator. Some of the electricity is used at the university and some is returned to the utility on the grid.
The entire process is sustainable with very little waste. For example, the heat that is generated in the burning of methane is used to heat the barns and milk houses in the winter. The dried waste from the digester stage in the process is used for bedding for animals. Actually the material at that point in the process is sterile which makes that type of bedding healthier for the animals. Some say it contributes to better quality milk for dairy cows.
So next time you scrape food from your plate, or toss that banana into the trash because of one brown spot, think about a better use for our food and what we waste. Our bodies need food as a fuel to give us energy. It’s interesting to see that in some ways our country is recognizing the need for food as a fuel as well.
Scott Kriner is the president and founder of Green Metal Consulting Inc. He is a LEED Accredited Professional who began his career in the metal construction industry in 1981. His company is a member of the U.S. Green Building Council, the California Association of Building Energy Consultants and the Residential Energy Services Network (RESNET). Scott can be reached by email at skriner1@verizon.net or by phone at (610) 966-2430. You can also visit him on the web at www.greenmetalconsulting.com.
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