I mentioned in passing some time ago that I was going to start tracking our food waste by separating it from the trash stream, recording its weight, and putting it aside for compost. While I don’t yet have a proper compost bin, or even plans for a garden, I wanted to get going on this end of the project not only to get a start on material for our garden, but also to get a look at how much food we end up throwing away, and how much energy and money are embedded in that wasted food. A recently published study by Amanda Cuellar and Michael Webber at the University of Texas shows that the United States loses as much as 2000 trillion BTUs of energy every year due to food waste, roughly 2% of the nation’s total energy use.
(I think I’ve written about this before, but I can’t seem to find the post now. Oh, well.)
There seems to be a huge opportunity for savings here, but one that would require a substantial re-tooling of the national and global food system. The intuitive response might be to focus on food-miles as the leading culprit, but the numbers tell a slightly different story. According to the study, food transportation comes in a distant second to food handling in energy consumption, 1690 to 3880 trillion BTUs. In another report using different methodology to answer a different question, Patrick Canning and his team at the USDA estimate that “energy flows associated with the commercial transportation of food represent less than 5 percent of total energy use by the overall food system.”
These findings have some implications for the local foods movement, which I’ll consider soon enough. For now, I want to focus on our micro-scale experiment and what it might mean for us in savings of energy, money, and time.
I set up a high-tech collection and weight-recording system:
and began tracking what we were throwing out. I didn’t count scraps that went to the dogs, because I counted them as being eaten. It was a fairly simple matter to fill, weigh, and tally the can before transferring the contents to a larger bucket on the back porch. This first week, we diverted 10 pounds of food waste from the trash. How does that affect the world? Well, 10 pounds per week would be 520 per year; for us, roughly 100 lb. per person. Multiply that by the 300 million people in the US and that would be 15 million tons of garbage kept out of landfills and incinerators; 15 million tons of organic matter returned to the earth to make topsoil. Not bad.
Financially, less trash to throw out means a lower bill for us.These are the rates we’re charged by the city disposal service:
|10 Gallon Can (Micro Can)||$10.21|
|20 Gallon Can (Mini Can)||$12.08|
|32 Gallon Can (Regular size can)||$14.84|
|68 Gallon Can (or 2 garbage cans)||$20.56|
|95 Gallon Can (or 3 garbage cans)||$26.28|
We need to do some unit conversions here:
The 10 lbs. of food waste filled a 12″x10″x9″ bucket with a volume of ~1080 cubic inches. This site here informs me that 1 gallon takes up 231 cubic inches, so that 10 lb. of compost is roughly 4.675 gallons. That could easily be enough to reduce a family’s can size from one category to the next lower one, and indeed that was the case with us. We went from the 68-gallon (2 can) level down to a single 32-gallon can, saving $6.55 per month(rate difference of $5.72 per month and taxes of $0.83 at14.5%). That’s $78.60 per year off the top, never mind what we might save in groceries if we can use the compost to grow herbs and vegetables this year. It looks like easy money for the little effort required.
We will have to wait and see how this translates specifically to reduced money and energy spent on buying and hauling food this summer, as I’m sure there will be other start-up costs involved in setting up our garden, but it looks like an encouraging start with some immediate returns.