Energy cost for shipping food is minor

Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

Ellen Goodman’s syndicated column for July 3rd introduced us to Roger Doiron.  Doiron belongs to a group called “Kitchen Gardeners.”  According to their web site:

“Kitchen Gardeners are a special breed. They are self-reliant seekers of “the Good Life” who have understood the central role that home-grown and home-cooked food plays in one’s well-being. By seeking an active role in their own sustenance, they are modern-day participants in humankind’s oldest and most basic activity, offering a critical link to our past and positive vision for our future.”

Dorian, also works with the Eat Local Foods Coalition of Maine, a group of…

“organizations and individuals interested in creating a shift towards a locally-based food system that is economically vibrant, environmentally sustainable, and healthy.  To some, food system reform may not seem like a pressing social need. But food issues play a dominant role in a range of critical social issues, including poverty, hunger, corporate power, misuse of workers, loss of community, and environmental degradation. With each food purchase decision, consumers are — wittingly or not —making powerful choices that will determine the kind of future we live in.”

Kitchen Gardeners and the Eat Local Foods Coalition seem to have several laudable goals, but saving energy by avoiding the burden of shipping foods over long distances to consumers is a dubious one.  Goodman tells us of the lawn sign, shown below, in Doiron’s lawn that expresses their concern.

I have heard frequently from people promoting farmer’s markets, local agriculural, and those opposed to large scale agribusiness, that food shipments are a significant energy drain and a major source of those pesky greenhouse gases.  Therefore, the argument goes, we should all be eating locally grown food.  Let’s put this argument to the test.

First, let’s accept Doiron’s claim that “in Maine the average person’s food travels about 1,500 miles from field to grocery store using up about 400 gallons of gas.”  1,500 miles and 400 gallons of gas would be a lot to have a single pizza or head of lettuce delivered.  I assume what Doiron really means is that produce, meat, canned foods, etc. usually travel by loaded semitrailers, which get about 4 miles to the gallon  when loaded.  So Doiron is correct, 1,500 miles would take somewhat less than 400 gallons (1,500 miles / 4 miles per gallon = 375 gallons).

A typical maximum weight of a semitrailer on a US highway is 80,000 pounds.  Being conservative, we can say that 60,000 pounds represents the net weight of the product being shipped.  60,000 pounds is a lot of pizza or lettuce.  If the typical person eats 2 pounds of shipped food per day, then that 400 gallons of gas has brought food to 30,000 people! Or, each gallon of gas has brought food to 75 people.  (60,000 pounds / 2 pounds per person / 400 gallons  =  75 people per gallon)

I like to think in terms of kilowatt-hours.  The energy content of one gallon of diesel fuel is equivalent to about 40 kilowatt-hours.  So, if a gallon of gas brings food to 75 people, that is about a half of a kilowatt-hour per person.  The total energy consumed per person per day in the US is about 250 kilowatt-hours (see calculation, below*).  Consequently, the half kilowatt-hour used to ship food 1500 miles to one person is about 1/500th of that person’s total daily energy consumption.

Put another way, if a single $5 gallon of gas delivers 2 pounds of food 1500 miles to 75 people, then the shipping cost per person is a puny 7 cents.  That sounds like a bargain to me.

Let’s not forget the huge social benefits to having enough to eat, the variety of fresh foods available to us outside the local growing season, and the ability to smooth out the effects of local weather extremes on agriculture that are all due to the shipping industry.  I am sure gardening has many benefits, but saving the energy and cost of shipping is not one of them.  Criticism of our great system of food delivery because of a slavish adherence to a “green” lifestyle is simply unfair.

******************************************************************

* The total energy consumed per person per day in the US is about 250 kilowatt-hours.  This may surprise many people.  This number is derived by dividing the total yearly energy consumption of the United States by 365 days and dividing again by the population (300,000,000 or 3e+8 people).

According to Lawrance Livermoor National Laboratory, the total energy consumed in the US in 2002 was 97 Quads.  One Quad is 293,000,000,000 kilowatt-hours, or 2.93e+11 kWh

97 Quads  X  (2.93e+11 kWh/Quad) / 365 days / 3e+8 people = 259 kWh/day/person

.