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Energy cost for shipping food is minor

July 4, 2008

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

.

11 comments

  1. People is not the plural form of person.


  2. Dennis Falgout,

    Thanks for staying on topic. By the way, you are wrong.

    See World WIde Words for a breakdown of the use of people, peoples, person and persons.

    Best Regards.
    Tom


  3. While I think your expose’ is laudable I think you will be hard pressed to find any plant pumping out a ratio of 40 KwH’s per gallon. More like 10-12:gallon. Still, your argument is valid. The organic farmer expends more energy in driving to the seed store, buying fertilizer, grocery store for other items and to the farmer’s market to sell their “faux-gween” items at inflated prices that consumers then have to drive more miles to work more hours to pay for. Sheesh! People spending bucks to save pennies.


  4. You are forgetting that the cost isn’t simply about money. It is also about the amount of green house gases being emitted…


    • Auna,

      Thank you for your comment.

      The fear of CO2 has been taken to an extreme far beyond its worth. Why not go all the way and simply ban any activity that will yield CO2.

      For example, the breathing of a single person will yield more CO2 per day than will the $0.07 worth of gasoline needed to bring him his food.

      Should we all stop breathing?

      Climate Sanity


  5. Interesting article, and point taken.

    I do take issue with some of your numbers, however. An empty semi with a trailer can vary greatly in terms of weight, but most seem to agree that a standard semi full of fuel and without a refrigeration unit weighs at least 30,000 lbs., and they can often weigh as much as 40,000 lbs. You also failed to account for the weight of the product’s packaging, which can be very significant especially with large quantities.

    And, let’s not forget that even though you can conveniently convert a person’s consumption and a diesel’s consumption to the same units (kwh’s), it’s not really apples to apples. Diesels can only consume one thing: diesel fuel, which is a very finite resource and costs a lot of energy to extract and refine (and you shouldn’t brush off the amount of pollution consuming diesel creates).

    No matter how do the math, it will always take less energy to ship food a shorter distance than it does a longer distance.


    • Dear James,
      the numbers are quite simple: 7 cents for a kilogram delivered. You can nibble around the edges of this simple back of the envelope calculation and maybe get it to 8 or 9 cents. But the point remains the same.

      While the profound conclusion that “No matter how do the math, it will always take less energy to ship food a shorter distance than it does a longer distance” is practically a tautological, the cost is still trivial.

      Best regards,
      ClimateSanity


  6. The author of this piece is no better at this issue than the eat local folks, in terms of personal bias and accuracy. There are numerous gross assumptions and inaccuracies in this article. This article is way too simple to give you an honest estimate.

    One that stands out right away is assumption that every truck is filled with 60K lbs of pure food. So that means that wood pallets, plastic wrap, steel wire and cardboard all make it to the dinner table. Another big one is mass density of food. A truck load full of potato chips and bread will not weigh 60K lbs as opposed to a load of coke soda.


    • Dear Skeptical Passerby,

      I think you are a little confused.

      I am curious – What makes you think that I have assumed “that every truck is filled with 60K lbs of pure food?” I neither state nor imply such a thing.

      The article is based on a “back of the envelope” calculations. If you feel better about it, assume that each kilogram of food is accompanied by a kilogram of “plastic wrap, steel wire and cardboard,” a gross over estimation by the way. In this case, the cost of shipping the food is now 14 cents per person per day. Still a tremendous bargain, given all the benefits of access to that food.

      Best Regards,
      ClimateSanity


  7. Fossil fuels are indeed a tremendous bargain. Too bad the sale won’t last forever.


  8. This post is an utter disgrace to the essence of our humanitarian existence.



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