Column: Fuel is used many ways in food supply

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By John Bartlit

A global issue in its infancy is the fuel demand of the food supply. The issue sprang on the public scene with the fuel demand of growing corn to make fuel.

I have no answers but I bring useful questions. Most issues have too many answers known and too few questions asked.

The corn-ethanol question is simply figuring the input and output. How much fuel energy is in the ethanol made versus how much is needed to make it from corn?

The input energy is the sum of the fuel energy to till the soil, plant the corn, fertilize it, harvest it, truck it to an ethanol plant and convert it to fuel. The issue goes on but for now, the net gain in fuel energy looks small at best.

The broader question is what food supply system demands the least fuel energy. An aspect people focus on is the fuel used to transport food. Fuel demand is less to bring us melons or meat from nearby than from far-off Chile or New Zealand.

Is this still true if melons come 100 per truck from two hours down the road versus how many hundred thousands per shipload, plane-, train- and big truckload from Chile? I would guess so but to know takes more figuring.

What if melons come from Arizona in a mid-sized truck? What if the melon patch, or the farmland, requires pumping lots of water to grow melons?

As you can tell, I know nothing about melon farming. The little I know about any farming I learned from crossing paths with agriculture majors at Purdue. But you see the engineering point.

Food supply is a system with many parts. Steps include soil preparing, planting, maybe watering, fighting bugs and frost, harvesting and shipping. Processing may be another step, as well as heated or cooled storing.

The fuel demand of the food supply is the sum of the fuel used in all steps, not just shipping.

Many factors affect the total fuel use. Climates vary in ways that raise or lower fuel demand. Differences can be in soils, rainfall, frost, bugs, the warmth of days and nights – even agriculture schools.

Consider a case.

In distant New Zealand, good rainfall and moderate temperatures make grass fill the land as relentlessly as sunup. Too bad grass is not as tasty as melons – except sheep think it much better.

In New Zealand’s climate, sheep can be wholly pasture-fed. Commercial lamb is produced without farm-grown feed.

Steps that are avoided are soil preparing, planting, watering, harvesting and shipping of feed. Nature does as much for free. The related fuel use is saved. Reports say, “More than 50 percent of New Zealand’s export earnings come from a low-cost agriculture based entirely on grass.”

Again, I don’t know big answers but I know to ask about many parts.

Consider another case.

Some of our food supply comes from greenhouses. Greenhouses can be heated by natural gas, by geothermal or solar energy. Some are in New Mexico.

Say I buy a peck of tomatoes trucked 100 miles. How much total fuel is consumed if the peck was grown outdoors, in a gas-supported greenhouse or in a solar-heated greenhouse?

How much fuel is used per peck sold from a small local farm or if supplied from a large geothermal-heated greenhouse 300 miles away?

Answers take some figuring.

The fuel needed to supply food is not a short story. Food systems have multiple steps. Fuel may be used and saved in any of them.

Nature’s diversity of climates impacts fuel use in ways we may not guess. The same goes for nature’s capricious locations of resources.

For better or worse, the effects of fuel on the supply and cost of food are complex.

The answers are to be found throughout the system.

John Bartlit is the member of New Mexico Citizens for Clean Air and Water.