We are solar powered beings. Our bodies run on the solar energy captured by plants. Sometimes that energy is passed through and concentrated (some may say wasted) by animals before it gets to our bodies.
Biologically, we humans are really very energy efficient. Each day we need food containing solar energy equivalent to the energy contained in about a cup and a half of gasoline. The amount of energy an efficient car consumes in about five minutes will keep a human going for 24 hours.
Our bodies consume energy at roughly the same rate as a 150-watt light bulb that is on all the time and give off about the same amount of waste heat as a result.
Of course, until the discovery of fossil fuels, our food system was completely solar powered. Plants, animals, people, windmills and water mills are all powered by current sunlight.
Many of our personal food systems still are largely solar. Produce from a near-by, hand-tended garden, nourished by compost, crop rotations and cover crops is mostly solar powered until we cook or cool it. (Maybe that is why eating directly in the garden tastes and feels so good.)
Over the past century or so, fossil fuels have become an increasingly important ingredient in our food system.
By 1940, every calorie of fossil fuel used in the U.S. food system produced 2.3 calories of food energy.
Today it takes about 10 calories of fossil fuel to produce one calorie of food energy. We use 10 units of fossil fuel energy to obtain each unit of solar energy we consume.
That is an average, of course. Some foods use the equivalent of two and a half gallons of gas to yield just that cup and a half worth of solar energy; thirty calories in for one calorie out. The trends toward longer supply lines, more elaborate processing, smaller packages, more exotic and out of season produce and more food waste all increase energy use.
Indeed, a 2010 USDA report "Energy Use in the U.S. Food System" found that between 1997 and 2002, energy use along the food chain increased at six times the rate of total domestic energy use.
Why is energy important?
Energy use is important for a number of reasons. We've lived through availability concerns and price spikes. The more places in the food chain that fossil fuels are needed, the more ways that changes in energy prices effect food prices.
Even if fossil fuels remain plentiful and cheap as a result of the full scale environmental assault by the energy producers-fracking, Arctic drilling, mountaintop removal, tar sands mining and trash burning for some examples-there are the effects of burning fossil fuels on the environment, especially on the climate.
All the signs point to serious future issues with the greater variability and intensity of weather events because of energy-driven climate change. The more fossil fuels we burn, the more we change the climate. As we change the climate, growing food becomes more difficult, everywhere.
The more energy we consume, the more entropy or disorder we create. Climate change is just part of the entropy we've created by burning fossil fuels. Entropy is defined by the second law of thermodynamics. The second law is one of the fundamental laws of nature and understanding it is critical to our future. See my essay "Lettuce and the Laws of Thermodynamics" for more on this topic.
Energy and Food in Connecticut
As more and more folks in Connecticut focus on the importance of local food, there are many different approaches with different implications for energy use and the environment. This difference was first driven home with two pictures from a state document about preparing for climate change. One picture was of a fava bean and oat cover crop on a Connecticut organic farm as an example of using solar energy to create fertility and manage soil in a way that provides resilience in the face of climate change.
The second picture is the inside of a high tech greenhouse for completely controlled growing. At a cost of a million dollars per acre, these are being touted as an important part of our agricultural future. However there may be important questions to ask about the use of resources including money and energy, about the effects on the environment and about long-term sustainability.
That was several years ago. Now there are folks proposing to grow lettuce under lights in old factory buildings in Bridgeport. (I guess when we start eating that food is when we stop being solar powered beings. Electricity, even with very efficient lights, may not taste so good. From an energy standpoint, this seems fundamentally different from growing mushrooms in old factory buildings in Waterbury.)
Of course others think we'll be printing our food from ingredient tubes in 3-D printers, or perhaps living on pills.
The food production methods we use will have large effects on environmental, human and community health.
Taking full stock of the costs and benefits of various kinds of food systems, it is hard to beat the close-to-home, organic, low-energy, local food system that is emerging in cities and towns, on small and medium size farms and in gardens, at schools, colleges and churches all over Connecticut.
Click here for more on the value of a garden and other local solutions in the face of global food problems.
Now, back to work on our farm, for more local, solar food production.
I appreciate your thoughts.
CT NOFA's Organic Advocate, Bill Duesing, is available to share his expert opinion as a long time organic farmer, founder of CT NOFA, and president of the NOFA Interstate Council. He can come to speak at your event for $300 plus mileage from Oxford, CT. To book Bill Duesing as a speaker, call us at 203.888.5146 or email email@example.com