Over the coming days, we'll be sharing material from Chapter 4 (Energy) of the latest Resilience guide, "Rebuilding the Foodshed: How to Create Local, Sustainable & Secure Food Systems". This is a heck of a chapter, one that takes a look at the complex relationships between food systems, energy and waste. If you eat food, grow food, use energy, create energy, or make waste, you'll find yourself fascinated.
Read Part 2, Read Part 3, Read Part 4, Read Part 5, Read Part 6, Read Part 7
Food is energy. Food provides energy. Food requires energy. Food and energy are virtually synonymous. They even share a common unit of measure. But that doesn’t mean that they are in balance. To the contrary. And nowhere is that imbalance more evident than in the United States.
As soon as one opens wide and espouses the need for a food system that’s balanced in terms of health, equity, and ecology, it becomes apparent that much of the discussion is about how to extract one’s ecological footprint from one’s mouth. The problem is that, in terms of energy, our ecological footprints are estimated to be somewhere between seven and ten times the size of our mouths. In other words, it takes seven to ten calories to produce and deliver the equivalent of a single calorie of food in the United States.1 These food system calories eventually add up to an estimated 19 percent of America’s total energy consumption.2 (It is important to note here that we typically measure calories in our diet as a “small calorie,” the amount of energy needed to raise one gram of water one degree Celsius. When we measure energy on a larger scale, we call it a “kilocalorie” or a “large calorie” and denote it with a capital C, as in “Calorie,” since it is defined as the amount of energy needed to raise one kilogram of water one degree Celsius.)
Do we simply go retro? Techno? Heck, no. A total historical reversal to preindustrial conditions is just as unlikely as a technological absolution for our modern-day petroleum-based gluttony.
The energy behind human civilizations was once a product of the food supply. But we are at a point in human history in which food is predominately a result of nonhuman energy inputs. The prospect of bringing food and energy closer to a one-to-one ratio of calories invested to calories derived is extraordinarily complex, and it has direct links to the call for creating more sustainable and resilient food systems. Today in the United States, these food and energy questions comprise a quandary that most of us can ponder in relative comfort, without the imminent threat of being unable to feed ourselves due to costs, energy constraints, or shortages. And yet, even as we relish the extraordinarily low cost of food in the United States, certain threats do lurk in the background. The energy supply that feeds our food system is at short-term risk of disruption by natural disasters, international conflict, and economic turmoil. The long-term impacts of worsening climate change, dwindling petroleum supplies, and increasing global population pressures are looming realities that we may try to ignore but ultimately cannot avoid. We have already seen how spikes in food prices can create social unrest with the seeming velocity of the flick of a match.
Such inquiries into food security should not be viewed as mere intellectual exercises or myopic self-preservation interests. Perhaps the most compelling reasons to grapple with our precarious food/energy imbalance are sheer justice and altruism.3 People who are “food insecure”4 are generally far too busy trying to convert their own personal energy into food dollars to spend much time researching and thinking about the national food and energy dilemma. The onus is upon those who are concerned enough to care and are able to do something about it. As actor Alan Alda once said during a graduation speech to a group of medical students, “The head bone is connected to the heart bone—don’t let them come apart.”5
I am an optimist and a good-natured (I hope) skeptic. But from my vantage point as a farmer and an academic, few things worry me more about the human condition than the intertwined fragilities of our food and energy supplies—and our habits that exacerbate the amount of energy consumed between farm and fork.
I struggle to make sense of the food/energy dilemma most every day, although I would by no means characterize those days as gloomy or my attitude as morose. Rather, my days tend to be filled with sunshine, pastoral landscapes, solar panels, healthy livestock, laughing children, and inquisitive students. But the energy-to-food ratio is a constant theme, starting with the morning milking on our off-the-grid farm. Our grass-fed herd of American Milking Devon cattle get either fresh pasture or good-quality hay every morning—no grain, but plenty of gain. The milk pails are washed with solar-heated hot water while the early morning lights in the house are powered by yesterday’s sunshine. (We are almost entirely solar-powered, with fossil-fuel backups providing about 20 percent of the additional energy we need.) We’ll use one of our two Kubota tractors to do the morning’s heavy lifting or towing, but the goal is to use them as little as possible and, when feasible, not at all.
When the chores are completed, by me or often by one of our apprentices, I admittedly leave home in a gas-guzzling four-wheel-drive vehicle and head out sixteen miles to my job at Green Mountain College, where I oversee the college’s Farm & Food Project. As I pull up, students are usually walking to and from the farmhouse and the various outbuildings that comprise the college farm complex, often toting milk pails or vegetable bins as they wrap up morning chores there. Their farm—and it is theirs in many ways—is much like mine at home, an experiment in trying to minimize energy inputs and maximize food output. However, their work is more rigorous in its analytical aspects, thanks to the research oversight headed by my colleague Kenneth Mulder, one of the few PhDs in the United States who is also an expert at using oxen in agriculture.
The farm’s focus is to probe ways toward a food system that eschews fossil fuels as much as possible—and indeed, all of the activities on the farm seem to orbit the question of our overblown American diet. Draft animal equipment, photovoltaic panels, a solar hot water system, greenhouses, ergonomic hand tools, and bike tractors dot the farm. Students’ experiences with these techniques and technologies contrast sharply with the predominant realities of our current food system, which has us guzzling kilocalories of diesel energy in our tractors and gorging on excessive calories of food energy from our kitchens.
My favorite view from my office window in the second floor of a restored farmhouse is the summer scene of the oxen cutting and bringing in the hay for their winter ruminations. Other days, I gaze out the window and watch Kenneth and the students work in the vegetable fields that are his research plots. He has divided the vegetable production into three plots, each powered by a different system (see fig. 4-1). The easternmost section is cultivated, planted, maintained, and harvested exclusively by human power and the use of highly efficient hand tools. The middle section relies upon a combination of human power and a BCS walking tractor, essentially a highly versatile tiller with a variety of implements ranging from a sickle bar mower to a potato harvester. The western plot catches the most attention, as it is the market garden section powered primarily by the oxen and their accoutrement of fancy new (yes, generally new, and also quite efficient) tillage equipment.
This research project, dubbed LEAFS (Long-Term Ecological Assessment of Farming Systems), is Kenneth’s brainchild, a means of evaluating all of the energy inputs and outputs within each system. The goal is to develop a database of ten years of experimentation in order to discover the energy requirements of each system and to assess its efficiencies and challenges.
One of the more amusing aspects of it all is watching students work with stopwatches and scales in order to monitor their own energy inputs and each plot’s productivity. Even the energy expended by the oxen in pulling different pieces of equipment is measured by means of a dynamometer, a device placed between draft animals and any load that they pull as part of a task on the farm. The dynamometer sends a signal to a computer in the oxen-driver’s backpack, indicating precisely how much energy the oxen are exerting every second. This information is then transferred to a Google Earth map so that the oxen energy can be recorded both in joules (a unit of energy) and on a map that details the different levels of energy expended on certain tasks and in specific locations.
Efficiencies can also be measured in a variety of ways. For this long-term ecological study, Kenneth has opted to analyze efficiency in terms of labor, land, and energy, and his figures are based on wholesale organic vegetable prices (see table 4-1). It is interesting to note that the energy efficiency (measured as energy return on energy invested, or EROEI) of all four calculations ranges from 2.3 to 7.0, which is significantly higher than the range of 0.26 to 1.6 that is typical for conventional vegetable production in the United States.6
Trade-offs are inevitable in farm management systems, but seldom do aspiring farmers get to test out the practicalities of different systems, much less measure them with the sophistication provided by Kenneth’s expertise. The most elusive variable is energy, but it is arguably the one that currently warrants the most scrutiny.
The farm is the natural starting point for rectifying the imbalance between inputs and outputs, but if we are truly seeking balance in our food system, we must also assess the basic energy parameters that frame our daily decisions as consumers. In doing so, most of us gravitate immediately to the production and distribution aspects of our food system. Granted, those are critical components to tackle. However, food production and distribution often seem a bit beyond the scope of control for the average person, and—somewhat contrary to our recent intense focus on food miles—the transportation portion of our energy diet is actually relatively small in comparison to other parts of the food system that are based upon and driven by consumer choices and household habits.
As it turns out, the elements of the food system most within our control often tend to be those parts of the system that are closest to home, and they are also among the most energy-consumptive components found between farm and fork. The food and energy decisions we make in and near the home have the greatest impact on our personal energy-to-food ratios (see fig. 4-3).7 Household storage and preparation represent the largest single sector of energy use in the entire food system. When it comes to energy issues and food systems, “local” starts to become quite personal.
In order for the food and energy dilemma to really hit home, so to speak, it helps to remember that every step in the farm-to-plate process increases total energy inputs, making food waste an issue that we can ill afford to toss casually aside. As we work our way through the food chain, it will become increasingly obvious why reducing waste is such a critical link in creating resilient local food systems.
1. Martin C. Heller and Gregory A. Keoleian, Life Cycle-Based Sustainability Indicators for Assessment of the U.S. Food System, report no. CSS00-04 (Ann Arbor: University of Michigan Center for Sustainable Systems, December 6, 2000), 42.
2. David Pimentel et al., “Reducing Energy Inputs in the U.S. Food System,” Human Ecology 36 (July 15, 2008): 459.
3. It is important to note here that I also think it imperative that we consider the plights of those persons well beyond our local and national borders. The point here is that it is often easier to begin the caring process when there are direct and proximate relationships. "Local," in my view, is a starting point for caring—not an endpoint of any sort.
4. “Food-insecure” populations include persons who have limited or uncertain access to nutritionally appropriate foods.
5. Alan Alda, Things I Overheard while Talking to Myself (New York: Random House, 2008), 47.
6. David Pimentel and Marcia H. Pimentel, Food, Energy and Society (New York: CRC Press, 2008).
7. For more information on the number of calories expended in producing a single calorie of food in the U.S. food system, see Heller and Keoleian, Life Cycle-Based Sustainability Indicators. More information on this topic can also be found in Richard Heinberg and Michael Bomford, The Food & Farming Transition (Sebastopol, Calif.: Post Carbon Institute, Spring 2009), http://www.postcarbon.org/report/41306-the-food-and-farming-transition-toward.
'Rebuilding the Foodshed: How to Create Local, Sustainable & Secure Food Systems' is book three from Post Carbon Institute's ongoing series of Resilience Guides.