Meeting the Challenge of Peak Oil
With Sustainable Agriculture
Higher prices for gasoline and other fossil fuels have renewed public interest in alternative sources of renewable energy, including wind, water, photovoltaic, and bio-fuels. Energy prices in 2005 were due in part to unpredictable events, such as hurricane Katrina, but the approaching peak in global oil production makes even higher energy prices both predictable and inevitable. Peak oil is a concept based on the premise that peaks in oil production occur when approximately half of the total amount of oil in a particular oil field has been extracted, which typically occurs some 30-40 years after the initial discovery. Beyond that point, extraction becomes increasingly difficult and costly and total production inevitably declines.
Peak oil gained credibility when U.S. domestic oil production peaked in 1970, thirty-plus years following the peak in U.S. oil discoveries in the 1930s. The peak in global oil discoveries occurred later, in the mid-1960s, signaling a peak in global oil production around the turn of the twenty-first century. Changes in extraction methods and uncertainty regarding Middle East oil reserve data have made precise calculations difficult, but most forecasters now place the year of global peak oil somewhere between 2006 and 2010. Even more optimistic government forecasts indicate a peak in global production between 2010 and 2015, with a 70% decline in total oil production by 2050. If major new oil fields were discovered next year, which is highly unlikely, those fields would not reach peak production for another 30-40 years. The world quite simply must learn to live with less oil.
A transition to biological energy sources is not the solution. The renewable energy produced annually by all types of plant life within the U.S. amounts to only about two-thirds as much as total annual U.S. use of non-renewable fossil energy. Agriculture is able to harvest only a little more than 35% of total plant energy produced – an amount equivalent to about 25% of total U.S. fossil energy use. Total energy used by U.S. agriculture amounts to an equivalent of about 6% of total fossil energy use. This might appear to indicate a significant energy surplus for agriculture. However, crops that could be consumed directly by humans account for only about 20% of total agricultural energy production. The remaining 80% is produced by pastures and forages, which are utilized by livestock in producing meat, milk, eggs, and other food products. In addition, about 90% of all food crops produced in the U.S. is fed to livestock and poultry, which on average require more than 15 kcal of fossil energy for each kcal of food products. As a result, U.S. agriculture actually uses about three kcal of fossil energy for each kcal of food energy produced.
In addition, agriculture accounts for only about one-third of total energy used for U.S. food production, including food processing and distribution, the total being equivalent to about 17% of total fossil energy used. The U.S. food system in total requires approximately 10 kcal of fossil energy to produce each kcal of food energy, in addition to the solar energy harvested by agricultural plants. Agriculture alone cannot possibly produce enough bio-fuels to offset the future decline in fossil fuel production. In fact, agriculture faces a formidable challenge in producing enough renewable energy to meet the growing global food and fiber needs.
Shifting to a vegetarian diet would be one obvious means of reducing energy use in agriculture, since most food crops are net energy producers, possibly cutting the food energy input/output ratio in half. However, energy used and lost in food processing and distribution would still leave about a five-to-one net fossil energy deficit for total food production. In addition, the 20% fossil fuel equivalent produced by pasture and forage plants – large net energy producers – would be lost. Shifting from confinement livestock feeding operations to grass-based operations could be a more logical means of reducing the energy used in animal agriculture. A shift to grass-based systems could save an estimated 35% of total energy now used in beef, dairy, and lamb production.
Other sustainable farming practices could reduce agricultural energy use still farther. For example, research based on more than 20 years of recent data indicates that shifting to organic farming practices could save as much as 30% of the fossil energy, without reducing total production. Sustainable grass-based livestock systems, utilizing management intensive grazing, are capable of producing from 50% to 100% more protein per acre than conventional pasture/forage systems, while using less fertilizer, pesticides, and fuel. Free-range and pasture-based pork and poultry also are far more energy efficient than confinement feeding operations. In addition, hogs and chickens are natural scavengers and thus could get a significant portion of their diets from waste products. Significant fossil energy savings from livestock and poultry might well be achievable without sacrificing healthy levels of animal protein in human diets. Changes in food processing and distribution in the U.S., such as increased use of raw and minimally processed foods, more meals prepared at home, and a shift to more community-based, local food systems, could increase the efficiency of energy use in food marketing by comparable amounts.
To my knowledge, no detailed estimates are available, but energy savings from shifting to more-sustainable agricultural systems, using currently available methods and technologies, probably could cut total fossil energy use in agriculture by one-half, resulting in a savings equivalent to about 3% of total fossil energy use. Similar efficiencies in processing and distribution could save an additional 6% or so in fossil energy use, but would still leave total food production with an energy deficit equivalent to 8% of current total fossil energy use in the U.S.
Despite the current enthusiasm for biological sources of renewable energy, it seems unlikely that agriculture of the future will be able to produce more energy than will be needed to meet the increasing food and fiber needs of people. Current agricultural energy initiatives, specifically those utilizing grain and oilseeds to produce ethanol and bio-diesel, have shown little promise of ever generating significantly more energy than they consume. Their primary value seems to be in changing the form of energy, to provide fuel for motor vehicles, rather than increasing the total amount of energy available. With a growing world population, reducing the amount of fossil energy required for food production would seem a far higher public priority than turning potential food for hungry people into fuel for automobiles.
Farms may have far more to contribute in meeting future energy challenge as locations for wind generators than as producers of energy crops. Current estimates indicate that wind energy could eventually replace up to 60% of current fossil energy use. However, achieving this level of production would require large investments in energy transmission infrastructure in addition to thousands of wind turbines. Wind energy advocates are currently promoting the development of huge wind farms populated by dozens to hundreds of multi-million dollar generators. However, such initiatives reflect the industrial-era thinking that created the energy problem, rather than a sustainable energy paradigm for the future. A sustainable energy system must be able to realize the benefits of specialization, standardization, and consolidation of control, but without sacrificing the diversity, site specificity, individuality, and decentralization necessary to maintain the capacity for renewal and regeneration.
On sustainable farms, wind turbines would be integrated into the overall farming operation, utilizing a diversity of sizes and strategic locations to accommodate other farming activities. On large, specialized wind farms, turbines occupy about 2% of land area. On sustainable farms, the competition for space between generators and farming would be insignificant. Smaller turbines in less concentrated patterns at many different locations might be less technically efficient, but would minimize potential noise pollution and other environmental concerns and would prevent the tremendous concentration of economic and political power that otherwise will be associated with energy generation in the future. Supplemental income from energy generation would also help diversity and sustain large numbers of small to moderate sized farming operations. Sustainable energy will require ecological integrity and social responsibility as well as economic efficiency.
A sustainable wind energy system likely would be a decentralized network, linking hundreds of thousands of farms and ranches with various numbers and types of wind generators. Windmills would be scattered across the North American West and Great Plains as well as other specific areas with wind energy potential. The same transmission lines bringing electricity to these farms and ranches could be used to carry wind-generated energy back to the major retransmission points within the network. Such a network would also allow farmers to help close energy cycles on their farms by utilizing plant and animal wastes to generate electricity. However, such a system would require a fundamentally different type of infrastructure and organizational paradigm from that envisioned for giant, specialized wind farms.
In meeting the challenge of peak oil, we must not allow agriculture to be viewed with the same industrial mind-set that has made the global economy so completely dependent on fossil fuel. Ultimately, we must embrace a material standard of living that will allow unavoidable losses of nonrenewable energy to be offset by energy captured by living plants, windmills, falling water, photovoltaic, and other sources of solar energy. To meet the challenge of peak oil we must respect the rights of those of future generations to meet their energy needs as we find ways to meet ours, not just find another source of cheap nonrenewable energy to last through our lifetime. A sustainable agriculture can help, but meeting the peak oil challenge ultimately will depend on the willingness of human society to embrace the ecological, social, and economic principles of sustainability.
Most energy percentages used are based on data from, David and Marcia Pimentel, ed., 1996, Food, Energy, and Society, University Press of Colorado, Niwot, CO.
 Sustaining People through Agriculture series,” Small Farm Today Magazine, Missouri Farm Publications, Clark, MO. November-December 2005.