From the production of fertilizers to the processing and transporting of food products to market, the industrial food system depends on fossil fuels to produce monocultures of commodity crops. Increasingly, food crops are being diverted to energy production — most notably corn, which is being used to make ethanol as a fuel. Industrial agriculture’s present reliance on finite energy sources that negatively impact the natural environment is not sustainable. There are energy alternatives at every step along the process that can help our food system become more resilient.
Energy has always been essential for the production of food. Prior to the industrial revolution, agriculture’s primary energy input was the sun: plants grew naturally from photosynthesis and then served as food for livestock, which in turn provided fertilizer (manure) and muscle power for farming. With the adoption of farm machinery, synthetic fertilizers and other modern technologies, food production has become increasingly reliant on fossil fuels, such as synthetic nitrogen fertilizers, petroleum-based agrochemicals and diesel-powered machinery.
Around the beginning of the twentieth century, farmers began to use tractors instead of horses. After World War II, cheap fossil fuels in combination with more powerful and specialized machines ended the need for animal labor in the US.
Industrial farms use huge quantities of synthetic fertilizers, which, in the case of nitrogen, require significant fossil fuel inputs (primarily natural gas). A process called Haber-Bosch uses nitrogen from the atmosphere and fixes it with hydrogen derived primarily from natural gas to produce ammonia for fertilizer. About three to five percent of natural gas production is used in the Haber-Bosch process to produce nitrogen-based fertilizers. 1 In 2010, approximately 100 mega tons of nitrogen-based ammonia fertilizer were used worldwide (while less than three megatons were used in 1950). 2 Other non-renewable fertilizing agents (e.g., potassium and phosphorus) are mined, consuming energy in the process. Since plants do not absorb all of the fertilizer applied to the field, fertilizers can also flow from fields to waterways, contributing to algal blooms and potential dead zones. 3
Agriculture uses water intensively. Crop irrigation accounts for 29 percent of all water withdrawals in the US, and on livestock farms, a large supply is consumed by animals as drinking water and is also expended for other purposes, like waste management. 4 Agriculture competes with the energy sector for water needs. For example, water that is drawn out upstream for use in agricultural systems could lower the supply of a dam using water for hydropower electricity production. In addition, pumping, treating and moving large volumes of water from areas of abundance to drier agricultural areas of need all require a great deal of energy. About four percent of California’s electricity use is for agricultural purposes, with a good part of that to move water from the wetter northern part of the state to the arid, yet agriculturally productive regions in the south. 5 Additionally, two percent of the state’s electricity and five percent of the state’s natural gas consumption occurs in processing food. 6
Modern agriculture relies upon machinery that runs on gasoline and diesel fuel (e.g., tractors, sprayers, crop dusters, plows, trucks and combines), and equipment that uses electricity (e.g., lights, pumps and fans). In animal agriculture, much of the latter is required for use in indoor factory farm facilities, making pasture-based systems a more sustainable choice since they are less reliant on machinery.
Much of the food produced today is highly processed and heavily packaged, which further increases its energy footprint. In creating processed food, energy is used to grind, chop and mix products together and to cook, bake or otherwise handle the product. Manufacturing food packaging also requires energy; most food packaging is made from plastic, which is made out of petroleum. The amount of energy required for packaging varies greatly depending on the size, type and quantity of the materials. As a result of consolidation and centralization of production, foods are often transported long distances, requiring additional energy inputs.
Most meat, eggs and dairy products are now produced on factory farms, huge industrial livestock operations that raise thousands of animals in confined conditions without access to pasture. Since the animals are unable to graze, factory farms require tremendous quantities of feed produced by industrial crop farms using the energy-intensive processes described above. About half of the 90 million acres of land used to grow corn ends up as feed grain. And corn makes up about 95 percent of feed grain production. 7 Out of all acres of harvested cropland in the US, corn represents about 28 percent. 8 Factory farms are also potential sources of ground and surface water pollution, which may require municipalities and treatment facilities to expend additional energy and resources on water treatment.
Some factory farms use methane digesters to generate energy. These digesters capture methane released during the decomposition of the huge quantities of manure generated onsite, and then burn the gas to produce electricity. Although this reduces emissions of methane (a potent greenhouse gas), the technology: doesn’t eliminate solid waste; fails to address other environmental, human health, social and animal welfare problems created by factory farms and typically requires large subsidies to remain economically viable. Despite being touted as a “green” energy source, methane digesters ultimately serve to subsidize and further entrench the environmentally and socially destructive model of industrial livestock production. 9
Energy policy also affects agriculture. For instance, congressional mandates now require the production of billions of gallons of ethanol, which is primarily derived from corn. The US Environmental Protection Agency continues to hold corn derived ethanol rates high while allowing cellulosic ethanol production — which derives ethanol from grasses, wood or algae instead of crops — to stay at a low level. 10 Corn grown for ethanol takes land away from food production and, in states where corn is irrigated, uses a significant amount of water.
The modern food system depends on energy not only to produce food and to process it, but also to transport it from farms to markets. Food grown in conventional sustainable systems both depend on fossil fuels but to vastly different extents. Conventional distribution networks and food hubs can be optimized to deliver food in an efficient manner, but gains in energy efficiency may be offset by other sustainability concerns. So while conventional agriculture may appear to be more energy efficient due to economies of scale, externalities like fertilizer pollution, greenhouse gas emissions and animal welfare concerns are not included in that calculation. On the other hand, sustainable agriculture principles may not always be the most energy efficient in absolute terms, but they produce numerous other benefits such as increased soil health, pest control, erosion reduction and carbon storage. 11
Ultimately, energy intensity/efficiency is just one aspect of agriculture. Weeding and pest management, for example, may be more labor intensive in more sustainable practices, but could reduce the need for herbicides and insecticides. While sustainable agricultural practices require energy inputs just as conventional systems do, many opportunities for efficiency exist, and the benefits that accrue to other elements of the food system should not be overlooked.
The percentage of all US cropland used to grow corn
Food is fuel, but it’s not just powering humans and animals anymore, it’s also powering some of our transportation. Ethanol is derived from plants with the help of yeast to convert carbohydrates into alcohol. When blended with gasoline, the plant-based ethanol can be combusted in automobile engines to move vehicles. Biodiesel can be derived from plant oils or used as cooking grease.
In the US, due to the mandates set up in the country’s Renewable Fuel Standard, ethanol is the most prevalent biofuel. 12 The primary feedstock for ethanol produced in the US is corn. As much as 40 percent of the country’s harvested corn is used in ethanol production. 13
An increased market for corn ethanol may influence farmers to favor this plant over other crops, increasing corn acreage. The supply and demand in corn markets can result in volatile corn prices, which could allow fuel prices to spike if a particular year suffers from an extended drought. 14 Due to the dependence on corn-based feed, high corn prices could also drive up the price for chicken, beef, pork and other animal products that are produced in confined animal feeding operations (CAFOs). Oil and fertilizer prices, public perceptions about oil dependence and greenhouse gas emissions can also influence the debate over the effects of using a food crop for fuel. But in essence, ethanol mandates compound the many environmental effects of industrial-scale corn production. These include:
Some popular solutions for renewable energy actually complicate the relationship between our food and energy systems. Feedstocks that would otherwise be considered food, including corn, soy, sugar and palm, dominate the world markets for biofuels.
With the renewable fuel standard as law, ethanol is not going to go away anytime soon. And there is an argument to be made that since it is an effective octane booster, ethanol would still likely be the gasoline industry’s preferred choice even if the standard goes away. 21 So the environmental concerns with industrial corn production remain, but there is hope that breakthroughs in using enzymes to produce cellulosic ethanol from feedstocks like switchgrass, corn stover or even algae will help alleviate some of those concerns by converting marginal, low-value crops and crop residue into energy.
Farms are well suited to use their land for clean energy development. Wind developers can place wind farms in fields and ranchlands where farmers get paid to host the turbines and can continue to plant crops or graze animals around them. Already, over 90 percent of wind turbines are located on cropland and rangeland. 22 Some farmers own the turbines outright and can use the energy onsite to meet their electricity needs. Farmers that own wind turbines and/or solar panels can take advantage of the federal tax benefits and other state and local incentives for renewable energy to help them make the transition to cleaner energy.
Native grasses, switchgrass or other hardy plants can be planted and then harvested as biomass, which can be used as a fuel on the farm for heating. Future technologies may allow a farmer to convert the biomass into ethanol. Solar energy can also be harvested on the farm. Solar heat collectors that gather heat from the sun can dry harvest crops, heat homes, barns and other structures and provide hot water. Solar electric systems can provide onsite energy to power barns and other buildings, drive pumps and power electric fences. Farmers can also “farm the sun” by installing solar panels in large arrays on land unsuitable for crop or animal production and generate electricity that they can sell to electric grid operators. 23
To become less reliant on fossil-fuel-based farming practices, farmers can use fewer synthetic fertilizers by rotating crops that can fix nitrogen in the soil and then pasture animals on that land to take advantage of the natural fertilizer they provide. Cover crops and improved crop rotations can improve soil health, while helping the farmer to decentralize the monocrop. Reductions in monocropping and concentrated feed operations for animals will increase resilience and reduce the risk of system-wide losses. 24 More diverse farming operations also increase genetic diversity and smaller herd and flock sizes have a greater chance at containing outbreaks. Switching from feed to pasture will allow the farmer to reduce the fossil fuel resources required to produce and transport feed and the energy resources to raise and contain the animals.
Given the growing population’s food requirements, the world’s finite supply of fossil fuels and the adverse environmental impact of using this nonrenewable resource, the existing relationship between agriculture and energy must be rethought. Among the most obvious solutions would be to take advantage of energy efficiency upgrades in both food-production and distribution operations and thereby reduce dependence on fossil fuels. This can be accomplished by shifting away from fossil-fuel-intensive industrial agricultural techniques to less intensive methods (e.g., pasture-raised livestock, drip irrigation, non-synthetic fertilizers, no-till crop management, etc.), using more efficient machinery and equipment, reducing food processing and packaging, promoting decentralization of food production and improving the efficiency of food transportation.
Despite the challenges posed by the energy-intensive nature of agriculture, the prudent use of resources and judicious application of technology has the capacity to significantly improve the long-term sustainability of food production.