Our life under the Sun
by Adam Mandelman & Emma Schroeder
Banner photo: Theophilos, "Corn field," flickr.com, c. August 7, 2009, http://www.flickr.com/photos/theo_reth/3895474273/sizes/l/, accessed June 22, 2010.
Twenty-first century developments in biofuels technology, from corn-ethanol booms to the rise of new kinds of crops used exclusively for liquid fuels, may seduce us into imagining bioenergy as a new phenomenon. Yet it’s critical to remember that second-generation biofuels like ethanol and biodiesel are essentially no different from their first-generation counterparts, such as food and wood. Plants produce the energy stored in these fuels by converting the sunlight into sugars, making biofuels the oldest energy regime on the planet. This overview examines changing human relationships to bioenergy over time and recent developments in its geography, politics, and infrastructure.
Toward the end of the twentieth century, intensifying debates around climate change and renewable energies encouraged many of us to think about biofuels as a relatively new, highly technical energy source. We tended to conceptualize biofuels as corn ethanol, biodiesel, and combustible biomass used in power plants, like the one replacing the University of Wisconsin–Madison’s aging Charter Street coal plant. But biofuels, or more broadly “bioenergies,” have been powering life on earth since primitive bacteria first evolved the capacity for photosynthesis over 3000 million years ago.
Figure 1: The composition of US energy use since 1800 illustrates the long predominance of bioenergy in human livelihoods. Adapted from Cleveland, “Energy Transitions Past and Future.” 2
A few thousand million years later, and it was through using bioenergy (supplemented by wind and water power) that humans developed the first science, technology, and infrastructure. By burning first-generation biofuels in human and animal bellies and in fireplaces and furnaces, people planted and harvested fields, forged tools, built farms and towns, and erected waterwheels and sawmills.
So, biofuels aren’t just corn ethanol and combustible biomass for electricity generation. They’re also what we’ve used whenever we eat to power our muscles for work and play, whenever we’ve harnessed a yoke to a draft animal for transport or labor, and whenever we’ve burned wood, dung, charcoal, and even whale oil for cooking, warmth, or light. In fact, it’s courtesy of bioenergy that human beings were even able to lay the foundations for all subsequent energy regimes, including coal, oil, and nuclear. Bioenergy established the foundations of the transnationally connected, industrial world in which we live.1
Bioenergy originates with the sun. Plants use solar energy to convert water and carbon dioxide in the atmosphere into carbohydrates.
6 CO2 + 6 H2O + light energy = C6H12O6 + 6 O2
Autotrophic (self-nourishing) plants can synthesize new tissue (or biomass) from simple, inorganic inputs like water and carbon dioxide. By producing new biomass through this process of photosynthesis, many plants make solar energy available to organisms like animals and humans that are unable to synthesize tissues in this way. These heterotrophs make use of that plant-based energy by releasing it through respiration or, exclusively in the case of humans, by simply lighting biofuels on fire. Both processes involve breaking carbohydrates back down (i.e., oxidizing them) into their component parts of carbon dioxide, water, and energy.
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + energy
When released through respiration, that energy can be used to:
Ignoring the complexities of nutrition, the average energy cost for a wealthy-nation pregnancy would be covered simply by adding just four slices of toasted whole-wheat bread per day to the diet of a young, healthy, and active woman. Lactation, however, has a far higher energy cost, demanding up to 25% of a woman's daily intake.
Even more incredibly, women in poorer regions have given birth to healthy children on diets as much as 50% short of what would be expected.
And of course, all the energy that has dispersed up the food “chain” (really more of a “web”), from plants into herbivores, remains available to omnivores and carnivores further out in the “web.” Decayers, like bacteria and fungi, break the tissues of dead biomass back down into the simple, inorganic compounds used by plants for photosynthesis, completing the bioenergy cycle.
Just as energy moves through food webs, so too does carbon. Burning plant biomass releases carbon into the soil and atmosphere, carbon that will then be reincorporated into other plants as they synthesize new tissue. It’s important to remember that biofuels are only carbon neutral if the carbon released through burning biomass for energy is offset by an equal amount of carbon sequestered in new vegetation.4
The vast majority of human existence has been spent foraging, which is to say, relying on our own muscle power as fueled by bioenergy. Foraging for seeds, nuts, fruits, and tubers could have a reasonably profitable energy return on investment, yielding anywhere from five to thirty times the energy expended in gathering them. Depending on geography, however, these resources could be extremely seasonal.5
It was the human body’s uniquely successful solution to an energy problem that enabled hunters to run down game.
Humans, through highly efficient sweating, can dissipate excess heat produced by working muscles much more rapidly than animals.
Although animal bodies may be faster early in the chase, slower cooling systems can make them succumb quickly to exhaustion and, consequently, their human hunters.
So, while hunting tended to yield low (and sometimes negative) energy returns—large amounts of energy were spent to procure comparatively little biomass—wild game supplemented protein and fat-deficient diets and helped smooth out some of the seasonal irregularities in plant biomass availability. Of course, there have also been important exceptions to hunting’s low energy returns, such as the massive biomass of wooly mammoths, the wholesale slaughter of bison herds through corralling, and the enormous quantities of salmon available during spawning season.6
It follows that one way of understanding how bioenergy production and consumption has changed over time is through examining major dietary transitions around the world. Rising consumption of carbohydrate staples like rice, cereals, and potatoes, for instance, marked the development of sedentary agriculture. Instead of obtaining all of their calories from hunting and foraging, many cultures began using increasingly sophisticated tools to harness animal labor and maximize human muscle power.
Well, sort of. According to energy historian Vaclav Smil, ancient master architects controlled (at best) the combined human muscle equivalent of about 10,000-100,000 watts. In more concrete terms, that’s the equivalent of a single engine powering just one of today’s earthmovers.
Some of these advances included metal hand tools, plows, shoes for draft animals, and improved harnesses, all of which served to maximize muscle efficiencies. Levers, inclined planes, and wheels were combined in various ways to make screws, pulleys, winches, tread-wheels, gears, and other devices that not only resulted in energy efficiencies, but also multiplied the forces a human or draft animal could exert. Such developments allowed not only for more intensive agriculture, but also for the construction of massive edifices like the pyramids through the use of bioenergy alone.7 With the right mechanical inputs, sedentary cultivation could yield a much higher energy return on investment than hunting and gathering.
More recently, food transitions in industrialized nations, particularly after World War II, illustrated still greater chemical and mechanical inputs in the production of bioenergy (i.e., agriculture). Declines of up to two-thirds in the consumption of starchy staples like potatoes, bread, and rice were matched by similar moves away from high-protein legumes like beans, peas, and soy. Bioenergy for human muscles in affluent countries, then, increasingly came from meat, fish, eggs, and animal and vegetable fats, rising from just 10% of many diets to over 30%.8
Early agriculture mostly raised animals for their labor rather than for their flesh. Up to 90% of the grains, tubers, and legumes fed to animals could be consumed by their metabolisms, producing comparatively little meat. Raising animals on pasture of course avoided this problem, but also left less land available for cultivation.9
Industrialization of the food system, however—via inputs ranging from petroleum and electricity-powered mechanization to petroleum-based fertilizers and pesticides—produced such seemingly high yields that meat production no longer seemed like a dangerous waste of calories (although the actual energy costs of those yields are rarely priced into the system). Similarly, the highly milled flours and processed fats consumed in wealthy countries instead of whole grains reflect the industrialization of bioenergy production.
Mechanical inputs also transformed the way humans and animals labored over transportation. Better wheel and wagon designs, greased axles, and improved road surfaces helped maximize energy efficiencies. Canals, meanwhile, allowed human and animal muscle to pull loads without exerting nearly as much effort as land-based transportation, thanks to the reduced friction offered by water surfaces. The relatively late arrival of safe and user-friendly bicycles in the 1890s applied the mechanical advantages that had long been used in pulleys and gearwheels to human-powered transportation.10
All of this has so far only concerned muscle power, but somewhere between 1.5 million and 250,000 years ago, we expanded our bioenergy repertoire to also include the use of fire for lighting, heating, and cooking.11 Major fuels have included wood, charcoal (mostly for forging metals), and crop residues. The large majority of the world still relies on these fuels as primary energy sources. In fact, even in Wisconsin over 65% of renewable energy used in 2007 came from wood.12 And while these biofuels were all used for light or heat, none of them were used to do mechanical work until the invention of steam engines in the 18th century.
Advances in lighting appeared around 40,000 years ago in Europe with early lamps burning animal fat. Beef tallow and beeswax candles only appeared in the Middle East around 800 B.C.E. Whale oil, which burned with marginally more efficiency than these earlier fuels, reached its peak use in the mid-nineteenth century. Soon after, competition from petroleum-based fuels put an end to the hard, dangerous life of whaling for lamp oil.13
Contemporary, second-generation biofuels (e.g., ethanol from fermented plant sugars and biodiesel produced from vegetable fats) are also not as new as some might think. Burning wood to power nineteenth-century steamboats isn’t much different from burning biomass in power plants to generate electricity: the former produces kinetic energy; the latter uses the same kinetic energy to turn dynamos producing electrical energy. Likewise, liquid biofuels have a history reaching at least as far back as 1908, when Henry Ford designed his Model T automobile to use ethanol.14 Political pressure to produce new biofuels is also hardly new, as President Carter called for development of “America's own alternative sources of fuel—from coal, from oil shale, from plant products for gasohol, from unconventional gas, from the sun.”15
Figure 2: The global expanse of potential bioenergy fuel sources is apparent in this 2008 satellite photo of global vegetation and chlorophyll concentration. Darker green shading indicates more vegetative cover (potential biofuel stocks) while lighter areas of the oceans show more chlorophyll and therefore more oceanic autotrophic activity (primarily algae). Image courtesy of NASA’s Earth Observatory.18
Plants capture the sun’s energy everywhere, making bioenergy a global resource. However, we cannot use all of the energy stored by plants. Available technologies only allow us to use seeds and grains, which are readily fermented into alcohols; yet these also provide the most food energy to humans.16 Because of growing concerns about the impact second-generation biofuels may have on food production, researchers are looking for ways to make use of cellulosic feedstocks such as switch grass, a perennial we do not eat and that thrives on land we are not able to farm. Yet at the beginning of the twenty-first century, we are limited to biofuels from crops that also provide us with food. Croplands covered about 1800 million hectares of the Earth’s surface in 2008, with fuel crop cultivation covering 36 million hectares, or 89 million acres—equal to the number of acres of corn grown in the United States in 2007! By 2030, 118 to 508 million hectares (or 8 to 36% current cropland) would be required to provide just 10% of global transportation fuel.17
In the United States, energy policy has primarily encouraged ethanol production from corn, landfill methane capture, waste-to-energy incinerators, manure digesters, and co-burning of biomass with coal. A total of 86,248,542 acres of corn was harvested for grain in the United States in 2007, most of it in the Midwest. However, only 10% of this corn went directly to American stomachs, while 19% of the harvest was processed into ethanol. The rest was exported, fed to animals, kept for seed, or used in industrial processes. 19
Wisconsin’s forests, corn fields, and dairy cows provide extensive bioenergy feedstocks. Where there are no forests, there are farms–a landscape ripe for bioenergy harvesting.
Figure 3: Acres of corn harvested in the U.S. in 2007. Image courtesy of USDA.20
Figure 4: Bushels of corn harvested for grain in Wisconsin by county in 2007. Image courtesy of University of Wisconsin – Extension Center for Community and Economic Development.21
Figure 5: Acres of forest land by Wisconsin county. Image courtesy of University of Wisconsin – Extension Center for Community and Economic Development.22
Muscles can’t power muscle cars, so while first-generation biofuels (wood, dung, food) are the ones humans still rely on the most, governments are subsidizing the development of second-generation biofuels with higher energy densities, including: ethanol, biodiesel, and biogas.
We haven’t changed the kinds of bioenergy feedstocks we use, just how we access the energy they store. Compare the process of harnessing first-generation biofuels:
compost → worms and bacteria → soil and photosynthesis → new plants
wood → wood stove → heat
pasture → ruminant stomach → dung → fire → heat
grains → stomach → brawn and brain
With that of creating and using second-generation biofuels:
corn → biorefinery fermentation and distillation → ethanol → muscle cars
wood and natural gas → co-burning power plant → electricity and heat
pasture → ruminant stomach → dung → digester → methane, humus, and water
By the beginning of the twenty-first century, there were three second-generation technologies for extracting renewable energy from biofuels:23
Badger State Ethanol in Monroe, WI uses a dry-mill fermentation process. Corn arrives by train and truck around three times per week, after which it is screened for rocks and corn cobs and then ground into a fine powder. Water, heat, and enzymes then convert the cornmeal starches into a sugary slurry. Yeasts added to the slurry will then ferment the mixture for 48-50 hours. The resulting corn mash is then distilled and passed through molecular sieves to yield 200 proof ethanol. “Distillers dried grains,” a byproduct rich in protein, starch, and nutrients, are sold as cattle feed.24 Badger State Ethanol also pipes raw carbon dioxide gas to a nearby facility owned by liquid carbon dioxide supplier, EPCO. Liquid CO2 has food, beverage, and industrial applications.25
Wet milling is an alternative process that separates corn into starches, fats, proteins, and fiber before further processing. Wet milling produces food additives like high-fructose corn syrup in addition to ethanol.26
Cellulosic ethanol production distills ethanol from the fermented sugars of whole plants rather than just grains. Plant matter is treated through a chemical process called hydrolysis that makes sugars trapped in woodier materials available for fermentation. Cellulosic ethanol is thought to have a higher energy return on investment than corn ethanol.27
Distribution networks on both the input (feedstocks) and output (energy) side complicate power generation and liquid fuel production from biomass.
Because even the most efficient crops and plants under the best conditions convert only about 2% of solar energy into carbohydrates (the global terrestrial average is only 0.33%), biofuels are fundamentally low-density energy sources, which require extensive acreages for adequate production.28 Pre-industrial cities typically needed nearby wooded areas between 50 and 150 times the size of the city itself in order to maintain a steady supply of biofuel.29 The low-energy density of biomass persists as a logistical problem for large-scale power and liquid biofuel production today.
For example, the University of Wisconsin–Madison’s Charter Street Heating Plant will soon be overhauled to burn biomass and natural gas, instead of coal, for heating, cooling, and electricity generation.30 The much lower energy density of biomass compared with coal (grasses and green wood have as little as one-sixth the energy density of some coals) means that the plant will require much higher quantities of fuel in order to run. Because storage is limited, the plant expects biomass deliveries of up to 32 rail cars per day, five or six days per week. This is about triple the amount of rail traffic compared with when the plant was burning its largest quantities of coal (about 125,000 tons). These delivery demands require both a new storage site and rail delivery line to avoid increasing congestion.31
Methane captured at landfills, electricity generated at waste-burning facilities, and biogas produced in manure digesters present other bioenergy distribution problems related to inputs. These biomass facilities concentrate trash and manure in one place, making use of fairly unpopular materials. As with any energy production for the grid, waste-to-energy plants and manure digesters demand a constant feedstock supply. Building the infrastructure required for this type of bioenergy requires host communities to frequently accept undesirable waste from elsewhere whenever their own supplies run short.
While Madison’s Charter Street Heating Plant directly heats and cools about 300 buildings in the immediate area, not all second-generation bioenergy is so easily distributed and consumed.32 Electricity distribution takes place through the complex infrastructures, economies, and regulations of the grid.
Liquid and gas fuels require transportation from processing plants like Badger State Ethanol to gasoline blenders, fuel distributors, and, ultimately, consumers at the pump. Distributing ethanol is even more challenging because the fuel can corrode some storage tanks and pipelines.33
Bioenergy production in the United States—including both liquid fuels for transportation and combustible biomass for power generation—is most obviously and explicitly regulated by environmental quality legislation like the Clean Air Act.34 Less obvious, though, are the ways bioenergy production gets passively regulated through economic incentives. So, in addition to the US Department of Agriculture (USDA), the Department of Energy (DOE), and the Environmental Protection Agency (EPA), agencies that seemingly have nothing to do with energy—such as the Internal Revenue Service (IRS) and Customs and Border Protection (CBP)—actually play important roles in overseeing the resource (see table, below).
There were also a handful of major bills passed in the first decade of the twenty-first century that have had important and direct consequences for bioenergy development in the United States:
The Energy Policy Act of 2005 (EPAct 2005) created tax credits for biofuels producers, loans for renewable energies, and grants for cellulosic ethanol projects. Most critically, it introduced the Renewable Fuel Standard, which mandated that gasoline sold in the United States would contain at least 7.5 billion gallons of renewable fuels by 2012. The Renewable Fuel Standard would be made more robust with the Energy Independence and Security Act of 2007.35
The Energy Independence and Security Act of 2007 (EISA) established a more aggressive Renewable Fuel Standard that required annual increases in the amount of renewable fuels to be blended with conventional transportation fuels. The new standard mandated an increase from 9 billion gallons in 2008 to 36 billion gallons by 2022.36 To put this in context, the US consumed around 209 billion gallons of petroleum for transportation in 2008, more than 23 times the amount of blended renewables consumed that year.37
The Food, Conservation, and Energy Act of 2008 (The 2008 Farm Bill) expanded on renewable energy policy first enacted by the 2002 Farm Bill. Like the 2002 Farm Bill, it contained a section dedicated to energy policy called “Title IX.” The 2008 Farm Bill paid special attention to biofuels, including:
Developing and regulating bioenergy resources in the United States is a major challenge both domestically and internationally. Legislation that encourages biofuel production through agricultural subsidies, for example, can risk anti-protectionism sanctions from the World Trade Organization.39 Bioenergy production can also have unpredictable effects on both domestic and global land use. Particular feedstocks may, in boom times, send market signals encouraging farmers to dramatically change agricultural practices around the world, as in the case of corn in the United States and soybeans in Brazil. Those land-use changes can in turn affect food and other commodity prices, with potentially serious social consequences. Finally, research revealing other unintended consequences of biofuels—such as the large quantities of energy required to produce corn ethanol and the carbon dioxide emitted in that process—inevitably adds to the regulatory complexity around the resource.40
Grants and loans for renewable energy projects and value-added agricultural activities, including liquid biofuels production.
Feedstock reimbursements for expanded ethanol and biodiesel production.
Grants and loans for renewable energy projects and value-added agricultural activities, including biomass-based power generation.
Grants and loans supporting research and development.
Loans for cellulosic ethanol production facilities.
Per-gallon production incentives for cellulosic biofuel producers.
Grants and loans supporting research and development.
Loans for reducing greenhouse gases, which could include biomass-based power facilities.
The Renewable Fuel Standard41 requires that US transportation fuels contain a minimum volume of fuels from renewable sources.
Tax credits for:
Ethanol and biodiesel producers.
Gasoline suppliers who blend ethanol with gasoline.
Cellulosic ethanol production plants.
Import duties on ethanol.
The diversity of bioenergy feedstocks makes evaluating their impact on surrounding environments, CO2 emissions, and food security, difficult to decipher. Life-cycle analyses are methodologically inconsistent, with each review making different assumptions.42 Studies vary in:
Biofuels are an extensive resource, as feedstock production requires more land area than traditional energy sources. Because of this, their effect on land cover change at large scales must be weighed against any possible reduction in greenhouse gas emissions.
If more land is farmed for biofuel production, it is likely fertilizer use will also increase. Not all of the synthetic nutrients contained in fertilizer remain on fields; the release of excess nutrients into water bodies may cause increased algal growth, thereby reducing oxygen available to heterotrophs, ultimately leading to their deaths. This process is known as eutrophication, and can be expected to increase as more land is converted to crops.44
Air pollution, including nitrogen dioxide and sulfur dioxide, also may increase with intensified burning.45 Often producers reduce feedstock processing costs by placing refineries in agricultural areas, resulting in an industrialization of rural land. Biofuels may reduce greenhouse gas emissions, but it depends on what type of land is used to grow them. When comparatively natural lands are converted to cropland, biofuels may actually increase greenhouse gas emissions because cultivation eliminates what was previously a site for carbon storage.46
In producing ethanol, we may actually get less energy out than we put in (the energy return on investment may be below 100%). Studies show a range of energy returns on investment from only retrieving 77% of the energy we expended making a fuel, to a net gain of 42%; inconsistencies that arise due differences in where researchers draw the boundaries of energy systems.47 However, using biomass wastes may be positive energetically. Proponents argue that corn stover (everything but the kernels), landfill gas, and wood scraps are waste products which could be utilized for energy. But wood left on the forest floor or cornhusks are not ‘waste’ to soil decomposers, forest fungi, or to farmers needing to maintain soil organic matter.48
Food or fuel? Even without considering biofuel production, the causes of food insecurity are variable and difficult to untangle. Food security depends not only on sufficient arable land, but also on social structures which facilitate people’s access to food. With global population growth we will need to produce more food, and cultivation of bioenergy feedstocks may compete for limited agricultural land. 49 One measure of access is price, and whether bioenergy production will lead to increased prices depends upon multiple factors: affect of the new, corn-for-fuel market; how biofuel markets change other commodity prices; cellulosic bioenergy technologies; and national policies regulating biofuel production.50
Energy security will increase. As bioenergy is something that can be produced anywhere, increasing our supply of it means less reliance on imported fuels.51 However, the low energy-density of biofuels means that they cannot replace fossil fuels completely. Biorefineries, transportation, and technological development create jobs, especially in rural areas near biomass sources (woods, farmlands, dairy farms).
Figure 6: Advertisement arguing that biofuels will increase Wisconsin’s energy independence and boost its farming economy. The Cap Times, March 3-9, 2010, Back Page.
The Didion Ethanol plant in Cambria, Wisconsin began producing ethanol in April of 2008. Since the plant’s opening, community members have complained about the odors, noise, air and water pollution from the plant, as well as falling home values. The plant has violated both air and water quality permits issued by the state’s Department of Natural Resources (DNR). While Didion is working towards mitigating its environmental impacts, it is also “applying for new DNR permits whose parameters, while still within state environmental regulations, more realistically reflect the company’s operations.” This would mean that the plant would be allowed to discharge more waste into the air and water, rather than be forced to reduce effluents.52 The story of Didion’s noncompliance reflects the ethanol industry in Wisconsin, as six of Wisconsin’s nine ethanol plants have been charged by the DNR for permit violations.53 Despite the environmental violations, the Didion plant is slated to expand operations with funding from the Department of Energy’s program for industrial efficiency. The $11 million in improvements (half coming from the federal government) will include a new corn extraction process, increased fermentation capacity, as well as storage and evaporation infrastructure. The expanded plant will provide 85 new jobs—10 permanent and 75 construction positions. Farmers backed the expansion, claiming the increased capacity will ensure that a market exists for their corn.54
Jobs are not only created for farmers, but for the University of Wisconsin as well. A Department of Energy grant of $125 million over 5 years established the Department of Energy’s Great Lakes Bioenergy Research Center to develop cellulosic bioenergy technologies. The mission of the Great Lakes Bioenergy Research Center is part of the larger Wisconsin Bioenergy Initiative, which “promote[s regional economic growth in the context of good environmental stewardship.”55
Figure 7: Grain elevators in Edon, Ohio. The tallest cylinder is the “leg.” Note the pipes (right of the leg) and the conveyor (lying horizontally above the concrete cylinders) distributing the lifted and sorted grain. Image courtesy of Mr. Harman and is licensed under Creative Commons Attribution-Share Alike 3.0.
Bioenergy is all around us. Every living thing is either synthesizing biomass from the sun’s energy or consuming other organisms in order to fuel their bodies. That said, there are a few specific elements of our bioenergy infrastructure that are worth noticing in the landscape: gardens, farms, and renewable energy production facilities.
Take a walk through your neighborhood and you might see the small-scale bioenergy production facility we call a vegetable garden. Whether in neat rows or haphazard mounds, food gardens embody the labor necessary to clear land, condition soil, and guard against a variety of intruders (from fungus to insect, mammal to bird). The result: plants containing carbohydrate, protein, and oil concentrations far higher than most wild flora. Food gardens are some of our most humble and common, though perhaps least thought about, forms of human-engineered bioenergy in the landscape.56
Making a much more noticeable mark on the land are modern farms, particularly industrialized grain and feedlot operations. Since biofuel crop supplies—whether for human consumption, animal feed, or liquid biofuels production—are seasonally variable while demand remains constant, they require conspicuous storage facilities. Grain elevators (fig. 7) are some of the most recognizable of these facilities and typically consist of a tall, central structure called a “leg,” which lifts and sorts the grain into a series of massive concrete or steel cylinders. In times of extreme surplus, you might also notice massive piles of grain stored under plastic sheeting weighed down by discarded tires.
Figure 8: Harvestore silos, southeastern Lee County, Illinois. Image courtesy of Mark Ellis and is licensed under Creative Commons Attribution-Noncommercial-Share Alike 2.0 Generic.
Figure 9: Eight-foot diameter bag silo just after filling and sealing, Chippewa County, Wisconsin. Image courtesy of D. Mahalko and is licensed under Creative Commons Attribution 3.0 Unported.
Silos serve the double purpose of both storing and fermenting hay or corn bioenergy to produce an animal feed called silage. Although they look somewhat similar to grain elevators in height and shape, you won’t find a “leg” attached to a silo. Instead, a device chops the biofuels into fine pieces and blows them up into the tower. Newer Harvestore steel (as opposed to concrete) silos (fig. 8) are marked by a dark-blue ceramic coating that prevents the structure from being corroded by the acidic silage. And if you ever happen to see a large (8 to 12 feet across), long plastic tube lying on the ground at a farm, well, that’s a silo too (fig. 9)! The plastic tubing maintains the high-pressure, oxygen-free fermentation environment of the tower silo, but avoids its significant capital costs and technical challenges.57
Figure 10: “Feed” corn (top) and “sweet” corn (bottom). Image courtesy of www.ilcorn.org.
When vegetable biofuels aren’t in storage, it’s also helpful to be able to recognize them in their growing form. While telling soy from corn isn’t much of a challenge, distinguishing “sweet” corn bound for the supermarket from “feed” corn to be transformed into beef, ethanol, or commercial food additives is tricky. Luckily, there are a few key identifiers: sweet corn plants are usually two feet shorter than their field corn cousins and have smaller stalks as well as smaller, and perhaps fewer, ears of corn per plant. Moreover, field corn kernels develop a characteristic dent and tend to be darker and more orange than sweet corn varieties.58
Figure 11: Ethanol plant in West Burlington, Iowa. Note the fermentation tanks on the far left. Image courtesy of USDA.
Identifying biofuels-based renewable energy facilities in the landscape can be similarly challenging. Biorefineries like ethanol plants (fig. 11) often look just like another set of grain elevators, as pictured in the right side of the photograph. The fermentation tanks and on the left side of the image, however, are a dead giveaway. Likewise, solid biomass combustion plants can be hard to recognize because they can look just like conventional power plants. Biomass plants that burn waste, however, can usually be identified by an attached transfer station or waste disposal facility. Paper mills—easily recognizable by their pungent odor—are usually a clear sign of industrial bioenergy in the landscape because they burn bark and other waste products from the paper-making process to generate steam-powered electricity.59
Finally, since wood fuel is one of our most commonly used renewable energy sources, knowing how to recognize it is an important, if deceptively easy, exercise. Despite the technological overtones of most combustible biomass energy production, over 65% of Wisconsin’s renewable energy use in 2007 came from wood, with most of it being burned in homes, schools, and businesses for heat. While technically any woody biomass in the landscape is potentially wood fuel, there are legal and economic obstructions to gathering just any fuel wood you come across. Moreover, because timber is currently so much more valuable than firewood, trees are almost never grown specifically for energy purposes. Rather, tree farms will contract out to biomass harvesters who transform slash—waste logs, stumps, and other logging residue—into chips, pellets, and cordwood. If you find a tree farm, you’ve also found a firewood farm.60
Hayes, Brian. Infrastructure: A Field Guide to the Industrial Landscape. NY: W. W. Norton & Co., 2005.
Milbrandt, A. A Geographic Perspective on the Current Biomass Resource Availability in the United States. Goldern, CO: National Renewable Energy Laboratory, December 2005.
Muller, Mark, Tammy Yelden, and Heather Schoonover. “Food versus Fuel in the United States: Can Both Win in the Era of Ethanol?” Institute for Agriculture and Trade Policy, 2007.
Nye, David. Consuming Power: A Social History of American Energies. Cambridge, MA MIT Press, 1998.
Petrou, E.C. and C.P. Pappis. “Biofuels: A Survey of Pros and Cons.” Energy and Fuels 23 (2009): 1055-1066.
Smil, Vaclav. Energy: A Beginner’s Guide. Oxford: Oneworld Publications, 2006.
Smil, Vaclav. Energy in World History. Boulder, CO: Westview Press, Inc., 1994.
United Nations Environment Program. Towards Sustainable Production and Use of Resources: Assessing Biofuels. 2009. http://www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf (Accessed April 12, 2010)
U.S. Environmental Protection Agency and National Renewable Energy Laboratory. State Bioenergy Primer. September 15, 2009.
Autotroph literally means “self nourishing” and refers to organisms that can synthesize biomass from simple, inorganic inputs like water and carbon dioxide. All photosynthetic plants are autotrophs.
Biodiesel is a second-generation biofuel produced from vegetable fats and oils.
Biomass is both a first and second-generation biofuel and refers simply to plant or animal tissues.
Biorefineries process biomass into second-generation biofuels. An ethanol plant is a biorefinery.
Carbon neutral refers to processes that do not result in a net gain in carbon dioxide in the atmosphere. Preventing further increases atmospheric carbon dioxide is one way to mitigate climate change.
Cellulosic Ethanol is a second-generation biofuel distilled from fermented sugars in whole plants, rather than grains. Though more technically challenging, it is thought to have a higher energy return on investment and lower carbon footprint than grain-based ethanol.
Cellulosic Feedstocks are the biodfuels derived from insoluble carbohydrates plants use for structure.
Corn Stover is all parts of corn except the kernels, usually used for cattle feed. It is one type of cellulosic feedstock.
Distiller’s Dried Grains are a byproduct of dry-mill ethanol production. Rich in protein, starch, and nutrients, distiller’s dried grains are sold as cattle feed.
Dry-Mill Fermentation grinds and ferments corn for ethanol production.
Energy Return on Investment (EROI or ERI) is the ratio of energy delivered to the energy used in producing it. Ratios of less than 1 indicate that more energy will be expended in producing a fuel or energy source than that fuel or energy source will yield. Ratios of greater than one indicate that more energy will be yielded than expended.
Ethanol is a second-generation biofuel distilled from fermented sugars in grains like corn.
Eutrophication refers to a process in which the release of excess nutrients into water bodies causes increased algal growth, thereby reducing oxygen available to heterotrophs, ultimately leading to their deaths.
Feed (or Field) Corn is a variety of maize used for animal feed or ethanol production.
Feedstocks are raw materials required for fuel and energy production.
First-Generation Biofuels include human and animal feed, wood, dung, whale oil, and so on. In short, all fuels produced directly through photosynthesis or indirectly through an animal’s consumption of photosynthetic biomass (plants).
Grain Elevators lift, sort, and store grains like corn.
Greenhouse gases are atmospheric molecules that trap heat near the Earth’s surface, leading to climate change.
Heterotrophs rely on other organisms for food energy and other inputs to synthesize biomass. All animals (except the sea slug, Elysia chlorotica) are heterotrophs.
Leg: the tallest structure attached to a grain elevator. It lifts and sorts the grain for storage.
Life-Cycle Analysis is a research method in which researchers track all inputs and outputs of a production process in order to better understand associated environmental costs.
Renewable Fuel Standard (RFS): a piece of legislation introduced in the Energy Policy Act of 2005. It mandates gasoline sold in the United States contain a specific percentage of renewable liquid fuel.
Second-Generation Biofuels are modern fuels produced through chemical, biochemical, or thermochemical processes that condense and extract the energy stored in a biomass feedstock.
Silage is an acidic, fermented-grain animal feed.
Silos store and ferment grains like corn to produce silage.
Slash is the debris leftover after logging and includes waste logs, branches, and stumps.
Sweet Corn is a variety of maize for human consumption.
Title IX is a section of both the 2002 and 2008 Farm Bils that was dedicated to energy policy.
Tree Farms grow trees for commercial use, usually lumber and paper. Waste products from logging operations are sold to firewood suppliers.
Vegetable Garden a humble and commonplace bioenergy production facility.
Wet-Mill Fermentation separates corn into starches, fats, proteins, and fiber before further processing. Wet milling produces a variety of products in addition to ethanol, including high-fructose corn syrup.
1 For more on the notion that bioenergy established the foundations for all subsequent energy regimes, see David Nye, Consuming Power: A Social History of American Energies Cambridge, MA: MIT Press, 1998), chapter 1.
2 Cutler J. Cleveland, “Energy Transitions Past and Future,” in The Encyclopedia of Earth, ed. Cutler J. Cleveland (Washington, DC: Environmental Information Coalition, National Council for Science and the Environment, 2007), http://www.eoearth.org/article/Energy_transitions_past_and_future (accessed April 13, 2010).
3 Vaclav Smil, Energies: An Illustrated Guide to the Biosphere and Civilization (Cambridge, MA: MIT Press, 1999), 83-5.
4 E.C. Petrou and C.P. Pappis, “Biofuels: A survey of pros and cons,” Energy and Fuels 23 (2009): 1062.
5 Vaclav Smil, Energy: A Beginner’s Guide (Oxford: Oneworld Publications, 2006), 63.
6 Smil, Energy, 64-6. For more information on human heat dissipation and hunting, see: Vaclav Smil, Energy in World History (Boulder, CO: Westview Press, Inc., 1994), 24-5.
7 Smil, Energy in World History, 92-102, 155, 227.
8 Smil, Energy, 129-33.
9 Smil, Energy, 67; Smil, Energy in World History provides some interesting calculations on the average cropland costs of keeping horses in the early twentieth-century United States, 91.
10 Smil, Energy; 76-7; Smil, Energy in World History, 134.
11 Smil cites the oldest figure in Energy, 54 and the most recent in Energy in World History, 17.
12 Jim Doyle and Judy Ziewacz, 2008 Wisconsin Energy Statistics: Highlights (Madison, WI: Office of Energy Independence, 2009), 3, 20.
13 Smil, Energy in World History, 124.
14 U.S. Environmental Protection Agency, Biomass Conversion: Emerging Technologies, Feedstocks, and Products (Washington, DC: U.S. Environmental Protection Agency, 2007), 1. Also available at http://www.epa.gov/sustainability/pdfs/Biomass%20Conversion.pdf (accessed April 11, 2010).
15 Jimmy Carter, “Crisis of Confidence,” Televised speech, July 15, 1979. http://www.pbs.org/wgbh/amex/carter/filmmore/ps_crisis.html (accessed April 12, 2010).
16 United Nations Environment Program, Towards sustainable production and use of resources: Assessing biofuels, 2009. http://www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf (accessed April 12, 2010); U.S. Environmental Protection Agency, Renewable Fuel Standard Program: (RFS2) Regulatory Impact Analysis, EPA-420-R-10-006, February 2010.
17 United Nations Environment Program,18.
18 National Aeronautics and Space Administration’s Earth Observatory. Global Biosphere, 2008 image. http://earthobservatory.nasa.gov/Features/WorldOfChange/biosphere.php (accessed April 14, 2010)
19 Ephraim Leibtag, “Corn prices near record high, but what about food costs?” Amber Waves, February 2008. http://www.ers.usda.gov/AmberWaves/February08/Features/CornPrices.htm (accessed March 26, 2010)
20 United States Department of Agriculture, National Agriculture Statistics Service. 2007 Census of Agriculture. http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Ag_Atlas_Maps/Crops_and_Plants/Field_Crops_Harvested/07-M163.asp (accessed March 19, 2010)
21 University of Wisconsin Extension. Wisconsin Bioenergy Sites and Sources: Site and Source Concepts - Agricultural Resources. http://www.uwex.edu/ces/cced/bioeconomy/crops.cfm (accessed March 18, 2010)
22 University of Wisconsin Extension. Wisconsin Bioenergy Sites and Sources: Site and Source Concepts – Forest Resources.
http://www.uwex.edu/ces/cced/bioeconomy/woodybio.cfm (accessed March 18, 2010)
23 For more on general production processes see: U.S. Environmental Protection Agency, Biomass Conversion, 9, 12-13; Massoud Kayhanian, George Tchobanoglous, and Robert C. Brown, “Biomass Conversion Processes for Energy Recovery,” in Handbook of Energy Efficiency and Renewable Energy, ed. Frank Kreith and D. Yogi Goswami (Boca Raton, FL: CRC Press, 2007).
24 Badger State Ethanol, “Ethanol Production Process,” Badger State Ethanol, http://www.badgerstateethanol.com/industry_process.htm (accessed April 11, 2010); Badger State Ethanol “Dry Mill Process,” Badger State Ethanol, http://www.badgerstateethanol.com/downloads/drymillprocess.pdf (accessed April 11, 2010); Badger State Ethanol, “Distillers Dried Grains with Solubles,” Badger State Ethanol, http://www.badgerstateethanol.com/downloads/drydistillers2009.pdf (accessed April 11, 2010).
25 Badger State Ethanol, “Ethanol Production Process”; Badger State Ethanol, “CO2,” Badger State Ethanol, http://www.badgerstateethanol.com/products_co2.htm (accessed April 11, 2010); EPCO, “Home,” EPCO, http://www.epcoco2.com/index.html (accessed April 11, 2010).
26 Kreith and Goswami, “Biomass Conversion Processes,” 55-6.
27 U.S. Environmental Protection Agency, Biomass Conversion, 2, 5; Kreith and Goswami, “Biomass Conversion Processes,” 65.
28 Smil, Energy, 42.
29 Smil, Energy, 73.
30 Carla Vigue, “Governon Doyle Announces Charter Street to Burn Biomass,” Wisconsin Office of the Governor Media Room, http://www.wisgov.state.wi.us/journal_media_detail.asp?locid=19&prid=3939 (accessed April 11, 2010).
31 For comparing energy densities, see: Smil, Energy in World History, 12. Expected biomass delivery schedule available at: Wisconsin Bioenergy Initiative, “Charter Street Biomass Heating Plant,” Wisconsin Bioenergy Initiative, http://www.wbi.wisc.edu/charter-street-biomass-heating-plant/ (accessed April 11, 2010). Coal and biomass delivery information courtesy of John P. Harrod, Jr., Physical Plant director at UW-Madison, personal communication, April 12, 2010.
32 Wisconin Bioenergy Initiative, Charter Street Biomass Heating Plant.”
33 U.S. Environmental Protection Agency, Biomass Conversion, 9.
34 For comments on environmental regulations and bioenergy production, see: Thomas F. McGowan, ed., Biomass and Alternate Fuel Systems: An Engineering and Economic Guide (Hoboken, NJ: John Wiley & Sons, 2009).
35 A brief overview of EPAct 2005 can be found at: U.S. Department of Energy Office of Energy Efficiency and Renewable Energy, “Federal Biomass Policy,” U.S. Department of Energy, http://www1.eere.energy.gov/biomass/federal_biomass.html (accessed April 11, 2010).
36 Office of Energy Efficiency and Renewable Energy, “Federal Biomass Policy.” More information on the new Renewable Fuel Standard is also available at: U.S. Environmental Protection Agency, “ Renewable Fuel Standard,” U.S. Environmental Protection Agency, http://www.epa.gov/otaq/fuels/renewablefuels/index.htm (accessed April 11, 2010).
37 Based on an estimate of 13,651,000 barrels/day converted to gallons: U.S. Energy Information Administration, “Table 5.13c Estimated Petroleum Consumption: Transportation Sector, Selected Years, 1949-2008”, U.S. Energy Information Administration, http://www.eia.doe.gov/emeu/aer/pdf/pages/sec5_32.pdf (accessed April 11, 2010).
38 Tom Capehart, “Renewable Energy Policy in the 2008 Farm Bill,” Congressional Research Service RL 34130, January 23, 2009.
39 New York Times, “Brazil is poised to begin WTO protest over ethanol tariffs,” New York Times, July 30 2008, http://www.nytimes.com/2008/07/30/business/worldbusiness/30iht-30ethan.14880834.html (accessed April 11, 2010).
40 Michele Morrone et al., “The Challenges of Biofuels from the Perspective of Small-Scale Producers in Ohio,” Energy Policy 37, 2 (2009): 522-530.
42 United Nations Environment Program,18.
43 A. Milbrandt, A geographic perspective on the current biomass resource availability in the United States, Goldern, CO: National Renewable Energy Laboratory, December 2005, 2.
44 United Nations Environment Program, 17.
45 Petrou and Pappis, 1062.
46 United Nations Environment Program, 18.
47 Petrou and Pappis, 1060.
48 U.S. Environmental Protection Agency, Renewable Fuel, 21-24.
49 United Nations Environment Program, 16-17.
50 Mark Muller, Tammy Yelden, and Heather Schoonover, “Food versus Fuel in the United States: Can Both Win in the Era of Ethanol?” Institute for Agriculture and Trade Policy, 2007.
51 U.S. Environmental Protection Agency and National Renewable Energy Laboratory, State Bioenergy Primer, September 15, 2009, 3.
52 Lyn Jerde, “DNR hands Didion violation notice,” Portage Daily Register, August 21 2009.
53 Stacy Vogel, “More than half of Wisconsin ethanol plants face violations,” The Jainsville Gazette, October 12, 2008.
54 Lyn Jerde,“Didion ethanol facility to grow; new line to be added, and stimulus funds to be used in $11 million project,” Portage Daily Register, March 2, 2010.
55 Terry Devitt, Major bioenergy initiative takes flight in Midwest, Great Lakes Bioenergy Research Center press release, June 26, 2007. http://www.news.wisc.edu/bioenergy/release.html (accessed 3/19/10)
56 Michael Pollan, Second Nature: A Gardener’s Education (NY: Laurel, 1992), 47.
57 Brian Hayes, Infrastructure: A Field Guide to the Industrial Landscape (NY: W. W. Norton & Co., 2005), 104-48.
58 Illinois Corn Association, “A Take of Two Corns Lesson Plans,” Illinois Corn Association, http://www.ilcorn.org/internal.php?q=vprofile&id=434&date=July%2031,%202009&banner=resources (accessed April 11, 2010).
59 Hayes, Infrastructure, 490-1.
60 Doyle and Ziewacz, 2008 Wisconsin Energy Statistics, 3, 20; Matthew Purdy, GIS Inventory Forester with The Campbell Group, LLC., personal communication, March 22, 2010.