OK, can we please stop pretending biofuel made from corn is helping the planet and the environment? The United Nations Intergovernmental Panel on Climate Change released two of its Working Group reports at the end of last month (WGI and WGIII), and their short discussion of biofuels has ignited a fierce debate as to whether they’re of any environmental benefit at all.
The IPCC was quite diplomatic in its discussion, saying “Biofuels have direct, fuel‐cycle GHG emissions that are typically 30–90% lower than those for gasoline or diesel fuels. However, since for some biofuels indirect emissions—including from land use change—can lead to greater total emissions than when using petroleum products, policy support needs to be considered on a case by case basis” (IPCC 2014 Chapter 8).
In 2013 the U.S. used 4.7 billion bushels of corn (40% of the harvest) to produce over 13 billion gallons of ethanol fuel. Source: YES! Magazine
The summary in the new report also states, “Increasing bioenergy crop cultivation poses risks to ecosystems and biodiversity” (WGIII).
The report lists many potential negative risks of development, such as direct conflicts between land for fuels and land for food, other land-use changes, water scarcity, loss of biodiversity and nitrogen pollution through the excessive use of fertilizers (Scientific American).
The International Institute for Sustainable Development was not so diplomatic, and estimates that the CO2 and climate benefits from replacing petroleum fuels with biofuels like ethanol are basically zero (IISD). They claim that it would be almost 100 times more effective, and much less costly, to significantly reduce vehicle emissions through more stringent standards, and to increase CAFE standards on all cars and light trucks to over 40 miles per gallon as was done in Japan just a few years ago.
With more than 60 nations having biofuel mandates, the competition between ethanol and food has become a moral issue. Groups like Oxfam and the Environmental Working Group oppose biofuels because they push up food prices and disproportionately affect the poor.
Most importantly, the new IPCC report is a complete about-face for the UN’s Panel. Its 2007 report was broadly condemned by some environmentalists for giving the green light to large-scale biofuel production, resulting in environmental and food supply problems.
The general discussion on biofuels has changed over the last few years. In December, Senators Feinstein (D-CA) and Coburn (R-OK) introduced a bill that would eliminate the corn ethanol mandate within the Federal Renewable Fuel Standard (Oil&Gas Journal) that requires blending ethanol into gasoline at increasing levels over the next decade. It was met with stiff opposition from heavily agricultural states, but had strong support from the petroleum industry. However, now that the tax credit and import tariffs have expired and ethanol is holding its own economically, it remains to be seen if the industry can stand up to this pressure.
So where is the U.S. today in corn ethanol space?
In 2000, over 90% of the U.S. corn crop went to feed people and livestock, many in undeveloped countries, with less than 5% used to produce ethanol. In 2013, however, 40% went to produce ethanol, 45% was used to feed livestock, and only 15% was used for food and beverage (AgMRC).
The United States will use over 130 billion gallons of gasoline this year, and over 50 billion gallons of diesel. On average, one bushel of corn can be used to produce just under three gallons of ethanol. If all of the present production of corn in the U.S. were converted into ethanol, it would only displace 25% of that 130 billion.
But it would completely disrupt food supplies, livestock feed, and many poor economies in the Western Hemisphere because the U.S. produces 40% of the world’s corn. Seventy percent of all corn imports worldwide come from the U.S. Simply implementing mandatory vehicle fuel efficiencies of 40 mpg would accomplish much more, much faster, with no collateral damage.
In 2014, the U.S. will use almost 5 billion bushels of corn to produce over 13 billion gallons of ethanol fuel. The grain required to fill a 25-gallon gas tank with ethanol can feed one person for a year, so the amount of corn used to make that 13 billion gallons of ethanol will not feed the almost 500 million people it was feeding in 2000. This is the entire population of the Western Hemisphere outside of the United States.
In 2007, the global price of corn doubled as a result of an explosion in ethanol production in the U.S. Because corn is the most common animal feed and has many other uses in the food industry, the price of milk, cheese, eggs, meat, corn-based sweeteners and cereals increased as well. World grain reserves dwindled to less than two months, the lowest level in over 30 years.
Additional unintended effects from the increase in ethanol production include the dramatic rise in land rents, the increase in natural gas and chemicals used for fertilizers, over-pumping of aquifers like the Ogallala that serve many mid-western states, clear-cutting forests to plant fuel crops, and the revival of destructive practices such as edge tillage. Edge tillage is planting right up to the edge of the field thereby removing protective bordering lands and increasing soil erosion, chemical runoff and other problems. It took us 40 years to end edge tillage in this country, and overnight ethanol brought it back with a vengeance.
Most fuel crops, such as sugar cane, have problems similar to corn. Because Brazil relied heavily on imported oil for transportation, but can attain high yields from crops in their tropical climate, the government developed the largest fuel ethanol program in the world in the 1990s based on sugar cane and soybeans.
Unfortunately, Brazil is clear-cutting almost a million acres of tropical forest per year to produce biofuel from these crops, and shipping much of the fuel all the way to Europe. The net effect is about 50% more carbon emitted by using these biofuels than using petroleum fuels (Eric Holt-Giménez, The Politics of Food). These unintended effects are why energy policy and development must proceed holistically, considering all effects on global environments and economies.
So why have we pushed corn ethanol so heavily here in the U.S.? Primarily because it was the only crop that had the existing infrastructure to easily modify for this purpose, especially when initially incentivized with tax credits, subsidies and import tariffs. Production, transportation and fermentation could be adapted quickly by the corn industry, unlike any other crop.
We should remember that humans originally switched from biomass to fossil fuels because biomass was so inefficient, and took so much energy and space to produce. So far technology has not reversed these problems sufficiently to make widespread use beneficial.
What else can we use to produce biofuel?
Like Switchgrass, Napier grass (shown here growing in Alabama) is a more environmentally friendly source for ethanol than corn, with a higher energy density. Source: NREL, Warren Gretz (David Bransby shown)
Two leading strategies involve ethanol production from the degradation of cellulosics, and biodiesel production from algae.
The common alcohol, ethanol, has been harnessed by humans for millennia, made through the microbial conversion of biomass materials, typically sugars, through fermentation. The process starts with a solution of fermentable sugars, fermented to ethanol by microbes, and then the ethanol is separated and purified by distillation.
Fermentation involves microorganisms, typically yeasts, that evolved billions of years ago before Earth’s atmosphere contained oxygen, to use sugars for food and in the process produced ethanol, CO2 and other byproducts:
(sugar) C6H12O6 → 2 CH3CH2OH + 2 CO2 (ethanol + carbon dioxide)
Microorganisms typically use 6-carbon sugars and their precursors, glucose and sucrose. But because sugars and starches are foods, a better alternative for ethanol production should be from non-food cellulosic materials, such as paper, cardboard, wood, and other fibrous plant material. Switchgrass and napier grass have been studied extensively as the best alternatives.
Cellulosics are abundant and much of the supply is considered waste. Cellulosics are comprised of lignin, hemicellulose, and cellulose. Lignin provides structural support for the plant and encloses the cellulose and hemicellulose molecules, making it more difficult to process for fuel.
Thus, efficiently making ethanol out of cellulosics requires a different approach than for corn. They can either be reacted with acid (sulfuric is most common), degraded using enzymes produced from microbes, or heated to a gas and reacted with chemical catalysts (thermo-chemical). Each has its variations, some can be combined, and all are attempting to be commercialized. Still, these processes are stuck at about twice the price per gallon produced compared to corn. Recently, special microorganisms have been genetically engineered to ferment these materials into ethanol with relatively high efficiency.
It’s no wonder we just went with corn!
Another less discussed biofuel strategy is biodiesel replacing petroleum diesel. Biodiesel is made by combining almost any oil or fat with an alcohol such as ethanol or methanol.
Biodiesel can be run in any diesel engine without modification and produces less toxic emissions and particulates than petroleum diesel. It causes less wear and tear on engines, and increases lubricity and engine efficiency, and releases about 60% less CO2 emissions than petroleum diesel.
Rudolf Diesel originally developed the diesel engine to run on diesel from food oils such as peanut and soybean, but animal fats and any other natural oil can be used. However, almost a hundred years ago, the need for fuel outstripped the supply of natural oils and petroleum become the only abundant source available.
Making biodiesel from any oil is relatively easy. The trick is to find a good source of bio-oil, like fast-food restaurants, or algae. Source: CEHMM, Carlsbad NM
The most common natural oils used are rapeseed and canola oil, but a particularly promising candidate is oil from algae. Algae production uses non-productive land and brine water and produces over 20 times the oil production of any food crop. An acre of algae can produce almost 5,000 gallons of biodiesel. It does not compete with food crops for arable land or potable water and could produce over 60 billion gallons/yr that would replace all petroleum-based diesel in the U.S.
However, all algae production facilities presently sell their crops to the food and cosmetic industry at a much greater profit than they would get from the fuel industry.
I guess for biofuels, as for any other source, there’s just no such thing as a free lunch.
[Note: Thanks to Eric and other commenters for pointing out some errors, especially my failing to mention the tax credits and tariffs have expired]
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