It is disputed whether corn ethanol as an automotive fuel results in a net energy gain or loss. As reported in "The Energy Balance of Corn Ethanol: an Update,"[48] the energy returned on energy invested (EROEI) for ethanol made from corn in the U.S. is 1.34 (it yields 34% more energy than it takes to produce it). Input energy includes natural gas based fertilizers, farm equipment, transformation from corn or other materials, and transportation. However, other researchers report that the production of ethanol consumes more energy than it yields.[49][50] In comparison, sugar cane ethanol EROEI is at around 8 (it yields 8 joules for each joule used to produce it).[citation needed] Recent research suggests that cellulosic crops such as switchgrass provide a much better net energy production than corn, producing over five times as much energy as the total used to produce the crop and convert it to fuel.[51] If this research is confirmed, cellulosic crops will most likely displace corn as the main fuel crop for producing bioethanol.
Michael Grunwald reports that one person could be fed 365 days "on the corn needed to fill an ethanol-fueled SUV".[52] He further reports that though "hyped as an eco-friendly fuel, ethanol increases global warming, destroys forests and inflates food prices." Environmentalists, livestock farmers, and opponents of subsidies say that increased ethanol production won"t meet energy goals and may damage the environment, while at the same time causing worldwide food prices to soar. Some of the controversial subsidies in the past have included more than $10 billion to Archer-Daniels-Midland since 1980.[53][neutrality disputed] Critics also speculate that as ethanol is more widely used, changing irrigation practices could greatly increase pressure on water resources. In October 2007, 28 environmental groups decried the Renewable Fuels Standard (RFS), a legislative effort intended to increase ethanol production, and said that the measure will "lead to substantial environmental damage and a system of biofuels production that will not benefit family farmers...will not promote sustainable agriculture and will not mitigate global climate change."[54][55]
Recent articles have also blamed subsidized ethanol production for the nearly 200% increase in milk prices since 2004,[56] although that is disputed by some[citation needed]. Especially since the price of fuel has driven up the costs to cultivate, grow, harvest, ship, refine, bring to market, etc, all commodities including; but not limited to, milk. Not to mention the presence of speculators, and the recent growing interest in the commodities market by investors who have been scared away from a falling stock market.
Ethanol production uses the starch portion of corn, but the leftover protein can be used to create a high-nutrient, low-cost animal feed.[57]
In 2007 the United Nations" independent expert on the right to food, called for a five-year moratorium on biofuel production from food crops, to allow time for development of non-food sources. He called recent increases in food costs because of fuel production, such as the quadrupling of world corn price in one year, a growing "catastrophe" for the poor.[58] In February 2007, riots occurred in Mexico because of the skyrocketing price of tortillas. Ethanol has been credited as the reason for this increase in food prices[59]. The demand for corn has had a rippling effect on many corn-based products, like tortillas. The effects of ethanol and the increasing cost of food have also been felt in Pakistan, Indonesia, and Egypt.[60]
Oil has historically had a much higher EROEI than corn produced ethanol, according to some[citation needed]. However, oil must be refined into gasoline before it can be used for automobile fuel. Refining, as well as exploration and drilling, consumes energy. The difference between the energy in the fuel (output energy) and the energy needed to produce it (input energy) is often expressed as a percent of the input energy and called net energy gain (or loss). Several studies released in 2002 estimated that the net energy gain for corn ethanol is between 21 and 34 percent. The net energy loss for MTBE is about 33 percent. When added to gasoline, ethanol can replace MTBE as an anti-knock agent without poisoning drinking water as MTBE does. In Brazil, where the broadest and longest ethanol producing experiment took place, improvements in agricultural practices and ethanol production improvements led to an increase in ethanol net energy gain from 300% to over 800% in recent years.[citation needed] It must be noted that Brazil produces ethanol more efficiently because its primary input is the sugar from sugar cane rather than starches from corn. Consuming known oil reserves is increasing oil exploration and drilling energy consumption which is reducing oil EROEI (and energy balance) further.[61]
Opponents claim that corn ethanol production does not result in a net energy gain or that the consequences of large scale ethanol production to the food industry and environment offset any potential gains from ethanol. It has been estimated that "if every bushel of U.S. corn, wheat, rice and soybean were used to produce ethanol, it would only cover about 4% of U.S. energy needs on a net basis."[62] Many of the issues raised could likely be fixed by techniques now in development that produce ethanol from agricultural waste, such as paper waste, switchgrass, and other materials, but EIA Forecasts Significant Shortfall in Cellulosic Biofuel Production Compared to Target Set by Renewable Fuel Standard.[63]
Proponents cite the potential gains to the U.S. economy both from domestic fuel production and increased demand for corn. Optimistic calculations project that the United States is capable of producing enough ethanol to completely replace gasoline consumption.[citation needed] In comparison, Brazil"s ethanol consumption today covers more than 50% of all energy used by vehicles in that country.
In the United States, preferential regulatory and tax treatment of ethanol automotive fuels introduces complexities beyond its energy economics alone. North American automakers have in 2006 and 2007 promoted a blend of 85% ethanol and 15% gasoline, marketed as E85, and their flex-fuel vehicles, e.g. GM"s "Live Green, Go Yellow" campaign.[64] The apparent motivation is the nature of U.S. Corporate Average Fuel Economy (CAFE) standards, which give an effective 54% fuel efficiency bonus to vehicles capable of running on 85% alcohol blends over vehicles not adapted to run on 85% alcohol blends.[65] In addition to this auto manufacturer-driven impetus for 85% alcohol blends, the United States Environmental Protection Agency had authority to mandate that minimum proportions of oxygenates be added to automotive gasoline on regional and seasonal bases from 1992 until 2006 in an attempt to reduce air pollution, in particular ground-level ozone and smog.[66] In the United States, incidents of methyl tert(iary)-butyl ether (MTBE) groundwater contamination have been recorded in the majority of the 50 states,[67] and the State of California"s ban on the use of MTBE as a gasoline additive has further driven the more widespread use of ethanol as the most common fuel oxygenate.[68]
A February 7, 2008 Associated Press article stated, "The widespread use of ethanol from corn could result in nearly twice the greenhouse gas emissions as the gasoline it would replace because of expected land-use changes, researchers concluded Thursday. The study challenges the rush to biofuels as a response to global warming."[69]
One acre of land can yield about 7,110 pounds (3,225 kg) of corn, which can be processed into 328 gallons (1240.61 liters) of ethanol. That is about 26.1 pounds (11.84 kg) of corn per gallon.
Much overlooked in most discussions about ethanol from corn are the by-products from the production of ethanol. Depending on the way it is processed, the processing yields several beneficial products, some of which are used for food production and feedstocks.
Ethanol may be used as a fuel to power Direct-ethanol fuel cells (DEFC) in order to produce electricity and the by-products of water (H2O) and carbon dioxide (CO2).[70] Platinum is commonly used as an anode in such fuel cells in order to achieve a power density that is comparable to competing technologies. Until recently the high price of platinum has been cost prohibitive. A company called Acta Nanotech has created platinum free nanostructured anodes using more common and therefore less expensive metals.[71] A vehicle using a DEFC and non-platinum nanostructured anodes was used in the Shell Eco-Marathon 2007 by a team from Offenburg Germany which achieved an efficiency of 2716 kilometers per liter (6388 miles per gallon).[72]
Ethanol was commonly used as fuel in early bipropellant rocket vehicles, in conjunction with an oxidizer such as liquid oxygen. The German V-2 rocket of World War II, credited with beginning the space age, used ethanol, mixed with water to reduce the combustion chamber temperature.[73][74] The V-2"s design team helped develop U.S. rockets following World War II, including the ethanol-fueled Redstone rocket, which launched the first U.S. satellite.[75] Alcohols fell into general disuse as more efficient rocket fuels were developed.[74]
Ethanol is the principal psychoactive constituent in alcoholic beverages, with depressant effects on the central nervous system. It has a complex mode of action and affects multiple systems in the brain, most notably ethanol acts as an agonist to the GABA receptors.[76] Similar psychoactives include those which also interact with GABA receptors, such as gamma-hydroxybutyric acid (GHB).[77] Ethanol is metabolized by the body as an energy-providing carbohydrate nutrient, as it metabolizes into acetyl CoA, an intermediate common with glucose metabolism, that can be used for energy in the citric acid cycle or for biosynthesis.
Alcoholic beverages vary considerably in their ethanol content and in the foodstuffs from which they are produced. Most alcoholic beverages can be broadly classified as fermented beverages, beverages made by the action of yeast on sugary foodstuffs, or as distilled beverages, beverages whose preparation involves concentrating the ethanol in fermented beverages by distillation. The ethanol content of a beverage is usually measured in terms of the volume fraction of ethanol in the beverage, expressed either as a percentage or in alcoholic proof units.
Fermented beverages can be broadly classified by the foodstuff from which they are fermented. Beers are made from cereal grains or other starchy materials, wines and ciders from fruit juices, and meads from honey. Cultures around the world have made fermented beverages from numerous other foodstuffs, and local and national names for various fermented beverages abound.
Distilled beverages are made by distilling fermented beverages. Broad categories of distilled beverages include whiskeys, distilled from fermented cereal grains; brandies, distilled from fermented fruit juices, and rum, distilled from fermented molasses or sugarcane juice. Vodka and similar neutral grain spirits can be distilled from any fermented material (grain or potatoes are most common); these spirits are so thoroughly distilled that no tastes from the particular starting material remain. Numerous other spirits and liqueurs are prepared by infusing flavors from fruits, herbs, and spices into distilled spirits. A traditional example is gin, which is created by infusing juniper berries into a neutral grain alcohol.
In a few beverages, ethanol is concentrated by means other than distillation. Applejack is traditionally made by freeze distillation, by which water is frozen out of fermented apple cider, leaving a more ethanol-rich liquid behind. Eisbier (more commonly, eisbock) is also freeze-distilled, with beer as the base beverage. Fortified wines are prepared by adding brandy or some other distilled spirit to partially-fermented wine. This kills the yeast and conserves some of the sugar in grape juice; such beverages are not only more ethanol-rich, but are often sweeter than other wines.
Alcoholic beverages are sometimes used in cooking, not only for their inherent flavors, but also because the alcohol dissolves hydrophobic flavor compounds which water cannot.
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