However, the industry can head in a direction that would leave the accusations baseless. This article depicts an avenue of growth that greatly increases industry profit while eliminating negative connotations permanently.
Many promised future technologies may not materialize, or else may cause unexpected harm. Plug-in hybrids would save a large amount of crude oil but only by dramatically increasing the use of coal to make electricity. Any oil saved in one country is likely to be used elsewhere, so the world would end up burning the same amount of oil and a huge additional amount of coal—a scenario for catastrophic climate change. Although solar cells will have important local application, electricity generated for the nation by solar cell arrays in the desert Southwest is unlikely. Most of the energy is lost when transforming low-voltage direct current put out by solar cells to high-voltage alternating current for long distance transmission.
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If done properly, ethanol can pick up much of the slack in a way that’s sustainable, largely through a better match between suitable local biomass and a specific type of cellulosic ethanol production.
Cellulosic Ethanol, Limited Agricultural AcreageThe United States needs a cellulosic production process that uses little energy per unit of ethanol produced (i.e., high energy gain). Infinite Renewable Energy has developed a microorganism-based, low-temperature, low-pressure process with an energy gain of 11:1 that generates almost no pollution per unit of ethanol produced. The cost of producing ethanol using this process is 70 cents per gallon. Such processes tend to be low cost and require low energy inputs, but they must also have a short cycle time to be commercialized, which takes some doing.
Some microorganism-based cellulosic processes can use mixtures of all types of biomass or cellulose including old newspapers and the organic portion of garbage, which is the third-largest source of the greenhouse gas methane in the atmosphere.
Using forage sorghum, which grows across much of the nation, less than 10 percent of U.S. farm acreage would produce enough biomass to replace all U.S. imported oil with cellulosic ethanol.
Other high-yielding ethanol crops that can be grown in the southern United States include sugarcane and a less water-intensive miscanthus/sugarcane hybrid developed at Texas A&M that yields an estimated 10,000 gallons of cellulosic ethanol per acre annually, assuming 90 percent conversion of cellulose.
Cellulosic ethanol requires processing of so much biomass per unit of ethanol that it should be grown and transported no further than 20 miles from the distillery, or transportation (and energy) costs become excessive. This, in turn, dictates a distillery size between 20 MMgy and 50 MMgy. Economics therefore encourage local production by smaller distilleries and local, or nearly local, consumption of ethanol.
Achieving Carbon Neutrality
Ethanol can be produced in a carbon negative manner (“Coupling Carbon Sequestration with Novel Cellulosic Ethanol Technology,” December 2006 Ethanol Producer Magazine), but even without that ethanol made by a low energy process with suitable biomass grown within 20 miles of the distillery will be almost carbon neutral. The only reason ethanol is not carbon neutral is the fuel and energy-intensive materials used to cultivate and harvest biomass, and the energy used to transport the biomass and convert it into ethanol. Biofuel crops requiring little cultivation, which also reduces production costs, are thus desired. Weeds grow without any cultivation and some are prime candidates for cellulosic ethanol.
The cellulosic process can be made even closer to carbon neutral. Lignin, another easily separated component of biomass, if burned as fuel to power the ethanol-making process, introduces no fossil fuel carbon to increase the carbon positive nature of ethanol production, according to Argonne National Laboratories’ “Well-to-Wheel Energy Use and Greenhouse Gas Emission of Advanced Fuel/Vehicle Systems” report released in June 2001. The microorganism-based process needs so little energy that it can be powered by the lignin in the same biomass used to make a particular batch of ethanol.
The minerals left over after making ethanol can be returned to the local fields from which they came. A crop rotation cycle of food crop, biomass and fallow would enable sustainable production of both biomass and food, provided climate change does not become pronounced. The result of the described cost and energy optimizations would produce ethanol that is almost carbon neutral.
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