ESL Lesson 1
Oil in Our Every Day Life
ESL Lesson 2
The History of Mining
ESL Lesson 3
Economic growth
ESL Lesson 4
Delivery Systems
ESL Lesson 5
Cities and Population Movement
ESL Lesson 6
Recycling
ESL Lesson 7
Rubber
ESL Lesson 8
Farming
Cellulosic Ethanol
Key questions on energy options
Is the energy source sustainable?
Sustainable.
What are the potential negative externalities (effects) of producing/using this
energy source?
Few potential negative externalities depending on the biomass (plant) source.
What is the EROEI?
Unknown
Is it affordable?
Presently, despite (after all of) frequently optimistic (positive) claims, it costs significantly (much) more to produce cellulosic ethanol than to produce corn ethanol.
Are there better alternatives?
Yes.
Are there other special considerations?
There are numerous sources of biomass (plant sources) that could be used to produce cellulosic ethanol.
In summary, are the advantages of the source large enough to justify any
negative consequences?
Time will tell, but cellulosic ethanol did not just come onto the scene. Researchers have been trying to commercialize it for many years without much success. It will require several breakthroughs (new ideas in chemistry and science), none of which are certain (guaranteed) to occur before cellulosic ethanol contributes to our energy requirements.
Due to the lack of commercial cellulosic ethanol plants, the energy return is largely unknown. On the one hand, fossil fuel inputs for growing the biomass will likely be much lower than for corn. However, the ethanol concentration yielded (% given) from a cellulosic ethanol process tends (usually seems) to be significantly (much) lower than the concentration obtained (gained) in conventional ethanol production. A presentation at last year's St. Louis Renewable Energy Conference from Keith Collins, Chief Economist at the USDA, showed that corn ethanol yields 14-20% ethanol, while cellulosic is a paltry (very small amount) 4%.
In addition, more processing steps are required. I have seen EROEI estimates for cellulosic ethanol that range from less than 1 to greater than 8. Based (depending) on the factors mentioned (talked about) here, the true estimate is likely to be closer to 1. The truth is we just won't know until some commercial facilities (factories and distillery plants) are up and running.
I believe that technical improvements will occur with cellulosic ethanol. But many people who don't understand the nature of the challenges (problems with today's technology) assumed that new technology will magically start by itself one day. If I announced that we would be making regular trips to Mars within 10 years, most people would reject this idea because they have some understanding of both the technical difficulty involved, and they understand that the costs would be enormous (very large). Yet these are the same people who have no problem believing that we are going to transition (change) our fossil fuel infrastructure (for cars) to a cellulosic ethanol infrastructure. Yet the technical challenges involved are of the magnitude (equally as difficult and complex) of ferrying (taking) us all back and forth to Mars.
Unlike normal ethanol, whose original raw materials are sugars and starches, cellulosic ethanol's starting raw material is cellulose from plants. Since cellulose cannot be digested by humans, the production of cellulose does not compete with the production of food. The price per ton of the raw material is thus much cheaper than grains or fruits. Also, since cellulose is the main components (parts) of plants, the whole plant can be harvested. This results in much better yields per acre-up to 10 tons, instead of 4 or 5 tons for the best crops of grain.
“We have made it work with straw from barley, wheat, oats, and rice; with cornstalks; with bagasse (remains of sugar cane after crushing) left over from sugar-cane processing; and with chips of hardwoods such as poplar and aspen. There's also research going on with energy crops like switchgrass”. Said Brian Foody of Logen Corporation. You can also use agricultural wastes like corn stover (stalks and leaves) and sugarcane scraps. Industrial and municipal solid wastes like paper sludge; forest industrial wastes like sawdust; and energy crops like switchgrass or hybrid poplars. A few fast-growing trees, shrubs, and grasses stand out as premium candidates for cellulosic conversion.
More information:http://en.wikipedia.org/wiki/Cellulosic_ethanol
http://www.powerenergy.com
http://www.seco.cpa.state.tx.us/re_ethanol_cellulosic.htm
http://news.mongabay.com/2006/0824-purdue2.html
Continue to: Biodiesel
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Rubber
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Bio-fuels and Ethanol
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Liquid Fossil Fuels
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Grain Ethanol
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Sugarcane Ethanol
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Cellulosic Ethanol
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Biodiesel
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Biomass Gasification
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Wind and Solar
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Conservation
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