Alternative Fuels

What will you fill up your car with in five to ten years? It's hard to say. Several different alternatives to petroleum and diesel, or ways to economize on them, have come forward in the past few years, and each has its own pluses and minuses.
Experts warn that it won't be easy to get off of petroleum or reduce how much the world uses. The amount of energy per liter derived from petroleum is far better than most of the alternatives, a worldwide infrastructure based on it already exists, and people tend to be lazy--seeking out alternative fuels takes some effort.
If oil drops below $55 a barrel, most of these alternatives stop becoming attractive, says Dan Arvizu, director of the National Renewable Energy Laboratory. And the Organization of the Petroleum Exporting Countries is watching what is going on in alternative fuels and can gauge oil prices accordingly.
"We do have a problem with how serious we are about our energy challenges," he said.
Global warming and improving technology, however, are making the alternatives more realistic all the time. Here's a guide to the main alternatives.
1. Ethanol
What: Ethanol is an alcohol produced out of corn, sugar cane or other food crops. During the production process, the plant material goes through several stages of heating and reduction. Ethanol is typically mixed with gasoline. Some cars can run on a mix of 85 percent ethanol and 15 percent gas, but ethanol is most commonly used as an additive in smaller percentages. Forty-seven percent of U.S. drivers today use some form of ethanol, but they usually only put small amounts in their cars: many states now use it for a substitute for MTBE, a common fuel additive with potential health risks to humans and other animals.
Pros: Ethanol pollutes less than regular gas. And we already know how to make it in large volumes. Brazil uses ethanol made from sugar cane extensively. Investors are pouring billions of dollars into ethanol refineries in the U.S. There are 109 ethanol plants in the U.S. and 40 new projects coming on line, according to Michael Eckhart, president of American Council on Renewable Energy (ACORE).
Cons: Where to begin? First, food crops aren't an ideal fuel source. An acre of corn produces 480 gallons of ethanol, according to Paul McCroskey, chief financial officer at Ceres, which makes enzymes for the fuel industry. That's a lot of land.
Ethanol only puts out two-thirds the energy of gas, so car mileage is lower on ethanol. Ethanol production also generates tons of carbon dioxide, which, if it's not captured turns into greenhouse gases. Producing ethanol also requires lots of energy. It's popular, say some, because farmers love it, and they tend to show up on Election Day.
To top it off, the price of corn is climbing, while gas prices are declining. In January 2006, ethanol sold for $3 a barrel, while a bushel of corn cost $2. Now, ethanol sells for $2 per barrel and corn goes for $4.20 a bushel, according to ACORE. "We have seen the most profitable space in the fuel business disappear in a year," said Eckhart. OPEC, he added, will lower oil prices to put pressure on the ethanol industry.
2. Cellulosic ethanol
What: Cellulosic ethanol is also an alcohol, but it's made out of wood chips, corn stalks and agricultural waste products. Some scientists also believe cellulosic ethanol can be produced out of plants like switchgrass that require little fertilizer and water and could grow in the windswept plains of South Dakota.
Pros: The feedstock dilemma essentially disappears. The vegetable matter used in cellulosic ethanol has almost no value, which will mean margins won't get compressed by commodity price shifts, and critics can't argue that food crops in a hungry world are going to cars. Mascoma, Dyadic International and other companies are also devising ways to convert the high-cellulose waste matter into alcohol with microbes and enzymes, there by cutting production costs and total greenhouse gas emissions.
The goal is to get cellulosic ethanol to the point where the "real" cost per gallon will run you $1.62, according to Arvizu. (The real cost is how much ethanol it will take to go as far as a gallon of gas will take you. Typically, 1.67 gallons of ethanol equal 1 gallon of gas.) By contrast, the "real" cost of standard ethanol is close to $3.50 or more now, he added.
Cons: It pretty much only exists in labs right now, but larger-scale production is coming. Mascoma plans to open a trial plant that can produce 500,000 gallons a year by the end of this year.
"It (commercial cellulosic ethanol production) used to be five or six years out, but we could get it done in three years. The key is being able to build a plant that can do one to two million gallons," said William Baum, executive vice president of Diversa, which finds microbes in exotic locales and puts them to work.
Like regular ethanol too, cellulosic faces a retail problem: the stations emblazoned with Shell or ChevronTexaco signs won't be clamoring to carry it. That's partly why only 1 percent of U.S. stations--mostly independents or pumps at grocery stores--serve ethanol.
3. Biodiesel
What: It's diesel fuel made out of soy, palm or other vegetable oils. The drippings from a deep fat fryer can run a diesel car, as long as you filter it and heat up the oil to make the oil more viscous. Biodiesel refiners essentially do the filtering for consumers. There are 85 biodiesel plants in the U.S. and 65 in construction, according to ACORE.
Pros: It's got far fewer economic and environmental hurdles than ethanol, says Martin Tobias, a former Microsoft exec who now runs Imperium Renewables, a biodiesel maker. Diesel cars are very popular in Europe, and several manufacturers make high-mileage diesel cars. Some truck and bus makers already produce diesel hybrid trucks. Biodiesel could be sold to those people right now. And since industrial diesel users buy their fuel directly, they don't have to worry about corporate service stations snubbing biodiesel altogether.
Finally, biodiesel puts out far less carbon gases. Sulfur can be a problem with soy-based biodiesel, but Tobias says it can be contained.
Cons: Farming sometimes isn't the most eco-friendly activity, and some worry that a surge in demand for palm oil will lead to slash-and-burn agriculture and pollution in the tropics. Advocates, though, say that farmers are tackling this problem. One group in Colombia is growing biodiesel feedstock on old coca plantations. The rising popularity of biodiesel is expected to impact the cost of food oil.
Even after the new facilities get built, biodiesel is a drop in the bucket of the world's fuel needs. There are only 150 million gallons of the stuff produced a year in the U.S. and, although that number will climb to 250 gallons this year, the U.S. consumes about 62 billion gallons of diesel a year.
(Trecho do texto original : "FAQ: Guide to Alternative Fuels")
Fonte : CNET News. com - http//news.com.com

Vocabulário:
altogether - completamente
amount - quantia
bucket - balde
bushel - alqueire (medida de cereais)
clim - ascenção
crop - colheita
devising - legado
dripping - encharcado
emblazon - ornar
environmental - ambiente
feedstock - estoque de alimentos
fill up - encher completamente
forward - incentivar
fryer - ave comestível para fritar
gauge - critério
greenhouse - estufa
heat - calor
however - de qualquer modo
hurdle - obstáculo
lazy - preguiçoso
mileage - milhagem
pouring - despejar
pump - bomba
rising - ascenção
several - vários
slash - cortes
nub - desprezar
stalks - caule
switchgrass - gramíneas
warn - previnir
waste - desperdício
windswept- exposto ao vento
worldwide - mundial
worry - preocupação

Questões:
1 - O Petróleo já é considerado uma fonte de energia e combustível esgotável. que tem sido desenvolvido pelos especialistas e o que torna estas novas medidas parte de um processo demroado?
2- Quais as matérias-primas usadas para produzir Etanol? Nos EUA, essa fonte é utlizada? Como?
3- Quais são as desvantagens do uso de Etanol em carros?
4- As fontes de matérias-primas de Etanol de celulose e do Biodiesel são similiares. Qual é a origem dessas fontes?
5- Em relação ao Aquecimento Global, qual combústivel colabora menos com a liberação dos gases do efeito estufa - Biodiesel ou Etanol de celulose? Justifique.

Componentes do Grupo
Aline Brito - nº 3
Amanda Nicoli - nº 6
Bruno Chescon - nº 12
César - nº 23
Karine - nº 39