What are the pluses and minuses of using ethanol as energy?

Answer 1

pluses:

ethanol is an altenitive energy. this means that if we use ethanol we become less dependant on petrolum.

minuses:

if more and more people become dependant on ethanol we, the US, will have to grow more corn to satisfy that demand.

Answer 2

the positives of ethanol is that ethanol is made of corn and i like corn, so when i put ethanol in my car its like my car is eating it to, so how awsome is that.

A Little More Info

Ethanol has been touted as a partial substitute for gasoline in internal combustion engines. Since it can be produced from plant materials, it is considered a renewable "green" resource. In the US, ethanol use has been promoted as a way to reduce imports of foreign oil.

However in recent years, some in the US have publicly abandoned their support for ethanol. Notably, former Vice President Al Gore, who cast the tie-breaking vote in the Senate in 1995 that allowed the government to mandate ethanol in gasoline, recently recanted his support for ethanol. The Sierra Club also opposes large-scale production of ethanol.

In an economic sense, the current production costs for ethanol are such that it is more expensive than gasoline. The US federal government has moved to solve that problem in three ways. First, it gives a subsidy of 45 cents/gallon to refiners for every gallon of ethanol they blend into their gasoline. Second, it has mandated that refiners modify their facilities to facilitate blending ethanol with their gasoline and pressured carmakers to redesign their cars to use blended fuels. And third, it has place steep tariffs on imported ethanol to protect domestic grain markets and encourage American farmers and ethanol producers to grow corn and make ethanol.

In other words, the US government has in effect created a market for ethanol where one did not exist before. In North America, almost all ethanol is made from corn. About 40% of the corn grown in the US is made into ethanol.

One obvious result of this corn "explosion" is a major shift in farm activity, commodity markets, and the price of commodity crops in the US and abroad. Massive government support for ethanol led to a flurry of ethanol plant construction in the US over the past twenty years; there are nearly 200 active large-scale ethanol distilleries today, mostly in the Midwest. (Twenty years ago, there were essentially none.) As these plants went on line, one after another, demand for corn skyrocketed, and predictably the price of corn shot up. Farmers quickly took acreage from other crops and put it in corn. This caused a "domino" effect in the prices of other commodity crops, such as wheat and soybeans, and in silage crops, such as hay. As acreage shifted to corn, the supply of these other crops dwindled and prices climbed accordingly.

Food prices worldwide have been driven up by this artificially created and maintained market for ethanol. Especially in the US, there have been sharp hikes in the prices of many staple products, including milk, meats, bread, flour, which are either directly derived from crop grains or rely on crop grains as feedstocks. Heavily-sweetened items such as soda pop and candy have been hit especially hard. US government tariffs on imported cane sugar have been in place for generations; as a direct result, in the US cane sugar costs twice what it does in Canada or Mexico. Over the years, this has caused US-based companies -- candymakers in particular -- to move their US operations to other countries. But mainly the tariffs caused most food producers who had once used cane sugar to switch to the much-cheaper corn syrup. Now with a government-sponsored ethanol market driving up the price of corn -- and corn syrup -- practically any foodstuff made in the US that is sweetened at all, from breakfast cereal to ice cream to doughnuts to chocolate cake, is more expensive to make, and consequentially costs more at market.

As an additive to gasoline, ethanol has been criticized for a number of reasons. It strongly attracts moisture, which can lead to fuel contamination and corrosion of engine parts. It attacks some plastics that have been traditionally used as engine components, fuel lines and fuel storage containers. Although it acts as an octane booster when blended with gasoline, it has not generally been used to boost octane, but rather to allow a lower-grade gasoline to achieve a target octane rating.

Compared to gasoline, ethanol yields about 34% less energy when burned. Engines can be designed to take advantage of the higher octane that ethanol can produce, but the vast majority of automobiles do not have such engines, and suffer decreased fuel economy when burning an ethanol blend. The higher cost of engines that can take advantage of the ethanol octane boost -- with things like variable-boost turbochargers -- dictates that they will not become the norm.

In terms of energy invested vs. energy yield, from cornfield to gas tank, a gallon of ethanol requires about 95,000 BTU to produce, but generates only about 77,000 BTU when burned. By comparison, a gallon of gasoline can be made with only about 22,000 BTU and will generate over 120,000 BTU when burned.

As a practical solution to foreign oil imports in the US, ethanol will never have a significant effect as long as it's corn-based. The US simply does not have enough arable land to grow enough corn to produce enough ethanol to significantly replace foreign oil imports, even if we learn to live without every other domestically-grown food crop and design cars that burn nothing but ethanol. As it stands, after massive government intervention and an investment in ethanol that likely measures in the trillions of dollars, we have made no measurable dent in oil imports.