Check the next page for more facts and the pros and cons of ethanol production.
Renewable energy ethanol (ethyl alcohol) is the same type of alcohol found in alcoholic beverages. Ethanol is distilled and extracted from plants high in
sugars and starches such as corn, and sugar cane. Most ethanol produced today is used for transport.
Ethanol from Corn
The US tends to produce ethanol from corn feed stocks. At the present, an area about the size of the state of Ohio is covered with corn. Ethanol is produced from that corn at one of about 200 plants in the USA. The dry mill process is shown below.
Bushels of corn per gallon of ethanol: 2.65 gallons per bushel, wet mill process; 2.75 gallons per bushel, dry mill process. Cost estimates to produce ethanol from corn using either process varies
from about $1.25 to $1.75 per gallon.
Ethanol from Sugar
One ton of sugar cane can be used to produce around 20 US gallons of ethanol. A ton of molasses from sugar cane/beet produces nearly 70 gallons. A ton of refined sugar can produce some 140 gallons or 3.33 barrels.
However, the total cost per gallon of producing ethanol from sugar cane is about $2.40. The cost of producing ethanol from molasses is just $1.25 per gallon.
Brazil manufacturers favor the use of sugar cane to produce ethanol.
Cellulosic Ethanol
Ethanol can de derived from biomass other than corn and sugar. Biomass for ethanol feed stock can be waste plant matter, corn stalks, wood chips, paper pulp, and some grasses. The grasses can be grown on marginal lands. Research is underway.
Ethanol Use
Most of the ethanol produced today is blended with gasoline for transport. Ethanol has a lower energy density than gasoline. The old Ford model T would run on ethanol alone. However, only a few vehicles today will run on straight alcohol. Ethanol is blended in different amounts from gasohol (10% ethanol) up to about an 85/15 alcohol/gas mix. This is E85, though winter blend E85 may actually be 70/30. Flexible Fuel vehicles (FFVs) are designed to use an E85 blend.
Many FFVs however experience reduced fuel economy (up to -30%) running on ethanol blends.
So, the E85 vehicle needs more fuel to go the same distance. E85 is priced lower than pure gasoline, but the price may need to be up to 30% less to break even.
Ethanol Production Volumes
Most ethanol is used for transportation. Most transport is powered by oil. Most oil is reported in terms of barrels. Most ethanol production, however, is reported in US gallons. To make comparisons, we have converted gallons to barrels.
The USA and Brazil produce the most ethanol and together produce close to 90% of the world total. Imported E85 as a fuel is widely used in Sweden. Ethanol is also commonly marketed in Ireland and Finland.
Asian and Latin American countries are rising producers of ethanol. Cuba has the capacity to manufacture as much as 3.2 billion gallons of ethanol annually from its sugar crop.
Looking at the table below, we see that world ethanol production is now over half a million barrels per year. Within the next 8 years, the total is projected to double to nearly one billion barrels.
World petroleum use is at about 30 billion barrels per year and rising. Assuming that world demand rises to 35 billion barrels by 2019, ethanol would then provide 1/35 of liquid hydrocarbon energy. These are only estimates, but give a view of the relative amount of ethanol use today and in the future.
The USDA forecasts record corn production for 2011/12 at some 14.3 billion bushels. At 2.7 gallons per bushel, this gives close to 920 million barrels of ethanol.
Ethanol Production Facts
Ethanol is a renewable energy source since it comes from annual crops like corn and sugar cane. However, to produce large volumes of ethanol takes signficant volumes of water and fertilizer, and vast tracts of land.
Water use requirement for growing corn - about 785 gallons of water per gallon of ethanol
Water use requirement for processing (dry mill process) ethanol - 4 gallons water per gallon of ethanol
Land requirement for growing the corn - 175 bushels of corn per acre to make 472.5 gallons of ethanol
Global Ethanol production is shown on the U.S. DOE
Graph below right.
