 |
| Ethanol Octane Rating is Higher than Gasoline Image Source: Dr. Penny Pincher |
What is Ethanol?
Ethanol is grain alcohol. This is the same type of alcohol found in alcoholic beverages such as beer, wine, and spirits. Ethanol is produced by fermentation of crops such as corn or sugar cane. Most of the water is removed from ethanol through distillation. Ethanol is flammable and contains a lot of energy which makes it useful as fuel for motor vehicles.Ethanol as a Motor Vehicle Fuel
Ethanol is a biofuel that has been blended with gasoline as a motor vehicle fuel since the 1980's or earlier when it was known as "gasohol". This was mainly a 90% gasoline / 10% ethanol mixture. This formula is still common, although the name gasohol is no longer commonly used.
 |
| Ethanol Gasoline Blend is Cheaper than Pure Gasoline Image Source: Dr. Penny Pincher |
If you look at the octane ratings at a fuel pump, you will find that the ethanol gasoline blend has a higher octane rating than pure gasoline. Many people assume that this means that ethanol gasoline has higher energy content than pure gasoline, but this is not true. The octane rating is an indication of controlled combustibility vs explosive combustibility of the fuel, not the energy content. The higher octane rating of ethanol indicates that it can be compressed to higher pressure before combustion than gasoline.
Gasoline actually has about 50% more energy content than pure ethanol. Another way to think about energy content: a gallon of pure ethanol has 66.7% of the energy content of a gallon of pure gasoline.
The commonly available ethanol blend fuel uses 90% gasoline and 10% ethanol. Vehicles that are "flex fuel" capable can use E85 which is 15% gasoline and 85% ethanol.
Advantages of Ethanol Gasoline Fuel
- Ethanol blends are cheaper than pure gasoline
- Produce less air pollution from burning ethanol gasoline blend vs pure gasoline
- Smaller carbon footprint than gasoline
- Growing plants to produce ethanol absorbs CO2 from the atmosphere
- However, ethanol is not carbon neutral since fuel is burned to plant and harvest the crops and transport ethanol
- Ethanol is a renewable fuel, gasoline is not
- The market for ethanol proves demand for alternate fuels
- Ethanol fuel blends reduce gas line freezing since ethanol can absorb water and remain a combustable fuel
Cons of Ethanol Gasoline Fuel
- Ethanol has less energy per gallon than gasoline- this means less miles per gallon
- Hard on small engines not designed to run on ethanol blends
- Use of crops to produce ethanol fuel drives up food prices
- Risk that drought could cause both food and fuel shortage
 |
| Gasoline Octane Rating- Lower than Ethanol Blend Image Source: Dr. Penny Pincher |
What is the difference between ethanol and biodiesel?
Ethanol is an alcohol that is usually blended with gasoline to produce fuel for engines that use gasoline. Biodiesel is fuel made from vegetable oil or animal fat that is used to replace diesel fuel in diesel engines.Both are renewable biofuels, but are used for different types of engines.
Is cheap ethanol gasoline a better deal than pure gasoline?
Most vehicles will get about 2% less miles per gallon using a 10% ethanol blend than with pure gasoline. However, the price of ethanol blend gasoline is less than pure gasoline. Is it a good deal? A check of local prices shows that pure gasoline is selling for $3.59 per gallon vs $3.49 per gallon for the 10% ethanol blend. The price for the ethanol blend is about 2.8% less than for pure gasoline. So at this price, the ethanol blend is a better deal than pure gasoline. You will get 2% reduction in gas mileage, but you pay 2.8% less.Penny Pinching Tips
- Ethanol fuel is a good deal- you will get slightly lower gas mileage with ethanol blend, but the lower cost more than offsets this difference
- Ethanol is a renewable biofuel and has a smaller carbon footprint than gasoline
No comments:
Post a Comment