WAY TO KNOWLEDGE...

                ALTERNATIVE FUELS

Ethanol

Ethanol is an alcohol-based fuel made by fermenting and distilling starch crops, such as corn. It can also be made from "cellulosic biomass" such as trees and grasses. The use of ethanol can reduce our dependence upon foreign oil and reduce greenhouse gas emissions.

E10 (gasohol)

E10 (also called “gasohol”) is a blend of 10% ethanol and 90% gasoline sold in many parts of the country. All auto manufacturers approve the use of blends of 10% ethanol or less in their gasoline vehicles. However, vehicles will typically go 3–4% fewer miles per gallon on E10 than on straight gasoline.

E85

E85, a blend of 85% ethanol and 15% gasoline, can be used in flexible fuel vehicles (FFVs), which are specially designed to run on gasoline, E85, or any mixture of the two. FFVs are offered by several vehicle manufacturers. To determine if your vehicle can use E85, consult your owner’s manual or check the inside of your car's fuel filler door for an identification sticker.
Cost. Cost varies regionally. It is cheaper than gasoline in some areas, such as the Midwest, and more expensive in others.
Availability. More than two thousand filling stations in the U.S. sell E85, and that number is increasing rapidly. Visit the Alternative Fueling Station Locator for locations of service stations selling E85.
Performance. No noticeable difference in vehicle performance when E85 is used.
MPG. FFVs operating on E85 usually experience a 25–30% drop in miles per gallon due to ethanol’s lower energy content.

Advantages	Disadvantages
Domestically produced, reducing use of imported petroleum Lower emissions of air pollutants More resistant to engine knock Added vehicle cost is very small	Can only be used in flex-fuel vehicles Lower energy content, resulting in fewer miles per gallon Limited availability Currently expensive to produce

Natural Gas

Natural gas, a fossil fuel comprised mostly of methane, is one of the cleanest burning alternative fuels. It can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG) to fuel cars and trucks.
Dedicated natural gas vehicles are designed to run on natural gas only, while dual-fuel or bi-fuel vehicles can also run on gasoline or diesel. Dual-fuel vehicles allow users to take advantage of the wide-spread availability of gasoline or diesel but use a cleaner, more economical alternative when natural gas is available. Since natural gas is stored in high-pressure fuel tanks, dual-fuel vehicles require two separate fueling systems, which take up passenger/cargo space.
Natural gas vehicles are not available on a large scale in the U.S.—only a few models are currently offered for sale. However, conventional gasoline and diesel vehicles can be retrofitted for CNG.

 

Advantages and Disadvantages of Natural Gas

Advantages	Disadvantages
Nearly 87% of U.S. natural gas used is domestically produced 60–90% less smog-producing pollutants 30–40% less greenhouse gas emissions Less expensive than gasoline	Limited vehicle availability Less readily available than gasoline and diesel Fewer miles on a tank of fuel

Propane: Liquefied Petroleum Gas (LPG)

Propane or liquefied petroleum gas (LPG) is a clean-burning fossil fuel that can be used to power internal combustion engines. LPG-fueled vehicles can produce significantly lower amounts of some harmful emissions and the greenhouse gas carbon dioxide (CO₂). LPG is usually less expensive than gasoline, it can be used without degrading vehicle performance, and most LPG used in U.S. comes from domestic sources.
The availability of LPG-fueled light-duty passenger vehicles is currently limited. A few light-duty vehicles—mostly larger trucks and vans—can be ordered from a dealer with a prep-ready engine package and converted to use propane. Existing conventional vehicles can also be converted for LPG use. Since propane is stored as a liquid in pressurized fuel tanks rated to 300 psi, LPG conversions consist of installing a separate fuel system if the vehicle will run on both conventional fuel and LPG or a replacement fuel system for LPG-only operation.

Advantages and Disadvantages of LPG

Advantages	Disadvantages
90% of propane used in U.S. comes from domestic sources Less expensive than gasoline Potentially lower toxic, carbon dioxide (CO2), carbon monoxide (CO), and nonmethane hydrocarbon (NMHC) emissions	Limited availability (a few large trucks and vans can be special ordered from manufacturers; other vehicles can be converted by certified installers) Less readily available than gasoline & diesel Fewer miles on a tank of fuel

Hydrogen

Hydrogen (H₂) is being aggressively explored as a fuel for passenger vehicles. It can be used in fuel cells to power electric motors or burned in internal combustion engines (ICEs).
It is an environmentally friendly fuel that has the potential to dramatically reduce our dependence on imported oil, but several significant challenges must be overcome before it can be widely used.

 

 

 

Benefits

Produced Domestically. Hydrogen can be produced domestically from several sources, reducing our dependence on petroleum imports.
Environmentally Friendly. Hydrogen produces no air pollutants or greenhouse gases when used in fuel cells; it produces only nitrogen oxides (NOx) when burned in ICEs.

 

 

 

Challenges

Fuel Cost & Availability. Hydrogen is currently expensive to produce and is only available at a handful of locations, mostly in California.
Vehicle Cost & Availability. Fuel cell vehicles are currently far too expensive for most consumers to afford, and they are only available to a few demonstration fleets.
Onboard Fuel Storage. Hydrogen contains much less energy than gasoline or diesel on a per-volume basis, making it difficult for hydrogen vehicles to go as far as gasoline vehicles between fillups—about 300 miles. Technology is improving, but the onboard hydrogen storage systems do not yet meet size, weight, and cost goals for commercialization.
Other challenges include fuel cell performance, customer acceptance, and hydrogen transport and bulk storage.