Other Alternative Fuels
Ethanol is a renewable fuel that is produced domestically with plant materials, or biomass. A small percentage of Ethanol is found in nearly half of all gasoline and is considered an alternative fuel with higher concentrations, the most common being E85 (85% ethanol, 15% gasoline) which may be used in a flex fuel vehicle. While the fuel efficiency is a little less than gasoline, E85 typically costs less and has environmental and health benefits including fewer evaporative emissions and it reduces carbon monoxide and carcinogen (e.g. benzene) emissions.
Ethanol has received some scrutiny because it does emit acetaldehyde, a toxic pollutant and the sustainability of its production has been questioned. However, the peer-reviewed Greenhouse gases, Regulated Emissions and Energy use in Transportation (GREET) model has determined that ethanol outperforms conventional fuel—0.78 million British thermal units (Btu) of fossil energy are consumed to make enough ethanol to deliver 1 million Btus whereas 1.23 million Btus of fossil energy are required for the amount of gasoline to deliver 1 million Btus. For more information, click here.
Hydrogen is the most abundant element in the universe, but the elemental form of hydrogen is rare on earth, most of it is captured in water, hydrocarbons and other organic matter. Therefore, it needs to be produced and stored in a form that can later be used to created electricity to power fuel cell vehicles. Hydrogen may be produced in a variety of ways including renewable electrolysis, gasification, or photobiological processes and is transported as a liquid in tankers (e.g. rail, ship, barge) or as a gas via pipeline or in high-pressure tankers. Hydrogen has great potential for being a near-zero emission solution because once the hydrogen is produced, which it may be with renewable resources, it generates power with zero emissions. Click here for more information.
Natural gas is produced primarily in the US as compressed natural gas (CNG) or liquefied natural gas (LNG) and is used in both light-duty and heavy duty vehicles. The majority of natural gas is formed from heat and pressure on organic material over millions of years—it is a fossil fuel but it burns cleaner than petroleum based fuels. Once the gas is extracted, it must be processed to separate it from residual liquids and solids and then further refinement to meet specified requirements. With an extensive distribution network already in place, 300,000 miles of pipelines, the delivery of natural gas is fast and economic.
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Propane gas or liquefied petroleum gas (LPG) is a byproduct of natural gas processing and petroleum refining. Propane has one of the highest energy densities of the clean fuels used for transportation and is one of the safest with the lowest flammability range and a storage tank 20 times more puncture resistant than a gasoline tank.
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