The United States Environmental Protection Agency passed the Energy Policy Act in 1992. This act mandates that 75% of all light-duty vehicle (<8500 lbs.) purchases per year must be capable of running on alternative fuel. Texas HB 432 further requires that by September 2010, 50% of the university fleet must be of the alternative fuel variety. To be considered alternative fueled, a vehicle must use alternative fuels at least 80% of the time.
All of the fuels on the approved alternative fuels list are acceptable. However, due to the expense associated with training, providing necessary support equipment, and stocking various types of fuel, University Fleet Operations recommends departments limit their choice of fuel types. The three preferred alternative fuels are E85 and propane (LPG) for vehicles usually powered by gasoline, and biodiesel B20 for diesel trucks.
The information on alternative fuels below provides background and instruction for individual departments to reference when planning new vehicle purchases, preparing new vehicle purchase specifications, planning alternative fuels conversions for existing vehicles, and operating procedures for alternatively fueled vehicles.
E85 fuel is a renewable fuel that may be used in the future at the university. It contains 85% ethanol and 15% gasoline. Ethanol is non-toxic, water soluble, and biodegradable. It is produced by the fermentation of plant sugars, usually from corn or other grain products. Vehicles capable of using E85 fuel are called flex-fuel vehicles because a single fuel tank can hold any mixture of gasoline and ethanol fuel, up to 85% ethanol.
Ethanol (ethyl alcohol) is a renewable resource that is easy to manufacture and process. It can be blended with gasoline in varying amounts. Manufacturers have been producing E85 capable vehicles in large quantity, so availability of vehicles is quite good. Recent research has focused on making ethanol from a variety of sources other than just food crops. In fact, promising research at the university is underway to make ethanol from algae in very arid areas, making wastelands productive and not impacting food crop production.
The main disadvantage of E85 is the limited distribution/availability of the fuel (see E85 fueling station locator). The Austin area has very limited availability at this time. Other concerns relate to the large amount of arable land required for crops, as well as the energy and pollution balance of the whole cycle of ethanol production. Another disadvantage is that ethanol is somewhat corrosive and even at low concentrations may adversely affect older vehicles by eroding gaskets and other vehicle parts. University Fleet Operations is currently working with the City of Austin on a grant that will add E85 fuel to the main campus fuel station.
Liquefied Petroleum Gas (LPG)
The university uses propane, or liquefied petroleum gas (LPG). Vehicles capable of using propane fuel are required to use the fuel when it is available.
Because it is readily available (see propane outlet locator), LPG is the most commonly used alternative fuel in the United States. To liquefy the fuel, it is compressed to about 20 times standard atmospheric pressure and stored in heavy steel tanks. These tanks are much tougher than the typical sheet metal or plastic gasoline tanks found in most vehicles. Additionally, the tanks are built with an automatic shutoff valve that will seal the tank if one of the fuel lines develops a leak. For these reasons, LPG is generally considered safer than gasoline. In most places, it is also slightly less expensive in price than gasoline. Since LPG enters the engine as a vapor, it does not wash oil off cylinder walls or dilute the oil. When the engine is cold it doesn't deposit carbon particles or sulfuric acid in the oil. Thus, when an engine operates on propane, it usually enjoys a longer service life and reduced maintenance costs.
On a gallon-per-gallon basis, LPG is somewhat lower in energy content compared to gasoline. This difference produces the need for a slightly larger than average fuel tank to achieve the same driving range. The cost of required conversion equipment will increase the base price for the vehicle by about $2,500. LPG requires special care to dispense and should be done so only after training from the University Fleet Operations staff. LPG is available at both university fueling stations [link to Fueling Options for University Fleet Vehicles].
Biodiesel has been in use by the university since September 2001. B20 is composed of 80% standard petroleum diesel and 20% biodiesel. Biodiesel is made from renewable feedstock, such as vegetable oils and animal fats, through a simple refining process.
B20 can be stored and dispensed in exactly the same manner as 100% petroleum-based diesel fuel. Additionally, diesel-powered vehicles require no modification at all to run on B20. Thus any diesel-powered vehicle is, potentially, already an alternative-fueled vehicle. Since biodiesel is not a fossil fuel, it can cut greenhouse-gas emissions as well as ordinary pollutants (particularly soot) by displacing petroleum-based fuel. Because it requires no changes in hardware (vehicle or refueling) or retraining of mechanics and users, some studies have shown that it could be the most cost-effective way to meet clean-air requirements.
The main disadvantage of B20 is fuel cost. It generally cost more for biodiesel than for 100% petroleum-based diesel fuel. There are also concerns about cold weather performance. If the B20 has not been properly processed and/or properly blended it can congeal and clog fuel filters creating additional maintenance costs.
- EPA Green Vehicle Guide
- Energy Information Administration
- Drive Clean Across Texas
- TCEQ Smoking Vehicle Program
- Central Texas Clean Cities