e85

Ethanol is a very attractive fuel from an end-use perspective because it has a high chemical octane number and a high
latent heat of vaporization. When an engine is optimized to take advantage of these fuel properties, both efficiency and
power can be increased through higher compression ratio, direct fuel injection, higher levels of boost, and a reduced need
for enrichment to mitigate knock or protect the engine and aftertreatment system from overheating.
The ASTM D5798 specification for high level ethanol blends, commonly called “E85,” underwent a major revision in
2011. The minimum ethanol content was revised downward from 68 vol% to 51 vol%, which combined with the use of
low octane blending streams such as natural gasoline introduces the possibility of a lower octane “E85” fuel. While this
fuel is suitable for current “ethanol tolerant” flex fuel vehicles, this study experimentally examines whether engines can
still be aggressively optimized for the resultant fuel from the revised ASTM D5798 specification.
The performance of six ethanol fuel blends, ranging from 51-85% ethanol, is compared to a premium-grade
certification gasoline (UTG-96) in a single-cylinder direct-injection (DI) engine with a compression ratio of 12.87:1 at
knock-prone engine conditions. UTG-96 (RON = 96.1), light straight run gasoline (LSRG, RON = 63.6), and n-heptane
(RON = 0) are used as the hydrocarbon blending streams for the ethanol-containing fuels in an effort to establish a broad
range of knock resistance for high ethanol fuels.
Results show that nearly all ethanol-containing fuels are more resistant to engine knock than UTG-96 (the only
exception being the ethanol blend with 49% n-heptane). This allows ethanol blends made with low octane number
hydrocarbons to be operated at significantly more advanced combustion phasing for higher efficiency, as well as at higher
engine loads.
While experimental results show that the octane number of the hydrocarbon blend stock does impact engine
performance, there remains a significant opportunity for engine optimization when considering even the lowest octane
fuels that are in compliance with the current revision of ASTM D5798 compared to premium-grade gasoline.

The market for E85�a fuel blend of 85 percent ethanol and 15 percent gasoline�is small
but growing rapidly. I use data for E85 sales at fueling stations in Minnesota to estimate
demand for E85 as a function of retail E85 and gasoline prices. I find that demand is
highly sensitive to price changes, with an own-price elasticity as high as -13 and a gasolineprice
elasticity as high as 16 at sample mean price levels. Demand is most sensitive to
price changes when the relative price of E85 is at an intermediate level, at which point
small price changes induce fuel switching by a large number of consumers. These results
are qualitatively consistent with a simple theoretical model of E85 demand, and the large
elasticities are in line with previous literature that estimates demand for fuels with nearperfect
substitutes. I estimate that roughly 40�50 percent of current E85 consumers are
fuel switchers, and that the average fuel-switching consumer is indifferent between the two
fuels when the ratio of gasoline to E85 prices is about 1.05�1.15. These ratios are somewhat
smaller than the ratio of gasoline to E85 fuel economy implied by government tests of
flex-fuel vehicles but consistent with reports on E85 fuel economy in the popular press.

A key objective of U.S. energy policy is to increase biofuel use by highway vehicles to 36 billion gallons per year by 2022. The Energy Independence and Security Act envisions that nearly all of this target will be met by gasohol (E10) or neat ethanol (E85). Since the market for blending ethanol with gasoline at 10% by volume will saturate at about 15 billion gallons, most of the ethanol will need to be sold in the form of E85 unless higher order blends are approved by automakers and the Environmental Protection Agency. The demand for E85 is likely to be very sensitive to the relative prices of E85 and gasoline and to the availability of E85 at retail outlets. The key objective of this study is to estimate the sensitivity of aggregate demand for E85 to the relative availability of E85 versus gasoline at retail outlets, as well as the sensitivity of E85’s market share to the prices of E85 and gasoline. Monthly data from the state of Minnesota for the period 1997 to 2008 are used to estimate a model of E85 choice by owners of flexible fuel vehicles. The results indicate that E85 availability at 10% to 20% of retail outlets might be sufficient to achieve a very substantial market share given an appropriate price advantage for E85.

One fundamental issue influencing the economic viability of the ethanol industry is consumers' demand responsiveness to both gasoline and ethanol price changes. This paper presents an alternative approach by estimating the geographic variation of price elasticity of demand for ethanol across the study area.

This study is a statistical analysis to estimate the significance of factors that influence the volume of E85 sales to the general public in Minnesota from 1997 to 2006.

The Alternative Fuels Data Center (AFDC) Station Locator identifies E-85 Fuel station locations across the country.

In 1997, eight E85 (85% ethanol; 15% gasoline) fuel pumps were installed at separate retail fuel stations in Minnesota to provide high-blend ethanol fuel to flexible fuel vehicle (FFV) owners. FFVs capable of utilizing gasoline, E85, or any mixture of the two, were beginning to be mass produced by vehicle manufacturers and distributed through fleet and retail sales nationwide. These state-level E85 efforts were part of larger federal and state policies and programs promoting the use of alternative transportation fuels to displace traditional gasoline and diesel fuel, which continue today. By the end of 2006, there were approximately 300 E85 fuel station
locations and over 125,000 FFVs in Minnesota. The amount of E85 fuel being utilized in the state was estimated at approximately 18 million gallons annually