ethanol

This report is an update of the original version, which was published in October 2008. This updated report includes results from the complete 16-vehicle fleet (the original report included only the first 13 vehicles tested) as well as corrections to minor errors identified in some of the originally reported data. Conclusions drawn from the complete dataset are nearly identical to those from the
original 13-vehicle fleet but with increased statistical confidence.

In summer 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate
the potential impacts of intermediate ethanol blends on legacy vehicles and other engines. The
purpose of the test program is to assess the viability of using intermediate blends as a contributor to meeting national goals in the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20—gasoline blended with 15% and 20% ethanol—on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials.

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.

This report identify the issues associated with intermediate ethanol blends with an emphasis on the end-use or
vehicle impacts of increased ethanol levels and compile a current and complete bibliography of key references on intermediate ethanol blends.

This paper estimates household preferences for ethanol as a gasoline substitute. I develop a theoretical
model linking the shape of the ethanol demand curve to the distribution of price ratios at which individual
households switch fuels. I estimate the model using data from many retail fueling stations. Demand
is price-sensitive with a mean elasticity of 2.5�3.5. I find that preferences are heterogeneous with many
households willing to pay a premium for ethanol. This reduces the simulated cost of an ethanol content
standard, since some households choose ethanol without large subsidies; simulated costs are still high
relative to likely environmental benefits.

Limited fuel availability is a critical factor in the marketability of new fuels. A survey of us households is used to estimate the value of fuel availability and its influence on choice of fuel for a fuel-flexible vehicle and the choice of a dedicated-fuel engine for a vehicle. The marginal value of availability decreases as the percent of stations offering a new fuel increases. For fuel-flexible vehicles the cost of lack of availability decreases from us $0.35/gallon at 1% to US $0.02/gallon when 50% of stations offer the fuel.

A presentation by Andrea Grant of Independent Fuel Terminal Operators Association.

A presentation by Bruce Heine of Magellan Midstream Partners to the 2006 Bioeconomy Conference held at Iowa State University.

This study quantifies the impact of increasing ethanol production on wholesale/retail gasoline prices employing pooled regional time-series data from January 1995 to March 2008. We find that the growth in ethanol production kept wholesale gasoline prices $0.14/gallon lower than would otherwise have been the case. The negative impact of ethanol on retail gasoline prices is found to vary considerably across regions. The Midwest region has the biggest impact at $0.28/gallon, while the Rocky Mountain region had the smallest impact at $0.07/gallon. The results also indicate that the ethanol-induced reduction in gasoline prices comes at the expense of refiners’ profits. We find a net welfare loss of $0.5 billion from the ethanol support policies in multiple markets.

The US is currently the world's largest ethanol producer. An increasing percentage is used as transportation fuel, but debates continue on its costs competitiveness and energy balance. In this study, technological development of ethanol production and resulting cost reductions are investigated by using the experience curve approach, scrutinizing costs of dry grind ethanol production over the timeframe 1980–2005. Cost reductions are differentiated between feedstock (corn) production and industrial (ethanol) processing. Corn production costs in the US have declined by 62% over 30 years, down to 100$2005/tonne in 2005, while corn production volumes almost doubled since 1975. A progress ratio (PR) of 0.55 is calculated indicating a 45% cost decline over each doubling in cumulative production. Higher corn yields and increasing farm sizes are the most important drivers behind this cost decline. Industrial processing costs of ethanol have declined by 45% since 1983, to below 130$2005/m3 in 2005 (excluding costs for corn and capital), equivalent to a PR of 0.87. Total ethanol production costs (including capital and net corn costs) have declined approximately 60% from 800$2005/m3 in the early 1980s, to 300$2005/m3 in 2005. Higher ethanol yields, lower energy use and the replacement of beverage alcohol-based production technologies have mostly contributed to this substantial cost decline. In addition, the average size of dry grind ethanol plants increased by 235% since 1990. For the future it is estimated that solely due to technological learning, production costs of ethanol may decline 28–44%, though this excludes effects of the current rising corn and fossil fuel costs. It is also concluded that experience curves are a valuable tool to describe both past and potential future cost reductions in US corn-based ethanol production.

The important key technologies required for the successful biological conversion of lignocellulosic biomass to ethanol have been extensively reviewed. The biological process of ethanol fuel production utilizing lignocellulose as substrate requires: (1) delignification to liberate cellulose and hemicellulose from their complex with lignin, (2) depolymerization of the carbohydrate polymers (cellulose and hemicellulose) to produce free sugars, and (3) fermentation of mixed hexose and pentose sugars to produce ethanol. The development of the feasible biological delignification process should be possible if lignin-degrading microorganisms, their ecophysiological requirements, and optimal bioreactor design are effectively coordinated. Some thermophilic anaerobes and recently-developed recombinant bacteria have advantageous features for direct microbial conversion of cellulose to ethanol, i.e. the simultaneous depolymerization of cellulosic carbohydrate polymers with ethanol production. The new fermentation technology converting xylose to ethanol needs also to be developed to make the overall conversion process more cost-effective. The bioconversion process of lignocellulosics to ethanol could be successfully developed and optimized by aggressively applying the related novel science and technologies to solve the known key problems of conversion process.