Douglas Tiffany

• B.S. and M.S. in Agricultural Economics
• Professor at University of Minnesota

Corn dried distiller’s grain with solubles (cDDGS) is a feeding ingredient for monogastric animals but with limited inclusion rate due to its imbalanced amino acids, high fiber content, and anti-nutritional compounds. Moreover, production of cDDGS is costly and energy intensive. This study investigated fungal fermentation of corn stillage mixing wi...

Fungal pre-treatment and fermentation could improve nutritional value of wet corn distillers’ grains and solubles (WDGS), soybean hull (SH), and their blend in swine and poultry diets, which can potentially increase revenues for corn-ethanol and soybean processing industries while reducing feed cost in swine and poultry production systems. This stu...

Corn wet distiller’s grain with solubles (WDGS) used as a feeding ingredient to monogastric animal diets is limited due to its imbalanced key amino acids, high fiber and potential existance of mycotoxins. Fermentation of WDGS by edible fungi has potential of upgrading the feedstock into nutritional and low-risk feeding ingredient for monogastric an...

Supply logistics systems for corn (Zea mays L.) stover and switchgrass (Panicum virgatum L.) with two collection methods, round bales and rectangular bales, are developed. A location in the US Midwest is assumed with corn grown on highly productive crop land and switchgrass grown on less productive land. Bales (15 % moisture wet basis) are stored a...

A life cycle assessment (LCA) study was conducted to understand and assess potential greenhouse gas (GHG) emissions reduction benefits of a biomass torrefaction business integrated with other industrial businesses for the use of the excess heat from the torrefaction off-gas volatiles and biocoal. A torrefaction plant processing 30.3 Mg h−1 of corn...

Throughout the past two decades, numerous studies characterized the greenhouse gas (GHG) emissions and net energy balance of corn ethanol production in the USA. A wide range of reported values resulted from differences in the vintage of the data used to evaluate the ethanol conversion technology and the agricultural practices of corn production, wh...

The consumption of wood pellets grew rapidly during the last decade. In this paper we compare the development of the production factors for wood pellet markets in Finland, Germany, Sweden, Norway and the US; we analyze how domestic market prices for pellet production factors as well as domestic market prices for pellets vary among the countries. Th...

Torrefaction technologies convert assorted biomass feedstocks into energy-concentrated, carbon neutral fuel that is economically transported and easily ground for blending with fossil coals at numerous power plants around the world without needs to retrofit. Utilization of torrefied biomass in conventional electric generating units may be an increa...

Dry-grind ethanol plants have the potential to reduce their operating costs and improve their net energy balances by using biomass as the source of process heat and electricity. We utilized ASPEN PLUS software to model various technology bundles of equipment, fuels and operating activities that are capable of supplying energy and satisfying emissio...

This paper presents an optimization study of the net present value of a biomass-to-ethanol supply chain in a 9-state region in the Midwestern United States. The study involves formulating and solving a mixed integer linear programming (MILP) problem. A biochemical technology is assumed for converting five types of agricultural residues into ethanol...

A mixed integer linear programming (MILP) problem formulation is proposed to optimize the net present value of a biomass-to-ethanol supply chain. Facility locations and capacities are determined simultaneously with biomass harvest and distribution. Sensitivity analysis and robustness are performed for a 9-state region of the United States case stud...

Short-rotation woody crops (SRWC) such as hybrid poplars are becoming increasingly competitive with agriculture on marginal land. The trees can be grown for energy and for traditional uses such as oriented strandboard. Using IMPLAN (Impact Analysis for Planning) software, we modeled the impacts of shifting land use from hay and pasture for cow-calf...

A life-cycle assessment (LCA) of corn ethanol was conducted to determine the reduction in the life-cycle greenhouse gas (GHG) emissions for corn ethanol compared to gasoline by integrating biomass fuels to replace fossil fuels (natural gas and grid electricity) in a U.S. Midwest dry-grind corn ethanol plant producing 0.19 hm3 y−1 of denatured ethan...

We evaluated the economics, energy inputs, and greenhouse gas (GHG) emissions for a proposed "field to facility" corn stover logistics system. The system included collection and transport by round bales to local storages within 3.2 km (2 mile) of the field during the fall harvest period followed by processing at the local storage sites throughout t...

A life-cycle assessment (LCA) of corn ethanol was conducted to determine the reduction in the life-cycle greenhouse gas (GHG) emissions of corn ethanol compared to gasoline by integrating biomass fuels in a 190 million liter (50 million gallon) per year dry-grind corn ethanol plant to replace fossil fuels (natural gas and grid electricity). The bio...

Considering the production goals for cellulosic and advanced biofuels in the Energy Independence and Security Act of 2007 (EISA), this study compares production costs and returns on invested capital for two current and three proposed ethanol technologies. Two methods use corn grain as the feedstock, and three use cellulosic feedstocks of corn stove...

We evaluated a corn stover logistics system that included collection and transport by round bales to local storages within 3.2 km (2 miles) of the field during the fall harvest period. This stage was followed by processing at the local storage sites throughout the year using mobile units which converted the bales to bulk material by tub-grinding an...

Biomass Integrated Gasification Combined Cycle (BIGCC) technology can be used to generate process heat and significant amounts of electricity at dry-grind ethanol facilities by utilizing the ethanol process co-products and other biomass sources. These systems can reduce fuel costs for ethanol plants, improve the renewable energy balance of dry-grin...

Dry-grind ethanol plants have the potential to reduce their operating costs and improve their net energy balances by using biomass as the source of process heat and electricity. We modeled various technology bundles of equipment, fuels, and operating activities that are capable of supplying energy and satisfying emissions requirements for dry-grind...

Several technology options are available that can help improve the sustainability of ethanol production from corn. Dry-grind ethanol process coproducts and other nearby biomass resources can be used to produce process heat and electricity at ethanol plants. These biomass fuels can reduce process energy costs, provide a consistent source of renewabl...

Transforming biomass into a product with bulk density of 240 kg/m3 (15 lb/ft3) would enhance logistics of truck transport to users throughout the year. We evaluated a system involving tub-grinding followed by roll-press compaction to increase the bulk density of biomass such as corn stover, corn cobs and native perennial grasses. Preliminary experi...

Biomass co-products from the dry-grind ethanol production process and/or corn stover are potential sources for the energy needed to operate the plant. The ethanol plant co-products alone contain sufficient energy to meet the electrical and thermal needs of the plant as well as to produce excess power that can be sold. Fuel characteristics of co-pro...

The utilization of short rotation woody crops (SRWC) to produce wood on marginal crop and pasture land could greatly enhance the production of wood for various uses in Minnesota with utilization for energy being of current interest. SRWC involves the more intensive application of inputs on more valuable land than naturally regenerated forests that...

For many years, U.S. policy initiatives and incentives have favored the production of ethanol from corn. The goals have been to increase corn prices and farmer income, enhance rural employment through encouragement of value-added businesses, increase energy security, and produce additives and/or fuels capable of reducing tailpipe pollutants and gre...

Current large scale biomass energy production systems including cellulosic ethanol, gasification, and pyrolysis facilities face significant technical and economic hurdles. Compared with these large scale systems, small distributed biomass energy production systems (DBEPS) are believed to offer advantages including lower capital costs, lower feedsto...

Biomass can provide electricity and process heat at dry-grind ethanol plants to both reduce costs and improve the net energy value of ethanol production. Distillers dried grains with solubles (DDGS), which are coproducts of ethanol production, can potentially be used for energy. Corn stover is another potential biomass energy source for ethanol pla...

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplie...

Production of biomass from native prairie species offers the opportunity to produce energy and chemicals while providing substantial ecological services in the Northern Great Plains. This paper analyzes the application of rapid pyrolysis to produce bio-oil, which has the potential for use as a low-grade fuel oil or as a source for extraction of val...

Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplie...

Replaced with revised version of paper 10/09/06.

The growth of wind power as an aspect of Minnesota’s portfolio of electricity has been propelled to its current level by policy initiatives at both the federal and state levels. Existing statutes establish requirements for further expansion of wind energy in this state in the years to come. Locally, production economics exert their influence as win...

Fuel and emission characteristics of co-products of the ethanol dry-grind process (distillers wet grains (DWG), concentrated distillers solubles (referred to as "syrup"), and distillers dried grains with solubles (DDGS)), and corn stover are evaluated. Biomass co-products from the dry-grind ethanol production process, particularly DDGS, are good so...

Biodiesel is a renewable fuel derived from vegetable oils or animal fats that can substitute for diesel fuel in engines or fuel oil in furnaces. Biodiesel has proven lubricity benefits at low blends and performs well as a substitute for petro-diesel. Blends of biodiesel reduce particulate matter (PM), volatile organic compounds (VOC), as well as ot...

Replaced with revised version of paper 08/24/04.

This study describes the movements of grain shipments from Minnesota to their final destinations. A sample of approximately 100 (20 percent) of Minnesota grain elevators reported their monthly grain shipments by mode to each of nine destinations from July 1999 to June 2000. The researchers used this data to project grain shipments from Minnesota an...

This study describes a portion of the grain production and movement patterns in Minnesota. 1999 levels of grain and oilseed production were identified as well as livestock populations in individual counties of the state. Animal scientists were consulted to ascribe typical consumption levels by the various livestock living in particular counties. A...

The objective of this project was to compare the cost of using neat biodiesel fuel and blends of biodiesel and petroleum diesel fuel to the cost of using other emission controls in underground mines. This report compares the life cycle costs of using filter emission controls and biodiesel and biodiesel blends for ten mine vehicles. It also gives th...

This article incorporates a political decision process into an urban land use model to predict the likely location of a public good. It fills an important gap in the literature by modeling the endogenous location of open space. The article compares open space decisions made under a majority rules voting scheme with welfare-improving criterion and f...

Economic analysis is being conducted by the Department of Applied Economics in support of Minnesota Alfalfa Producer`s development of alfalfa as a dedicated biomass feedstock for energy production. University Researchers have assisted in the development and implementation of inventory control systems and procedures. This report lists the tasks for...

Thesis (M.S. (Plan B))--University of Minnesota, 1977. Includes bibliographical references.