U.S. Department of Energy - Energy Efficiency and Renewable Energy
Alternative Fuels and Advanced Vehicles Data Center
Methodology
The State Assessment for Biomass Resources is a high-level screening application to show the current status and potential for biofuels on a state-level basis. The State Assessment for Biomass Resources has both a geographic and an analytic component. The geographic component is composed of two types of static maps for each state: Potential Production and Potential Use. The Potential Production maps show the biomass resource in the state by county as well as the existing and under construction biodiesel and ethanol production facilities. On the Potential Use maps, the Flexible Fuel Vehicle (FFV) registrations by county are shown as well as all biofuel refueling stations. The analytic component has three different calculation areas, by state: Current Situation, Potential Use and Potential Production. The Current Situation is static for each state and shows gasoline and diesel fuel use, infrastructure and biomass resource data. The Potential Use and Potential Production calculation areas are dynamic and are used to project various production and use scenarios based on user input. The Potential Use calculation area is displayed when the Potential Use map is shown, and the Potential Production calculation area is displayed when the Potential Production map is shown. This document focuses on the calculation areas and will outline their methodology, including the underlying data and assumptions.
Current Situation
Potential Use Calculations
Potential Production Calculations
- Ethanol from Cellulosic Biomass
- Percentage of Corn/Sorghum Used for Biofuels
- Ethanol from Corn and Sorghum
- Total Ethanol
- Biodiesel from Oil Seeds
Petroleum Displacement Result
Co-Product Production
References
Current Situation
As noted earlier, the Current Situation area is static for each state and provides baseline motor fuel use, flexible-fuel vehicles (FFVs), biofuels refueling infrastructure and production, and the total biomass resource. The following table describes the data sources for this area. Each item will be discussed in greater detail below.
Current Situation Data Summary
| Calculated Value | Units | Description | Data Sources | Year |
|---|---|---|---|---|
| Gasoline Use | million gallons | Total gasoline use in the state | Federal Highway Administration | 2004 |
| Diesel Use | million gallons | Total diesel use in the state | Federal Highway Administration | 2004 |
| E85 Stations | number of stations | Total E85 Stations in the state | Alternative Fuels Data Center (DOE) | June 2007 |
| Biodiesel Stations | number of stations | Total biodiesel stations in the state | Alternative Fuels Data Center (DOE) | June 2007 |
| Ethanol Plants | number of plants | Total ethanol plants in the state | Renewable Fuels Association and Ethanol Producer magazine | May 2007 |
| Total Ethanol Production Capacity | million gallons | Total ethanol production in the state | Renewable Fuels Association and Ethanol Producer magazine | May 2007 |
| Biodiesel Plants | number of plants | Total biodiesel plants in the state | National Biodiesel Board and Biodiesel magazine | May 2007 |
| Total Biodiesel Production Capacity | million gallons | Total biodiesel production in the state | National Biodiesel Board and Biodiesel magazine | May 2007 |
| Total Cellulosic Biomass | million dry metric tons | Total Biomass (wastes, forestry) potentially available for conversion to ethanol | NREL | 2005 |
| Total Crops Biomass | million dry metric tons | Total Crops potentially available for conversion to ethanol | USDA | 2006 |
Gasoline use is based on statistics from the Federal Highway Administration's Statistics for 2004. The total volume of gasoline sold in the state for highway use is used for this value. Diesel use is also obtained from this source. Diesel use is assumed to be equivalent to the special use fuel.
The number of FFVs is based on information obtained from R.L. Polk & Company. R.L. Polk & Company determined the number of FFVs based on state registration records. The data are from R.L. Polk & Company, Vehicles in Operation Database (April 2006 update). These data are presented in the maps, and are used in calculations.
The number of E85 and biodiesel stations was obtained for each state from the Alternative Fuels and Advanced Vehicles Data Center (AFDC). This value is dynamic and, especially in the case of E85, is growing rapidly. For this initial version of the State Assessment for Biomass Resources, the number of E85 and biodiesel stations and the stations shown on the map are current as of June 2007. Since this version of the State Assessment for Biomass Resources is not dynamic there may be some disagreement between the total alternative fuel stations shown in the AFDC and the number shown on the map.
The total number of ethanol plants and the total ethanol production in each state was determined from the Renewable Fuel Association (RFA) and Ethanol Producer Magazine (EPM) websites. The datasets were combined as there appeared to be plants in each dataset that weren't included in the other dataset. The combination of the two gives a more complete picture. Information on biodiesel was obtained from the National Biodiesel Board (PDF 358 KB) and Biodiesel Magazine's websites. Again, for the initial version of the State Assessment for Biomass Resources, the number of ethanol and biodiesel plants and the production volumes shown are static and current as of May 2007. (Download Adobe Reader)
The total cellulosic biomass value is the total dry metric tons of cellulosic biomass in the state, which is summed up by county. The total crop biomass value is the total dry metric tons of corn and sorghum in the state, also summed up by county. Total crop biomass was calculated using the following formula:
Variables
- Total Bushels Produced in 2006 (produced) - USDA, 2006
- Number of Pounds per Bushel (lb_conv) - 56 lb/bushel
- Moisture content of corn or sorghum (moist_cont) - 12% for sorghum, 15.5% for corn. Based on the Milbrandt 2005 study.
- Pound to metric ton conversion (metric_ton_conv) - 2205 lb/metric ton
- Metric tons of crop biomass - Calculated value
Calculation
- Total Crop Biomass = (produced)*(lb_conv)*(1-moist_cont)/metric_ton_conv
Oil seed crops were also gathered and used for biodiesel potential calculations. The following information was used in obtaining biomass data:
| Biomass Type | Description | Data Source |
|---|---|---|
| Oil Seed Crops | Canola, Cotton, Flax, Mustard, Peanut, Safflower, Soybean, Sunflower | USDA, 2006 |
| Grains | Corn and Sorghum | USDA, 2006 |
| Agricultural Residues | Corn, Wheat, Soybeans, Cotton, Sorghum, Barley, Oats, Rice, Rye Canola, Beans, Peas, Peanuts, Potatoes, Safflower, Sunflower, Sugarcane and Flaxseed | Milbrandt, 2005 |
| Forestry | Logging residues, pre-commercial thinning | USDA Forest Service Timber Product Output database for (2002) |
| Primary Mill Residues | Wood materials and bark from manufacturing plants | USDA Forest Service Timber Product Output database for (2002) |
| Secondary Mill Residues | Wood scraps and sawdust from woodworking shops | Milbrandt, 2005 |
| Urban Wood Waste | Municipal solid waste (MSW) wood, tree trimmings, construction/demolition wood | Milbrandt, 2005 |
Determination of the amount of biomass is based on the methodology outlined in Milbrandt (2005). Agricultural residues were estimated based on total crop production, crop to residue ratio, moisture as well as the amount of residue that should be left on the field to ensure proper soil protection. Forestry and primary mill residues were obtained from the USDA Forest Service's Timber Product Output database for (2002) while secondary mill residues and urban wood waste were determined from several sources as outlined in Milbrandt (2005).
On the maps, the biomass is grouped into three categories: Crops and Crop Residues, Forest and Primary Mill Residues, and Urban Wood and Secondary Mill Residues. Although the total tonnage is summed for this parameter, (i.e., total biomass), the appropriate conversion factor is used for each type of biomass to determine the amount of fuel produced.
Potential Use Calculations
In this section, the user can evaluate scenarios for deployment of both E85 and biodiesel blends. The calculation methodology for each fuel is presented below.
Percent Utilization of FFVs
This parameter evaluates the amount of E85 that could be used in the state based on the number of registered FFVs. The user selects the average percentage of time that all of the FFVs in the state use E85. The system then calculates the amount of E85 that would be required to meet this demand. The following is the basis for the calculation:
- User enters the % of time (0-100%) that all of the E85 vehicles in the state use E85 (Utilization of E85 Vehicles)
- System calculates how many gallons of E85 would be required to meet this demand.
- Variables
- % utilization in E85 vehicles (Perc_use) - User specified
- Number of FFVs (No_FFVs) - Total from Polk data for this state
- Average fuel used/LDV (Fuel_use) - 601 gallons/year, a constant based on the weighted fuel average of light-duty cars and trucks for 2005 from Tables 4.1 and 4.2 in the Transportation Energy Data Book (Davis and Diegel, 2007)
- E85 Conversion Factor (E85_fac) - 1.41, Ratio of LHV of Gasoline to that of E85 (Assumes that E85 is used all of the year - i.e., no E70)
- Million Gallons E85 Used (E85_Mgal) - Calculated value
- Calculation
- E85_Mgal = (No_FFVs)*(Perc_use)*(Fuel_use)*(E85_fac)/106
- Units - million gallons
Blend Biodiesel
This parameter evaluates the amount of biodiesel that would be required if all of the diesel vehicles in the state (light duty, medium duty and heavy duty) used an average biodiesel blend based on the total diesel used in the state. The user selects the average blend of biodiesel used in the state and the system calculates the amount of biodiesel that would be required to meet this demand.
- User selects the % of biodiesel blends used in diesel vehicles from a pull-down menu of B2, B5, B10, B15, B20, B40, B50 and B100 (The number after the B is the percentage of biodiesel in the blend. So B2 is 2% biodiesel blended with diesel.)
- System calculates how many gallons of biodiesel would be required to meet this demand.
- Variables
- % biodiesel blend (BD_Blend) - User specified
- Total diesel use in the state (Dsl_Use) - Gallons for Special Fuel from the Federal Highway Administration Statistics 2005
- Biodiesel conversion factor (BD_fac) - 1.10, Ratio of LHV of Diesel to Biodiesel to account for the lower energy content of biodiesel versus diesel
- Million Gallons of Biodiesel Used (BD_Mgal) - Calculated value
- Calculation
- BD_Mgal = (Dsl_Use)*(BD_Blend)*(BD_fac)/106
- Units - million gallons
Number of New Stations Required
In this section, the calculations are based on the number of new stations necessary to meet the demand(s) specified by the user for E85 and biodiesel in the previous section. The calculations subtract stations that already exist in the state from the total required, so only the number of new stations required to meet the user specified goal is displayed. Also, both ethanol and biodiesel calculations assume that a new station will dispense roughly 70,000 gallons of fuel per year based on an E85 Case Study by NREL (Johnson, 2007). The number of stations required will be rounded to the nearest whole number of stations.
E85 Stations
- Variables
- Annual E85 Use (E85_Mgal) - Obtained from Percent Utilization of FFVs above
- Average E85 Throughput (E85_Sales) - 70,000 gallons, a constant as described above
- Current E85 Stations in the State - (E85_Current) - Obtained from AFDC as described in Current Situation section
- New E85 Stations Required (E85_New) - Calculated value
- Calculation
- E85_New = ROUND((E85_Mgal)* 106/E85_Sales) - E85_Current
- Units - number of stations
Biodiesel Stations
- Variables
- Annual Biodiesel Use (BD_Mgal) - Obtained from Blend Biodiesel above
- Average Biodiesel Throughput (BD_Sales) - 70,000 gallons, a constant as described above
- Current Biodiesel Stations in the State - (BD_Current) - Obtained from AFDC as described in Current Situation section
- New Biodiesel Stations Required (BD_New) - Calculated value
- Calculation
- BD_New = ROUND((BD5_Mgal)* 106/BD_Sales) - BD_Current
- Units - number of stations
Potential Production Calculations
In this section, the user can evaluate scenarios for ethanol from corn, ethanol from biomass, and biodiesel from oil seeds; current and future technology cases may be analyzed. The calculation methodology is presented below.
Ethanol from Cellulosic Biomass
To calculate ethanol from biomass, the user selects the timeframe for the technology - 2005, 2009 and 2012 - and the system calculates the amount of ethanol that could be produced from all of the biomass in the state except corn, sorghum and oil seeds based on the projected state of technology at that time. In addition, the system assumes that agricultural residues are converted using biochemical conversion technologies while forestry residues and urban wood wastes would be converted using thermochemical conversion technologies (e.g., gasification followed by mixed alcohol production). The yields and feedstock scheme were taken from the Biomass Multi-Year Program Plan (MYPP) (U.S. DOE 2007).
The following table summarizes the yields for each year, technology and feedstock type (U.S. DOE 2007).
Projected Ethanol Yields from Biomass
| Feedstock | Conversion Technology | 2005 Technology Ethanol Yield (gal/dry metric ton) | 2009 Technology Ethanol Yield (gal/dry metric ton) | 2012 Technology Ethanol Yield (gal/dry metric ton) |
|---|---|---|---|---|
| Agricultural Residues | Biochemical Conversion | 65.3 | 74.3 | 89.8 |
| Forestry Residues and Urban Wood Waste | Thermochemical Conversion | 63.2 | 67.0 | 80.1 |
Users may select a technology time frame from a drop down menu: 2005, 2009 or 2012. The system defaults to 2005 timeframe and users may also select "none" as their timeframe to evaluate what the potential ethanol yield would be without including cellulosic biomass. After pressing Calculate, the system will calculate the yield based on the table above and the following calculation.
- Variables
- Agricultural residues (agric_tons) - Total metric tonnage of agricultural residues in the state
- Forestry residues (forest_tons) - Total metric tonnage of forestry residues in the state
- Primary mill residues (primary_tons) - Total metric tonnage of primary mill residues in the state
- Secondary mill residues (secondary_tons) - Total metric tonnage of secondary mill residues in the state
- Urban wood wastes (urban_tons) - Total metric tonnage of urban wood wastes in the state
- Ethanol yield from agricultural residues (AR_conv_2005, AR_conv_2009, or AR_conv_2012) - Ethanol yield from agricultural residues, constant value depending upon the technology timetable
- Ethanol yield from woody wastes (F_conv_2005, F_conv_2009, or F_conv_2012) - Ethanol yield from woody residues, constant value depending upon the technology timetable
- Total ethanol from biomass (EtOH_biomass) - Calculated value
- Calculation
- EtOH_biomass = (agric_tons)*(AR_conv_20##) + (forestry_tons+primary_tons+secondary_tons+urban_tons)*(F_conv_20##)
- Units - million gallons
Percentage of Corn/Sorghum Used for Biofuels
According to the Energy Independence and Security Act (EISA) of 2007, Title II, the limit of "conventional biofuels" in 2015 will be 15 billion gallons. Ethanol from corn starch is explicitly called out as a conventional biofuel in the Act, and for this study it is assumed that ethanol from sorghum will also be considered a conventional biofuel due to the average lifecycle greenhouse gas emissions for the conversion of sorghum to ethanol. As a result, 15 billion gallons was used as the baseline for limiting the corn/sorghum available for ethanol production in the future.
Conventional ethanol production from corn is a well-developed, mature technology based on either wet or dry mill processing. Most U.S. conventional ethanol plants are based on dry milling, and estimates of the conversion efficiency of the plants range from 2.65 to 2.8 gallons per bushel. For this analysis, a value of 2.7 gallons per bushel was used. This ethanol conversion value holds for sorghum, as well. Although corn ethanol is a mature process, efficiency improvements are possible. For this analysis, it was assumed that future technology could achieve a 15% increase in yield, based on improvements in corn yield, fiber conversion and/or other process improvements.
In addition, the total grain produced today in the United States was summed from the USDA (2006) as 11.05 billion bushels of corn and sorghum. While there is a potential for improvements in corn yield in the future, for this calculation we assume that the amount of corn produced in the United States in 2015 is the same as the amount of corn produced today, with no increased acreage or yield. These values were used as the basis for the maximum percentage of corn and sorghum available for ethanol production.
- Variables
- Limit of ethanol potential from grain (Limit_grain_etoh) - 15 billion gallons
- Grain yield (Grain_yield) - User specified:
- corn_conv_today (2.7 gallons/bushel) or
- corn_conv_today*corn_improvement (1.15*2.7 gallons/bushel)
- Total US Bushels Produced in 2006 (US_produced) - 11.05 billion bushels, USDA, 2006
- Limit of grain available for ethanol production (Grain_limit) - Calculated
- Calculation
- Grain_Limit = (Limit_grain_etoh/(corn_conv_today*corn_improvement))/ (US_produced) = 43%
- Units - percentage (%)
In addition, a National Corn Grower's (NCGA) study estimates the upper limit of ethanol that can be sustainably produced in the U.S. from corn at around 16 billion gallons per year based on projected corn yields and food/feed uses in 2015, which coincides with EISA limit for "conventional biofuels." (PDF 170 KB) Download Adobe Reader.
As a result, a user is allowed to enter any value into the application for the percentage of corn/sorghum used for biofuels; however, they will receive a warning if the value is above 40%.
Ethanol from Corn and Sorghum
Conventional ethanol production from corn is a well-developed, mature technology based on either wet or dry mill processing. Most U.S. conventional ethanol plants are based on dry milling, and estimates of the conversion efficiency of the plants range from 2.65 to 2.8 gallons per bushel. For this analysis, a value of 2.7 gallons per bushel was used. This ethanol conversion value holds for sorghum, as well. Although corn ethanol is a mature process, efficiency improvements are possible. For this analysis, it was assumed that future technology could achieve a 15% increase in yield, based on improvements in corn yield, fiber conversion and/or other process improvements.
Users may select none, current or future technology from a drop-down menu next to "Ethanol from Corn." The system defaults to the current timeframe and users may also select "none" as their timeframe to evaluate what the potential ethanol yield would be without including corn and sorghum. The calculation also takes into account the user entered value for the percentage of Corn/Sorghum used for biofuels discussed in section 5 above. The potential gallons produced will be calculated by the system based on the yields listed above and the following calculation:
- Variables
- Corn bushels (corn_bushels) - Total acreage planted in corn
- Sorghum bushels (SG_bushels) - Total acreage planted in sorghum
- Grain yield (Grain_yield) - User specified:
- corn_conv_today (2.7 gallons/bushel) or
- corn_conv_today*corn_improvement (1.15*2.7 gallons/bushel)
- User limit of corn and sorghum available for fuel production (User_limit) - User specified as described in Percentage of Corn/Sorghum Used for Biofuels above.
- Total ethanol potential from grain (Total_grain_etoh) - Calculated value
- Calculation
- Total_grain_etoh = User_limit * ((corn_bushels + SG_bushels)*(Grain_yield))
- Units - million gallons
Total Ethanol
The total ethanol potential production in the state is summed by adding the calculated cellulosic ethanol potential to the calculated corn and sorghum potential.
- Variables
- Total ethanol from biomass (EtOH_biomass) - Obtained from Ethanol from Cellulosic Biomass above.
- Total ethanol potential from grain (Total_grain_etoh) - Obtained from Percentage of Corn/Sorghum Used for Biofuels above.
- Total ethanol potential (Total_etoh) - Calculated value
- Calculation
- Total_etoh = EtOH_biomass + Total_grain_etoh
- Units - million gallons
Biodiesel from Oil Seeds
Biodiesel production is assumed to be from oilseed crops only. It could be produced from other sources such as biomass pyrolysis oils, but for this screening application only vegetable oils (canola, cotton, flax, mustard, peanut, safflower, soybean, sunflower) are assumed for feedstocks.
The production of oilseeds for 2006 was obtained from the USDA. Conversion factors from acres of oil seed to biodiesel were obtained from a 2004 NREL study (Tyson et al. 2004) for each type of oil seed except flax. The conversion of flax to biodiesel was obtained from CroplandBiodiesel.com. The following table summarizes the conversion factors used.
Biodiesel Yield from Oil Seed Crops
| Oil Seed Crop | Biodiesel Yield (gal/acre of oilseed) |
|---|---|
| Canola | 71 |
| Cotton | 23 |
| Flax | 51 |
| Mustard | 48 |
| Peanut | 98 |
| Safflower | 44 |
| Soybean | 56 |
| Sunflower | 70 |
All of the factors are for current yields of oil from the oilseeds as well as current technology. Although biodiesel is a commercial technology, there may be improvements in the technology and/or oil yields. In fact, Tyson et. al. (2004) projects an improvement of 25% of oil from oil seeds in the future. For this application, the user can select current technology and the system will calculate the yield of biodiesel based on the amount of acreage planted in specific oil seeds and the conversion factors in the table above. For future technology, all oil seed yields are increased by 25%.
The following outlines the specific calculation used:
- Variables
- Acres of canola oil seeds (canola_acres) - Acres of canola under cultivation in the state
- Acres of cotton (cotton_acres) - Acres of cotton under cultivation in the state
- Acres of flaxseed (flax_acres) - Acres of flaxseed under cultivation in the state
- Acres of mustard seed (mustard_acres) - Acres of mustard seed under cultivation in the state
- Acres of peanuts (peanut_acres) - Acres of peanuts under cultivation in the state
- Acres of safflower (saff_acres) - Acres of safflower under cultivation in the state
- Acres of soybean (soy_acres) - Acres of soybeans under cultivation in the state
- Acres of sunflower (sun_acres) - Acres of sunflower under cultivation in the state
- Yield from canola (canola_yield) - Yield of biodiesel from an acre of canola, constant, 71 gallons/acre
- Yield from cotton (cotton_yield) - Yield of biodiesel from an acre of cotton, constant, 23 gallons/acre
- Yield from flaxseed (flax_yield) - Yield of biodiesel from an acre of flaxseed, constant, 51 gallons/acre
- Yield from mustard (mustard_yield) - Yield of biodiesel from an acre of mustard, constant 48 gallons/acre
- Yield from peanuts (peanut_yield) - Yield of biodiesel from an acre of peanuts, constant, 98 gallons/acre
- Yield from safflower (saff_yield) - Yield of biodiesel from an acre of safflower, 44 gallons/acre
- Yield from soybeans (soy_yield) - Yield of biodiesel from an acre of soybeans, 56 gallons/acre
- Yield from sunflowers (sun_yield) - Yield of biodiesel from an acre of sunflowers, 70 gallons/acre
- Potential biodiesel (Pot_BD) - Calculated value
- Calculation
- Pot_BD = (canola_acres)*(canola_yield) + (cotton_acres)*(cotton_yield) + (flax_acres)*(flax_yield) + (mustard_acres)*(mustard_yield) + (peanut_acres)*(peanut_yield) + (saff_acres)*(saff_yield) + (soy_acres)*(soy_yield) + (sun_acres)*(sun_yield)
- Units - million gallons
Petroleum Displacement Result
The amount of conventional fuel that can be displaced by biofuels is calculated as the conventional fuel equivalent of the total ethanol or biodiesel produced divided by the amount of gasoline or diesel (respectively) that is currently in use in the state. The % gasoline use replaced by ethanol and % diesel use replaced by biodiesel values are recalculated after the Calculate button is clicked.
% Gasoline Use Replaced by Ethanol
This calculation determines the amount of gasoline that can be displaced by potential ethanol in the state.
- Variables
- Total ethanol potential (Total_etoh) - Obtained from Total Ethanol above.
- E85 Conversion Factor (Ethanol_fac) - 1.52, Ratio of lower heating value (LHV) of gasoline to that of ethanol to account for the lower energy content of ethanol versus gasoline
- Gasoline use (Gasoline_use) in gallons - Total gasoline use in the state from the Federal Highway Administration, 2004
- Percentage gasoline use replaced by ethanol (Perc_gas_use) - Calculated value
- Calculation
- Perc_gas_use = Total_etoh/(Ethanol_fac*Gasoline_use)
- Units - percent (%)
% Diesel Use Replaced by Biodiesel
This calculation determines the amount of diesel that can be displaced by potential biodiesel in the state.
- Variables
- Potential biodiesel (Pot_BD) - Obtained from Biodiesel from Oil Seeds above.
- Biodiesel conversion factor (BD_fac) - 1.10, Ratio of LHV of diesel to biodiesel to account for the lower energy content of biodiesel versus diesel
- Diesel use (Diesel_use) in gallons - Total diesel use in the state from the Federal Highway Administration, 2004 and 2005
- Percentage diesel use replaced by biodiesel (Perc_diesel_use) - Calculated value
- Calculation
- Perc_diesel_use = Pot_BD/(BD_fac*Diesel_use)
- Units - percent (%)
Co-Product Production
The production of biofuels also produces several co-products including animal feed (e.g., Distiller Dried Grain) from corn ethanol; electricity from biochemical biomass ethanol; mixed alcohols from thermochemical biomass ethanol; and glycerol from biodiesel production. For this analysis, the amount of two co-products, animal feed and electricity, are estimated.
Electricity
Electricity is a major co-product of the biochemical conversion of biomass into ethanol. The following table projects the electricity available for export based on the technology timeline (i.e., 2005, 2009 or 2012) selected for the "Ethanol from Biomass" parameter.
Electricity for Export from Biomass Ethanol Technology
| Technology Timeframe | Electricity for Export (kWh/gal ethanol) |
|---|---|
| 2005 | 4.4 |
| 2009 | 3.5 |
| 2012 | 2.4 |
Values in the table were obtained from Table B-4 of the Biomass MYPP (U.S. DOE 2007).
- Variables
- Ethanol from biomass (EtOH_biomass) calculated in Ethanol from Cellulosic Biomass
- Electricity for export (elec_2005, elec_2009, elec_2012 ) - Constant (kWh/gal ethanol) depending on the technology timeframe
- Electricity produced (Elec)
- Calculation
- Elec = (EtOH_biomass)*(elec_20##)/1000 in MWh
- Units - GWh = gigawatt hour = 1 x 109 Wh = 1 x 106 kWh
Animal Feed
The amount of animal feed produced from the corn ethanol process is estimated at 6.8 lb/gallon of ethanol produced (Graboski, 2002). In the future, it is estimated that the protein yield of this co-product will remain the same, but the overall mass will decrease as the fiber, currently 9-10% of the co-product, will be converted to ethanol. Animal feed is a very valuable co-product and so it is likely that improvements in the ethanol process will only affect the 9% that is fiber. In fact, animal feed is sold on its protein content, which will be unaffected by process improvements such as fiber conversion. Thus, future yields of animal feed are assumed to decrease by 10% to 6.12 lb/gal ethanol.
The following is the calculation of animal feed from corn ethanol.
- Variables
- Corn ethanol (Total_grain_etoh) - Calculated in Ethanol from Corn and Sorghum
- Animal feed yield (DDG_yield or DDG_yield_future) - Constant value 6.8 lb/gal ethanol or 6.12 lb/gal ethanol for the future case
- Animal feed produced (Feed)
- Calculation
- Feed = (Total_grain_etoh)*(DDG_yield or DDG_yield_future) (in millions of pounds)
- Units - thousand metric tons
References
Davis, S. and S. Diegel. 2007. "Transportation Energy Data Book: Edition 26," ORNL-6978 (Edition 26 of ORNL-5198).
Graboski, M. 2002. "Fossil Energy Use in Corn Ethanol Production," Prepared for the National Corn Growers Association (PDF 343 KB) Download Adobe Reader.
Johnson, C. 2007 "E85 Retail Business Case: When and Why to Sell E85." NREL Report, PR-540-42239.
Milbrandt, A. 2005. "A Geographic Perspective on the Current Biomass Resource Availability in the United States," NREL/TP-560-39181, December.
Tyson, K.S., J. Bozell, R. Wallace, E. Petersen, L. Moens. "Biomass Oil Analysis: Research Needs and Recommendations," NREL Technical Report, NREL/TP-510-34796, June.
U.S. DOE. 2007. "Biomass Multi-Year Program Plan," Office of the Biomass Program, Energy Efficiency and Renewable Energy, August.