ENERGETIC AND ECONOMIC FEASIBILITY
ASSOCIATED
WITH THE PRODUCTION,
PROCESSING
AND CONVERSION
OF BEEF TALLOW TO DIESEL FUEL
Richard G. Nelson and Mark D. S&rock
Kansas State University
Manhattan, KS 66506
Abstract
This study investigates the energetic and economic feasibility associated with the conversion of beef tallow
to a substitute diesel fuel. Three separate starting points within the tallow production and processing were
considered: (I) transesterification, (2) rendering plant operations and (3) animal growth life cycle.
Energy-profit ratios and economic feasibilities (cost per gallon) were determined for the conversion of
tallow subject to the transesterification process alone, the rendering plant operation and transesterification
of the tallow, and the growth and maintenance of the beef animal from conception through rendering and
transesterification. Energy-profit ratios were, respectively, 3.07, 1.36 and 0.49.
Three separate sensitivity analyses were performed to determine the effect of feedstock cost, by-product
(glycerol) credit and electrical and natural gas rates on the cost per gallon transesterified. Cost of
production data was determined for both a 3 and 30 million gallon per year continuous-flow
transesterification unit with capital equipment costs of $1.00 and $0.50 per gallon, respectively.
Feedstock cost had the greatest impact on the cost per gallon followed by by-product credit and utility
rates. Transesterification production costs ranged from $0.92 per gallon to $1.67 per gallon depending
upon feedstock cost, by-product credit, utility rates and unit size. Production costs averaged $0.174 per
gallon higher when tallow processing at the rendering plant was considered.
An assessmentof the quantity of tallow generated both nationally and within the beef processing industry
was performed. The seven largest beef cattle slaughtering statesgenerate nearly three and one-half billion
pounds of rendered tallow each year.
848
Introduction
In recent years, there has been an increased interest in alternate transportation
economic, and environmental
impacts related to the continued use of petroleum
fuels due to energetic,
as a fuel source.
Biodiesel, a diesel fuel substitute derived from vegetable oils and animal fats, has been demonstrated in
unmodified diesel engines, Comparisons between biodiesel and fossil-based diesel have shown biodiesel
to be effective in reducing exhaust emissions of carbon monoxide, hydrocarbons, particulates and sulfur
(Ayres 1992).
Production
of an agriculturally-derived
substitute diesel fuel has the potential to partially ease our
dependence on fossil-based fuel sources, lessen the debt load associated with imported petroleum, and
alleviate some of the environmental
concerns affiliated with petroleum combustion.
The current tallow market appears to favor biodiesel commercialization
for two reasons. First, dietary
preferences of the nation are changing toward leaner diets and unsaturated fats which will place a
downward trend on the price of tallow.
Secondly, the properties that make tallow less attractive for
fat-conscious consumers (i.e. degree of saturation) are not of great concern when used as a fuel source.
Objectives
The primary objective of this study was to assess the energetic and economic
diesel fuel substitute from beef tallow. Specific objectives were to:
feasibility
(1) Determine the quantity of edible and inedible tallow generated on a national
quantity generated from beef processors/meat packing plants
(2) Determine
tallow
the energetics associated with production
(3) Determine
the economic
feasibility
Rationale
of producing
of producing
a
basis and the
and processing of biodiesel
from beef
and processing beef tallow into biodiesel.
and Justification
Diesel fuel accounts for over 20% of the transportation energy used in this country and has experienced
the second largest growth rate among fuel types since 1982 (Davis and Morris 1992). Imports of
petroleum,which result in a $50 billion peryearnegativepetroleumtradebalance,haverisenat anannual
rate of 5.2% in the same time period (Davis and Morris 1992). Since 1982, domestic oil production has
decreased at an average annual rate of 2%. The energy-profit ratio, defined as the ratio of energy
recovered and provided to society to that required to explore, produce and transport U.S. petroleum, has
decreased from 50 in the 1950’s to between 5 and 1 today and is projected to be equal to or less than 1
by 2005 (Gever et al. 1986).
849
In addition, an increasing concern surrounds air pollution
resulting from fossil-fuel combustion.
In
October 1993, the Environmental
Protection Agency will enact legislation requiring on-highway diesel to
have a sulfur content of no more than O.OS%, a maximum of 35% aromatics, and a cetane of at least 40
(National Petroleum News 1991). These and more stringent regulations that may follow will encourage
the diesel fuel industry to consider alternative fuels.
Resource
Assessment
The majority of tallow (edible & inedible) in this country is currently generated by the meat packing,
poultry and edible/inedible
rendering industries.
Animal fats are currently most often used as a
supplement for animal feed (62.4% market share), followed by use in fatty acids (22.4%), soap (10.4%),
lubricants (3.4%j and other uses (1.4%) (Bisplinghoff
1992).
National statistics gathered by four private and government organizations show an average generation of
1.205 and 5.089 billion pounds of edible and inedible tallow, respectively, in 1990 (American Meat
Institute 1992; Bisplinghoff
1992; U. S. Department of Agriculture 1992; U.S. Depattment of Commerce
1991). A survey of Midwestern beef processors revealed that the percentage of tallow generated by
weight per head of cattle slaughtered varied from 5.4 to 8.0% for inedible tallow to 5.0 to 8.7% for edible
tallow (Nelson 1992). The seven largest cattle slaughtering states produce over 50% of the nation’s edible
and inedible beef tallow (USDA 1990).
Major beef processors in Southwest Kansas generate an average of over 3 million pounds of edible and
inedible tallow per day, which, if transesterified, could produce nearly 400,000 gallons of biodiesel. The
beef processing industry in Kansas has the tallow resource to displace over 25% of the state’s distillate
fuel consumption requirements.
Energetic
Feasibility
The feasibility of producing biodiesel from tallow involves, in part, comparing the quantity of energy
required to transform tallow into a diesel fuel substitute to that contained in the fuel. For tallow-based
biodiesel to be feasible from an energetics standpoint, a net energy gain must be realized with the
transformation
process; i.e., the process must consume less energy than is actually contained in the fuel
itself. Energetic feasibility is an important component leading to economic feasibility.
Energetic analysis is used to determine the amount of energy (thermal basis) needed to produce one gallon
of methyl tallowate. In this study, energetics are presented in the form of an energy-profit ratio (EPR);
i.e., the amount of thermal energy contained in the fuel divided by the amount of thermal energy required
to transform tallow to a fuel source. An EPR greater than one indicates a favorable energy conversion
The thermal energy contained in one gallon
while an EPR less than one indicates an energetic liability.
of methyl tallowate is based on a value of 126,684 Btu (Sims 1985).
Determination
of the energy-profit ratio associated with converting tallow to a substitute diesel fuel is a
function of the point at which the energetic feasibility analysis begins. Table 1 lists the three starting
points considered in both the energetic and economic analysis and feedstock condition at the start of each
analysis. Ener,gy-profit ratios are presented for each of the three starting points.
850
TABLE
Energetic
and Economic
Tallow
Feasibility
Production
Starting
1
Analysis
Starting
and Transformation
Point of Analysis
Case #l
Transesterification
Case #2
Rendering
Case #3
Animal
Process
Plant
Growth
Operations
Life Cycle
Points Associated
Process
Feedstock
Rendered
Animal
with the
Considered
Tallow
Fat
Fossil-fuel inputs for livestock
feed and transportation
The first energetic analysis (case #l) is concerned with only the transesterification
process. It assumes
that the rendered tallow is available as a by-product of beef production.
The second energetic analysis
(case #2) is concerned with the amount of energy required to process tallow at the rendering plant and
transesterify the tallow. The third energetic analysis (case #3) deals with the growth and maintenance of
the beef animal from conception through rendering and transesterification.
The amount of energy needed to transform tallow to a fuel source involves accounting for direct and
embodied energy inputs within each of the energetic analyses. Direct energy inputs are the electrical and
thermal energies (natural gas, diesel, etc.) required to operate the transesterification unit, process the tallow
at the rendering plant and produce, process, harvest and transport the feed ration components and beef
cattle. Embodied energy inputs are those energies required to manufacture, distribute and/or process
machinery and equipment such as the transesterification
unit, tractors, combines, and irrigation systems
as well as the esterification process reaction chemicals, fertilizers, pesticides and seeds.
Table 2 presents values and references of direct and embodied energies of the materials,
fuels used in each of the three cases considered in the energetic feasibility analysis.
Case #l : Tallow
Transesterification
chemicals
and
Energetics
Calculation of the energy-profit ratio as it relates to the transesterification
of beef tallow into a methyl
ester is based on the continuous-flow
process developed by GraTech, Inc. (1993).
Direct energy
requirements per gallon of transesterified tallow are 1,114 Btu electrical (thermal basis) and 25,45 1 Btu
thermal based on electrical and thermal requirements of 0.1173 kW and 16 pounds of 150 psig saturated
steam per gallon, respectively.
Calculations incorporated a power plant efficiency of 35% and a boiler
efficiency of 75%. A significant portion of the thermal energy is used to recover the methanol, which is
supplied in excess in order to drive the esterification to completion.
Embodied energies for the methanol and sodium hydroxide were calculated as 13,850 Btu and 773 Btu
per gallon of tallow transesterified, respectively.
In addition, embodied energy for production of the
transrsterification
unit was calculated per gallon of methyl tallowate and was determined to be negligible
for both the 3 million and 30 million gallon per year units.
The energy-profit
ratio associated
determined to be 3.07.
with the tmnsesterification
851
of beef tallow to methyl
tallowate
was
TABLE
Direct
and Embodied
Energies
2
for Materials,
Material/Chemical/Fuel
Chemicals
and Fuels
Enerav
Content
Reference
218E+06
98E+06
Btu/ton
Btu/ton
W,(9)
Materials:
Aluminum
Brass
Cast Iron
PVC
28E+06 Btu/ton
75E+06 Btu/ton
(3)
(3)9(g)
(4)O)
Rubber
Steel
58E+06
22E+06
Btu/ton
Btu/ton
wm
(2)
Btu/lb
(4)
(4)
Fertilizers/Chemicals:
Nitrogen
Phosphate
32,973
6,887 Btu/ib
Potassium
Pesticides
Sodium Hydroxide
Methanol
specific
5,510 Btu/lb
by pesticide
(4)
(4)
(3)
(3)
10,305 Btu/lb
18,466 BtuAb
Fuels:
Diesel
128,000
32,730
22,700
126,684
(direct)
Diesel (embodied)
Lubricating
Oil (embodied)
Methyl Tallowate
Btu/gal
Btu/gal
Btu/gal
Btu/gal
References:
(1) Adler 1986; (2) AISI 1993; (3) Boustead and Hancock
(4) Fluck 1992; (5) Fluck 1993; (6) OTA 1992; (7) Pimentel
1980;
(1)
(7)
(5)
(‘3)
1979;
(8) Sims 1985; (9) SPI 1992
Case #2: Rendering
Plant
Energetics
Rendering plant energetics quantify the electricity and natural gas used to render the tallow. Processing
operations involve crushing and/or grinding, cooking, pressing, and centrifuging the tallow before it is
acceptable for transesterifkation
purposes.
A major Midwestern meat packer (Cargill 1993) provided electricity and natural gas cost data. Electrical
costs were SO.054 per gallon of tallow and natural gas costs were $0.12 per gallon based on energy prices
of $0.06 per kW-h and $2.80 per MCF. Thus, the thermal energy equivalent required per gallon of tallow
processed is 5 1,633 Btu using a power plant effkiency of 35%. Embodied energies for process equipment
were not considered in this analysis.
The energy-profit ratio is equal to 1.36 when considering the electrical and thermal energies in this process
as well as the energy required in the transesterification
process.
852
Case #3: Animal
Growth
Life Cycle
Energetics
Energetics associated with the growth and maintenance of the beef animal from conception through
transesterification
involves accounting for the energy required to produce, process and transport feed ration
components and the energy required to transport the animal from the pasture, to the feedlot and rendering
plant. Energy data presented in this study are only applicable to the state of Kansas. Typical feed ration
components and quantities consumed by cattle and their associated breeding stock in Kansas throughout
their lifetimes are 1.24 tons of irrigated corn, 0.57 tons of dryland grain sorghum, 0.04 tons of soybean
meal, 0.67 tons of irrigated alfalfa and 1.59 tons of sorghum silage (Kuhl 1992). Crop production energy
data for corn, alfalfa and silage were derived for the western one-third of the state while energies
calculated for soybean and gmin sorghum production were state averages.
Production
fertilizers,
performed
of each feed ration component requires the use of machinery, fuel, lubricants, irrigation,
pesticides, seeds, and transportation.
Drying of feed ration components is generally not
in Kansas and was therefore not considered in this analysis.
Both direct and embodied energies were determined, where appropriate, for each of these crop production
inputs.
For all feed ration components, the energy expended per ton of feed ration produced was
determined by dividing the energy use per acre (Btu/acre) by’the crop yield (bushels/acre).
The total amount of energy required to raise and maintain the beef animal from conception through
slaughter is the sum of the energies required to produce, harvest, process and transport the quantity of each
feed ration component consumed, the energy for feedlot maintenance and the energy to transport the
animal to the feedlot and beef processor.
Because tallow is just one of several marketable products produced from the beef animal, only a portion
of the energy needed to grow the beef animal was assigned to the tallow. Proportions were calculated on
the basis of the mass of marketable product. That is, about 63% of live animal mass is marketed (Kuhl
1993), and approximately
12.7% of live animal mass is marketed as tallow (Cargiil 1993). Thus, 20.3%
of the total marketed mass is tallow, so the same percentage of the animal production energy was assigned
to the tallow. It should be noted that a considerably lower energy charge would have been assigned to
the tallow had the proportioning
been based on dollars of market value.
Machinery
A simplified method of estimating the embodied energy in farm machinery was developed, based on the
hypotheses that the energy needed to manufacture the machine and its repairs should have a strong
Clark and Johnson (1975) estimated
correlation to the direct energy consumed by the machine.
manufacturing and repair energy based on monetary cost and a BTU/$ multiplier.
The resulting ratio of
indirect energy/direct energy was about 0.46.
An alternative
approach,that of amortizing the massof tractors,combines, and tillage
tools over their
useful lives, produced a ratio of 0.28. For this study, it was estimated the amount of energy needed to
manufacture
a machine and its repair to be equal to 0.35 times the direct energy consumed by the
machine. Calculation of the indirect to direct energy ratio applied to irrigated corn production
data supplied by Bowers (1992) produced a value of 0.36.
853
machinery
FuelslLubrican
ts
The quantity of fuel (diesel) and lubricants used for tillage, planting and harvesting each feed ration
component was derived from cost production data ($/acre) for selected Kansas crops (Langemeier 1991).
Diesel fuel consumption (gallons/acre) was determined by dividing the cost per acre by the average cost
of on-farm diesel.
Direct and embodied energies of diesel fuel and embodied energy of lubricants expended per acre
(BtuIacre) were calculated as the gallons of each consumed per acre multiplied by the direct or embodied
energy content. Total fuel and lubricant energy expended per acre is the sum of the direct energy of diesel
fuel and embodied energies of diesel fuel and lubricants.
lrriga tion
Direct energy required per acre for irrigating crops (water-horsepower-hour/acre) is a function of the total
dynamic head, the amount of water applied and the type of fuel (natural gas, diesel, electricity and LP-gas)
employed to power the irrigation system (Rogers and Black 1992). Corn and alfalfa were the only feed
components that required irrigation. Direct energy expended by each fuel type is the product of waterhorsepower-hours/acre and the thermal value of each particular fuel. The percentage of acres irrigated
by a particular fuel type was then multiplied by its direct energy value and totaled to obtain a weighted
direct energy value per acre (Btuiacre).
In addition, energy embodied in engines and motors, pumps, gear heads, piping and tires of irrigation
systemswas determined. Material composition of each system component was determined and multiplied
by the appropriate embodied energy for that material. The total amount of energy embodied in each
irrigation system was calculated as the energy embodied in all system components divided by the expected
lifetime of the system and the number of acres irrigated by that system.
Fertilizers
and Pesticides
Direct energy consumed in the application of fertilizers was included in the data for fuels and lubricants.
Energy to apply pesticides was determined from the average fuel consumed per acre and the number of
applications per acre. A national average of 0.13 gallons per acre was used for fuel consumption of
pesticide application vehicles (Fluck 1992).
Energy embodied in fertilizers (nitrogen, phosphate and potassium) and pesticides per acre (Btu/acre) was
determined by multiplying the quantity (lbs) of fertilizer and pesticide applied per acre by the embodied
energy per pound of each type. Energy embodied in pesticides includes energy for manufacturing,
formulation, packaging, distribution, and transport (Fluck 1992). The amount of fertilizer and pesticide
applied per acre was calculated as the product of the percentage of acres covered by each fertilizer and
pesticide type and the application rate (lbs/acre) (Kansas Cooperative Extension Service 1991 and 1992).
Seeds
The amount of energy required to produce, process and transport crop seed was determined from
methodology provided by Heichel (1980) and is the product of the pounds of seed planted per acre, the
cost per pound, and the national energy intensity (Btu/GNP$). Seeding rates and cost per pound for each
type of seed were provided by KSU Cooperative Extension Service (Fjell 1993). The energy intensity
used in these calculations was 15,635 Btu per 1989 GNPS (Fluck 1992).
854
Transportation
Direct and embodied energy consumed per ton of feed ration and head of cattle transported was calculated
as the product of the direct or embodied energy value of diesel fuel, the mileage that each feed commodity
or head was transported and a transportation energy coefficient defined as the gallons of fuel consumed
per ton-mile, both loaded and unloaded (Monthly Agri-Srats Report 1993). Mileages for each type of
transport were obtained from commodity brokers (Irsik-Doll
1993) and state government agencies (Kansas
State Board of Agriculture 1992).
Energy inputs to feed ration production/transport
tallow produced.
Feed/o
and animal transport totaled
144,950 Btu per gallon of
t Energy
Energy in the form of natural gas, electricity, and liquid fuels is needed to maintain the beef animal at the
feedlot. The energy required per head was obtained from data provided by Sweeten (1985) and Lipper
(1976). These energies were 1.01 MCF, 77.2 kW-h, and 1.70 and 0.83 gallons of diesel fuel and gasoline,
respectively, per head totaling 21,149 Btu per gallon of tallow produced.
Total energy input to the animal growth life cycle for feed ration production, feedlot maintenance and
animal transport was 166,099 Btu per gallon of tallow produced. The energy-profit ratio associated with
the energetics of the animal growth life cycle, the rendering plant operations and the transesterification
process is 0.49.
Table 3 presents direct and embodied energies and the energy-profit ratio associated with the animal
growth life cycle, rendering plant operations, and tallow transesterification
allocated on the basis of energy
input per gallon esterified (B&r/gallon).
Economic
Feasibility
This portion of the study involved performing three separate analyses to determine the cost of production
Wgallon)
associated with producing tallow and processing it into methyl tallowate.
Each of these
analyses had the same starting point as those defined in the energetic feasibility analysis.
Case #l : Tallow
Transesterification
Economics
Economic feasibility analyses for 3 million and 30 million gallon per year transesterification
units were
conducted.
Both analyses are based on the continuous-flow
transesterification
process advanced by
GmTech, Inc. (1993). Capital equipment costs are $1.00 and $0.50 per gallon for the 3 million and 30
million gallon per year units, respectively.
Methodology
is based on the ANL Biomass Cost Estimation Guide (Jaycor 1987). Capital costs for both
units include the transesterification
unit as well as glycerol recovery equipment.
Operating costs include
materials and supplies, labor and fringe, overhead, utilities and fuels, repair and maintenance, and
insurance. Table 4 presents a total cost analysis for a 30 million gallon per year esterification unit with
“base” costs of SO.13 per pound for the tallow feedstock, $0.28 per pound by-product credit for glycerol,
and electrical and natural gas rates of $O.O75/kW-h and $3.00/MCF, respectively.
855
TABLE
Direct
and Embodied
Energies
and Energy-Profit
Ratios
3 Energetic
Feasibility
Analysis
Cases
Case
1
Btu/gallon
Tallow Transesterification
Direct Energy
natural gas
electricity
25,451
1,144
Embodied
Energy
sodium hydroxide
methanol
process unit
773
13,850
----
Total Energy Requirements
Tallow Transesterification
2
41,218
Rendering
Plant Operations
Direct Energy
natural gas
electricity
Animal
EPR
3.07
42,857
8,776
for
51,633
1.36
Growth Life Cycle
Direct and Embodied
Inputs for:
Energy
Feed Ration Production
Transport
Feedlot Maintenance
Animal
for the
for
Embodied
Energy
Total Energy Requirements
Rendering
Plant Operations
3
3
and
140,424
21,149
Transport
Total Energy Requirements
Animal Growth Life Cycle
4,526
for
166,099
0.49
Sensitivity analyses were performed to determine the effect of varying feedstock price, by-product credit
for glycerol, and electrical and natural gas utility rates. Two scenarios are presented in each analysis: one
for “low” utility rates of SO.O6AcW-h and $2.75/MCF and the other for “high” utility rates of SO.O78/lcW-h
and S3SOiMCF.
Tables 5 and 6 present the findings of these sensitivity analyses for both sized units.
856
TABLE
Total
Cost Analysis
and Operating
Production
( Continuous-Flow
TOTAL
4
Costs Associated
Process,
30 million
COST
with Methyl Tallowate
gallons
per year )
ANALYSIS
A.
Total
B.
Real Annual Cost of Capital ,217 Fixed charge rate for 15-yr
book life nonregulated
firm (30% equity, 10% debt) and no
tax preferences
(from ANL Biomass Cost Estimation
Guide)
C.
Total Annual
D.
Sales and Administration
E.
Working
,F.
Annualized
G.
Total
H.
By-Product
Credits
22,500,OOO pounds of crude glycerol @ $0.28 per pound
6,750,OOO pounds of FFAIfat mix @$0.08 per pound
Capital
$15,000,000
Costs
Operating
Capital
Cost
[ l/12
Annual
$35,888,977
[ 10% of B and C ]
of (B+C+D)
Cost of Working
Capital
[ 12.5% of E ]
Total
J.
Total Transesterification
Overhead
Utilities
& Fringe
per kW-h
of NaOH @ $0.30 per pound
of methanol
@ $0.55 per gallon
of tallow @ $0.13 per pound
Benefits
8000 hours per year
$675,000
$1,854,127
$30,127,500
$120,000
$60,000
: (50% of Direct Labor)
3,520,OOO kW-h/year
763,530 MCF/year
26,400,OOO gal/year
I. 15E+08 gal/year
electricity
per MCF natural gas
per 1000 gallons washing water
per 1000 gallons cooling water
Maintenance
Insurance
COSTS
& Fuels :
$0.075
$3.00
$0.50
$0.30
$1.22
Cost per Gallon
@ $15.00/hour,
$6,300,000
$540,000
$36,666,900
Cost
OPERATING
Labor :Operator
$448,525
$43,506,900
I.
Materials & Supplies:
2,250,OOO pounds
3,371,140
gallons
2.32E+08
pounds
$3,914,398
$3,588,198
]
Cost
Net Annual
$3,255,000
: (2% of Capital
: (1% of Capital
Total Annual
Operating
$264,000
$2,290,590
$13,200
$34,560
$300,000
Costs)
$150,000
Costs)
Costs for Transesterification
857
$35,888,977
TABLE
5
Methyl Tallowate
Economic
Cost Analysis
( $ per gallon )
( 3 million
gallons
per year, continuous-flow
process
)
Low Utility
Rate
Feedstock
Cost
High Utility
Feedstock
Rate
Cost
By-Product
Credit
$0.10
$0.13
so.15
$0.10
$0.13
$0.15
$0.20
$1.21
$1.47
$1.24
$1.49
$1.67
$0.28
$1.15
$1.41
$1.64
$1.58
$1.18
$0.33
$1.12
$1.37
$1.54
$1.14
$1.43
$1.40
$1.61
$? .57
TABLE
6
Methyl Tallowate
Economic
Cost Analysis
( $ per gallon )
( 30 million
gallons
per year, continuous-flow
process
)
Low Utility
Rate
High Utility
Rate
Feedstock
Cost
Feedstock
Cost
By-Product
Credit
$0.10
$0.13
$0.15
$0.10
$0.13
$0.15
$0.20
$1.02
91.27
$1.44
$1.04
s1.47
SO.28
SO.96
$1.21
$1.38
$1.41
$0.33
$0.92
S1.18
$1.35
SO.98
$0.94
$1.30
$1.24
$1.20
$1.37
The cost per gallon of methyl tallowate produced varies from a low of SO.92 per gallon for the 30 million
gallon per year unit to a high of S1.67 per gallon for the smaller unit depending upon feedstock cost,
glycerol by-product credit and utility rate.
Feedstock cost had the greatest impact on production costs, Production costs rose an average of nearly
SO.26 per gallon when feedstock price increased from $0.10 to $0.13 per pound and the cost per gallon
increased an average of $0.43 per gallon when feedstock cost rose from $0.10 to $0.15 per pound.
An average difference of slightly less than $0.10 per gallon in production costs occurred when the glycerol
by-product credit varied from $0.20 to $0.33 per pound within a set feedstock cost and a low or high
utility rate scenario.
Utility rates within the tange specified did not have a pronounced
feedstock cost and by-product credit, the difference in production
rates averaged slightly greater than $0.02 per gallon.
858
effect on production cost. For a given
costs between the low and high utility
Case #2: Rendering
Plant
Economics
The cost of processing tallow at the rendering plant is a function of the amount and cost of electricity and
natural gas consumed in converting animal fat to a liquefied state (rendered tallow). Cost of labor, capital,
etc., were not included in these calculations.
Data supplied by a major Midwestern meat packer (Cargill
1993) revealed that the cost per gallon of tallow processed was $0.054 per gallon for electricity and $0.12
per gallon for natural gas at utility rates of $O.O6/kW-h and $2.SOIMCF, respectively, totaling $0.174 per
gallon.
An analysis was performed to determine the effect of differing electrical and natural gas rates on the cost
of processing tallow at a beef processing facility.
Processing costs ranged from a low of $0.1674 per
gallon at an electrical rate of SO.055 per kW-h and a natural gas rate of $2.75 per MCF to a high of
$0.2417 per gallon at electrical and natural gas rates of SO.090 per kW-h and $3.75 per MCF, respectively.
The total processing cost per gallon using the above electrical and natural gas data and “base” case data
for the transesterification
process is $1.594 for a 3 million gallon per year unit and $1.394 per gallon for
a 30 million gallon per year processing unit.
Case #3:
Animal
Growth
Life Cycle
Economics
The cost of raising and maintaining
beef cattle varies throughout the nation and has significant variance
within a particular state. For these reasons, the cost of producing beef cattle for tallow was not considered
in the economic analysis.
Table 7 presents energy-profit ratio and production cost data for each of the three tallow production and
processing areas. Cost of production data for the transesteritication
plant uses the “base” case scenario
of feedstock cost of SO.13 per pound, a glycerol by-product credit of SO.28 per pound, and utility/fuel
costs of $O.O75AcW-h and $3.00 per MCF. Cost of production for rendering plant operations applies to
the rendering process only.
TABLE
Energetic
Associated
Case
1
7
(Energy-Profit
Ratio) and Economic
with the Production
and Processing
Substitute
Diesel Fuel
Starting
Energy-Profit
Ratio
Point of Analysis
Transesterification
Cost Data ($/gallon)
of Beef Tallow into a
cost of
Production
Process
(a) 3 million
gal/yr
3.07
$1.42
(b) 30 million
gal/yr
3.07
$1.22
Plant Operations
1.36
0.49
$0.174
-----
2
Rendering
3
Animal
Growth
Life Cycle
859
Conclusions
This study involved performing
an energetic and economic feasibility analysis associated with the
production and processing of beef tallow to a diesel fuel substitute and an assessmentof the U.S. tallow
resource base.
The energy-profit
ratio was 3.07 when considering only the tmnsesterification
process; 1.36 when
rendering plant operations and transesterification
were considered; and 0.49 when the growth and
maintenance of the beef animal from conception to slaughter through transesterification
was considered.
Tallow as a source of liquid fuel should be regarded as an inevitable by-product of meat production.
The
energetics of tallow ester production preclude its intentional production for energy purposes.
The economic feasibility associated with producing methyl tallowate was analyzed for both a 3 and 30
million gallon per year continuous-flow
tmnsesterification
unit. Within each analysis, the sensitivity of
feedstock price, by-product credit and electric and natural gas utility rates on the cost of production was
investigated. Transesterification
costs ranged from SO.92 to $1.67 per gallon of methyl tallowate produced
depending upon conditions, and production costs averaged $0.174 per gallon higher when rendering plant
operations were included.
The United States tallow resource base averages approximately
6 billion pounds per year with the beef
processing industry contributing
nearly 3.5 billion pounds of edible and inedible tallow.
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