THE ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
U.S. Environmental Protection Agency
SOUTHERN RESEARCH
INSTITUTE
ETV Joint Verification Statement
TECHNOLOGY TYPE:
APPLICATION:
TECHNOLOGY NAME:
COMPANY:
ADDRESS:
WEB ADDRESS:
Electric Power and Heat Production using Renewable
Biogas
Combined Heat and Power System
CAT 379 engine/generator set with integrated Martin
Machinery CHP system
Patterson Farm
1131 Aurelius Springport Townline Rd.
Auburn, NY 13021
http: //clip .ny serda. org/facilities/details. cfm ?facility=70
The U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD) operates
the Environmental Technology Verification (ETV) program to facilitate the deployment of innovative
technologies through performance verification and information dissemination. The goal of ETV is to
further environmental protection by accelerating the acceptance and use of improved and innovative
environmental technologies. ETV seeks to achieve this goal by providing high-quality, peer-reviewed
data on technology performance to those involved in the purchase, design, distribution, financing,
permitting, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations, stakeholder groups that
consist of buyers, vendor organizations, and permitters, and with the full participation of individual
technology developers. The program evaluates the performance of technologies by developing test plans
that are responsive to the needs of stakeholders, conducting field or laboratory tests, collecting and
analyzing data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with
rigorous quality assurance protocols to ensure that data of known and adequate quality are generated and
that the results are defensible.
The Greenhouse Gas Technology Center (GHG Center), operated by Southern Research Institute
(Southern), is one of six verification organizations operating under the ETV program. A technology area
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of interest to some GHG Center stakeholders is distributed electrical power generation (DG), particularly
with combined heat and power (CHP) capabilities.
The GHG Center collaborated with the New York State Energy Research and Development Authority
(NYSERDA) to evaluate the performance of a Caterpillar Model G379 internal combustion engine and
generator - combined heat and power (CHP) system manufactured by Martin Machinery and fueled with
biogas generated at a dairy farm. The system is owned and operated by Patterson Farms near Auburn,
New York.
TECHNOLOGY DESCRIPTION
The Patterson Farm is a dairy farm in upstate New York housing approximately 1,725 cows and heifers.
Farm operations generate approximately 50,000 gallons per day of manure and process water. This waste
is collected and pumped to a complete mix anaerobic digester designed by RCM Digesters of Berkeley,
California. The digester's dimensions are approximately 135 by 125 by 16 feet deep with a total waste
capacity of approximately 270,000 cubic feet. Following the digester, solids are separated and composted
in a solids removal system. Composted solids are later used as animal bedding and separated liquids are
stored in a lagoon until used in the fields.
In addition to farm waste, operators also feed cheese whey waste generated off-site into the digester. The
anaerobic digestion system produces biogas that is typically about 45 percent methane and has an average
lower heating value (LHV) of approximately 525 Btu/scf. Approximately 4,800 cfh of the biogas is used
to fuel an on-site DG/CHP system, and the remainder is flared. The DG/CHP system consists of a
Caterpillar Model 379, 200 kW engine-generator set with integrated heat recovery capability. The engine
tested was not equipped with any add-on emission control equipment
Prior to being used as fuel, the wet biogas is passed through two Filtration Systems, Inc. Model G82308
water filtration units arranged in series to remove moisture from the gas. Dry biogas is then metered and
delivered to the engine. During normal farm operations, the engine generates nominal 187 kW power at
an electrical efficiency of approximately 22 percent. The facility is equipped with net power metering so
that excess power generated on-site can be exported to the grid and credited. The engine is equipped with
a heat recovery system that recovers heat to warm the digester. Excess heat is dissipated through a
radiator. Water with trace amounts of rust inhibitor is used as the heat transfer fluid. The farm has plans
to expand engine heat use by supplying hot water to the milking parlor in the future. This expansion
would increase biogas utilization at the site, decrease flare emissions, and improve thermal efficiency of
the CHP system.
VERIFICATION DESCRIPTION
Field testing was conducted from May 2, 2007 through May 26, 2007. The defined system under test
(SUT) was tested to determine performance for the following verification parameters:
Electrical Performance
Electrical Efficiency
CHP Thermal Performance
Emissions Performance
NOX and CO2 Emission Offsets
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The verification included a series of controlled test periods on May 2, 2007 in which the GHG Center
maintained steady system operations for three one-hour test periods at three loads: 100%, 75%, and 50%
of capacity (200, 150, and 100 kW, respectively) to evaluate electrical and CHP efficiency and emissions
performance. The controlled tests were followed by a 7-day period of continuous monitoring to examine
heat and power output, power quality, efficiency, and estimated annual emission reductions.
Rationale for the experimental design, determination of verification parameters, detailed testing
procedures, test log forms, and QA/QC procedures can be found in the draft ETV Generic Verification
Protocol (GVP) for DG/CHP verifications developed by the GHG Center. Site specific information and
details regarding instrumentation, procedures, and measurements specific to this verification were
detailed in the Test and Quality Assurance Plan titled Test and Quality Assurance Plan - Electric Power
and Heat Production Using Renewable Biogas at Patterson Farms.
Quality assurance (QA) oversight of the verification testing was provided following specifications in the
ETV Quality Management Plan (QMP). The GHG Center's QA manager conducted an audit of data
quality on a representative portion of the data generated during this verification and a review of this
report. Data review and validation was conducted at three levels including the field team leader (for data
generated by subcontractors), the project manager, and the QA manager. Through these activities, the
QA manager has concluded that the data meet the data quality objectives that are specified in the Test and
Quality Assurance Plan.
VERIFICATION OF PERFORMANCE
Electrical and Thermal Performance
Table S-l. Patterson Farms DG/CHP System Electrical and Thermal Performance
Test ID
200
kW
150
kW
100
kW
Runl
Run 2
Run3
Avg.
Runl
Run 2
Run3
Avg.
Runl
Run 2
RunS
Avg.
Heat
Input
(MBtu/h)
2.45
2.44
2.44
2.45
2.39
2.40
2.39
2.39
2.36
2.36
2.37
2.36
Electrical Power
Generation Performance
Power
Generated
(kW)
192
191
190
191
153
153
153
153
104
104
104
104
Electrical
Efficiency
(%)
26.8
26.6
26.6
26.7
21.8
21.8
21.9
21.8
15.0
15.0
15.0
15.0
Digester Loop Heat
Recovery Performance
Heat
Recovered
(MBtu/h)
0.164
0.215
0.218
0.199
0.0907
0.142
0.141
0.125
0.114
0.0237
0.0131
0.0502
Thermal
Efficiency
(%)
6.72
8.77
8.94
8.14
3.79
5.93
5.89
5.20
4.84
1.00
0.553
2.13
CHP
Efficiency
(%)
33.5
35.4
35.5
34.8
25.6
27.7
27.8
27.0
19.9
16.0
15.5
17.1
Radiator
Loop Heat
Rejected
(MBtu/h)
1.60
1.34
1.34
1.42
2.21
1.60
1.59
1.80
1.73
6.15
7.63
5.17
Electrical efficiency averaged approximately 26.7 percent at this site at 200 kW, 21.8 percent at 150 kW,
and 15.0 percent at 100 kW.
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Heat recovery and use during the controlled test periods averaged 0.199 MBtu/h at 200 kW, 0.125
MBtu/h at 150 kW, and 0.00502 MBtu/h at 100 kW. Due to low thermal demand in the digester, the
majority of heat generated by the CHP system was dissipated through the radiator loop. Thermal
efficiency for the digester loop at this site averaged 8.14 percent at 200 kW, 5.20 percent at 150 kW, and
2.13 percent at 100 kW.
Runs 2 and 3 at 50% load (100 kW) showed substantially lower heat recovered and thermal efficiency for
the digester loop than that measured during Run 1. Examining the data showed that water flow in the
digester loop dropped significantly during Runs 2 and 3. During these runs, it appears that heat stopped
going to the digester and was instead dumped to the radiator, as shown by the increased radiator loop heat
rejected. Run 1 is more representative of normal heat recovery performance for the digester at 50% load.
During the 7-day monitoring period, the system operated for a total of total of approximately 167 hours,
or 99 percent of the time. During this time, atotal of 32,239 kWh of electricity was generated. Net
electrical efficiency during the monitoring period averaged 28 percent and thermal efficiency for the
digester heat recovery loop averaged 18 percent, for a total CHP efficiency of 46 percent.
Emissions Performance
Table S-2. Patterson Farms DG/CHP System Emissions during Controlled Tests
TA«f TT1
200 kW
150 kW
100 kW
Runl
Run 2
Run3
Avg.
Runl
Run 2
Run3
Avg.
Runl
Run 2
RunS
Avg.
Power
(kW)
192
191
190
191
153
153
153
153
104
104
104
104
CO Emissions
ppm
182
354
337
291
21600
22300
22400
22100
29700
29900
30300
30000
Ib/h
0.389
0.755
0.718
0.621
40.1
41.5
41.7
41.1
52.5
52.9
53.5
53.0
Ib/kWh
0.00202
0.00396
0.00378
0.00325
0.262
0.272
0.272
0.269
0.506
0.509
0.516
0.510
CO2 Emissions
ppm
127000
128000
129000
128000
129000
131000
131000
130000
123000
124000
124000
123000
Ib/h
271
274
276
274
240
243
243
242
217
219
220
218
Ib/kWh
1.41
1.44
1.45
1.44
1.57
1.59
1.59
1.58
2.09
2.11
2.12
2.10
The average CO emission rate normalized to power output was 0.00325 Ib/kWh for the 100%
load tests, 0.269 Ib/kWh at the 75% load tests, and 0.510 Ib/kWh for the 50% load tests.
THC emissions averaged 0.0202 Ib/kWh at 100% load, 0.0359 Ib/kWh at 75% load, and
0.0539 Ib/kWh at 50% load. NOX emissions averaged 0.0213 Ib/kWh at 100% load, 0.00521
Ib/kWh at 75% load, and 0.00123 Ib/kWh at 50% load.
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Table S-2 continued. Patterson Farms DG/CHP System Emissions during Controlled Tests
TWf TTl
200 kW
150 kW
100 kW
Runl
Run 2
Run3
Avg.
Runl
Run 2
Run3
Avg.
Runl
Run 2
RunS
Avg.
Power
(kW)
192
191
190
191
153
153
153
153
104
104
104
104
THC Emissions
ppm
1840
1810
1790
1810
2950
2920
2960
2950
3220
3170
3100
3160
Ib/h
3.92
3.86
3.81
3.87
5.49
5.44
5.50
5.48
5.70
5.61
5.48
5.59
Ib/kWh
0.0204
0.0203
0.0200
0.0202
0.0359
0.0355
0.0359
0.0359
0.0549
0.0540
0.0529
0.0539
NOx Emissions
ppm
1870
1890
1950
1910
409
430
447
429
71.9
73.3
70.8
72.0
Ib/h
3.99
4.04
4.17
4.07
0.760
0.800
0.832
0.797
0.127
0.130
0.125
0.127
Ib/kWh
0.0208
0.0212
0.0219
0.0213
0.00497
0.00523
0.00543
0.00521
0.00123
0.00125
0.00121
0.00123
Compared to the EGrid baseline emissions scenarios for the New York State and national grid
regions, changes in annual NOX emissions caused by use of the SUT are estimated to be about 31,700
Ib/y higher for New York State and 29,300 Ib/y higher for the national scenario. CO2 emission rates
averaged 1.44 Ib/kWh at 100% load, 1.58 Ib/kWh at 75% load, and 2.10 Ib/kWh at 50% load. For
CO2, reductions in estimated annual emissions for the New York State and national grid (including
CO2 equivalent emissions eliminated through the use of waste CFU at the farm), are 13,613,000 Ib/y
14,272,000 Ib/y, respectively.
Power Quality Performance
Average electrical frequency was 60.0 Hz and average power factor was 99.7 percent.
The average current TFID was 5.90 percent and the average voltage TFID was 3.14 percent. The IEEE
recommended threshold for THD is 5 percent.
Details on the verification test design, measurement test procedures, and Quality Assurance/Quality Control
(QA/QC) procedures can be found in the Test Plan titled Test and Quality Assurance Plan - Electric Power
and Heat Production Using Renewable Biogas at Patterson Farms (Southern 2007). Detailed results of the
verification are presented in the final report titled Environmental Technology Verification Report - Electric
Power and Heat Production Using Renewable Biogas at Patterson Farms (Southern 2007). Both can be
downloaded from the GHG Center's web-site (www.sri-rtp.com) or the ETV Program web-site
(www.epa.gov/etv).
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Signed by Sally Gutierrez (10/09/2007) Signed by Tim Hansen (09/26/2007)
Sally Gutierrez Tim Hansen
Director Director
National Risk Management Research Laboratory Greenhouse Gas Technology Center
Office of Research and Development Southern Research Institute
Notice: GHG Center verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. The EPA and Southern Research Institute
make no expressed or implied warranties as to the performance of the technology and do not certify that a
technology will always operate at the levels verified. The end user is solely responsible for complying with any and
all applicable Federal, State, and Local requirements. Mention of commercial product names does not imply
endorsement or recommendation.
EPA REVIEW NOTICE
This report has been peer and administratively reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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