CASE STUDY OF AN ENERGY AND ENVIRONMENTAL INVENTORY FOR A MUNICIPAL HEAVY DUTY DIESEL EQUIPMENT FLEET Phil Lewis, PhD, PE Assistant Professor Civil & Environmental Engineering Oklahoma State University
June 10, 2014
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SIGNIFICANCE DE is an important human health concern and the construction industry is often overlooked as a source of DE • Long-term(chronic) effects: lung cancer, other forms of
lung damage • Short-term(acute) effects: irritation of the eyes and
throat, neurophysiological symptoms, respiratory symptoms • May exacerbate allergenic responses, increase asthma-
like symptoms
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SIGNIFICANCE DE is a major environmental problem • National Ambient Air Quality Standards(NAAQS)
criteria pollutants • • • •
Nitrogen Oxides (NOX) Sulfur Oxides (SOX) Particulate Matter (PM) Carbon Monoxide (CO)
• Hydrocarbons(HC) - precursor to ground level
ozone • Carbon dioxide (CO2) - greenhouse gas with global
warming impacts
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SIGNIFICANCE Lack of real-world scientific knowledge available to improve estimation and measurement capabilities needed to quantify DE emissions from construction activities • NIOSH(1983) survey estimated ~1.35 million workers
occupationally exposed to DE in 80,000 workplaces including Construction, Mining, Railroad, Freight, Transit, Automotive • NIOSH(1988) declared an urgent research need for
estimating and measuring DE for workers, but little effort has been made
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SIGNIFICANCE Activities required to construct the nation’s infrastructure are performed by heavy-duty diesel equipment • Approximately 2 million items of diesel-powered
equipment in the US • Can remain active for 30 years, so many items of
equipment are old, unregulated, and high-polluting machines • New engine technology/environmental regulations
helped reduce emissions • Operational strategies are needed to reduce DE
emissions even more
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Case Study: City of Stillwater Fleet • Includes following types of equipment • • • • • • •
Backhoes Bulldozers Excavators Motor Graders Skid Steer Loaders Tractors Wheel Loaders
• Emits pollutants including • • • • •
Nitrogen Oxides (NOx) Particulate Matter (PM) Hydrocarbons (HC) Carbon Monoxide (CO) Carbon Dioxide (CO2)
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Research Questions 1. What is the composition of the current fleet with regard
to equipment type, equipment age, engine power, and emissions reduction technology type? 2. How much is the equipment used, particularly on an
annual basis? 3. How much fuel is consumed and pollution emitted by
the fleet on an annual basis? 4. Which equipment subgroups in the fleet have the
greatest energy and environmental impacts on an annual basis? 5. Which individual items of equipment have the greatest
energy and environmental impacts on an annual basis?
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Equipment Attributes • Equipment type
• Engine model year • Engine horsepower • Annual activity • EPA Engine Tier • Tier 0 (Unregulated) • Tier 1 • Tier 2 • Tier 3 • Tier 4 Trans. • Tier 4 Final
Phased in between 1996-2013
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EPA NONROAD Emission Factors EFadj (NOx, HC, CO) = EFss x TAF x DF EFadj (PM ) = EFss x TAF x DF - SPMadj where: EFadj = final emission factor used in NONROAD, after adjustments for transient operation and deterioration (g/hp-hr) EFss = zero-hour, steady-state emission factor (g/hp-hr) TAF = transient adjustment factor (unitless) DF = deterioration factor (unitless)
SPMadj = adjustment to PM emission factor for variations in fuel sulfur content (g/hp-hr)
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Fuel Use and CO2 Factors EFadj (BSFC) = EFss x TAF EFadj(CO2) = (BSFC x 453.6 - HC) x 0.87 x (44/12) where:
BSFC = in-use adjusted fuel consumption factor (lb/hp-hr) 453.6 = conversion factor from pounds to grams HC
= in-use adjusted hydrocarbon emissions (g/hp-hr)
0.87 = carbon mass fraction of diesel 44/12 = ratio of CO2 mass to carbon mass
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Annual Fuel Use & Emissions Emissions(NOx, HC, CO, PM, CO2, BSFC) = Pop × Power × LF × A × EFadj (NOx, HC, CO, PM, CO2, BSFC) where: NOx, HC, CO, CO2 = total annual emissions for the specified pollutant (g/yr) BSFC = total annual fuel consumption (lb/yr) Pop = equipment population (=1 for one unit of equipment) Power = engine rated horsepower (hp) LF = engine load factor (fraction of available power) A = equipment average annual activity (hr/yr) EFadj (NOx, HC, CO, PM, CO2, BSFC) = engine emission factor (g/hp-hr) or BSFC factor (lb/hp-hr)
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RQ 1: Fleet Composition 47 Total Equipment Units
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RQ 1: Fleet Composition
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RQ 2: Annual Activity Item
EPA Engine Tier
Engine Power (hp)
Engine Load Factor
Engine Model Year
Engine Age (yr)
Total Activit y (hr)
Annual Activity (hr/yr)
BH 1 BH 2 BH 3 BH 4 BH 5 BH 6 BH 7 BH 8 BH 9 BH 10 BH 11 BH 12 BH 13 BH 14 BH 15 BH 16 BH 17
1 0 0 0 0 2 0 3 2 1 1 1 2 1 0 1 0
98 58 58 28 75 95 75 79 95 75 75 75 95 98 65 95 75
0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21
2002 1993 1992 1982 1995 2005 1997 2008 2007 1999 2000 2000 2007 2001 1991 2002 1997
9 18 19 29 16 6 14 3 4 12 10 11 4 10 19 9 13
3,811 4,305 3,549 2,078 4,655 2,379 4,136 1,418 2,402 5,654 3,925 2,597 1,103 3,290 4,013 1,378 1,915
423 239 187 72 291 397 295 473 601 471 393 236 276 329 211 153 147
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RQ 2: Annual Activity Item BD 1 BD 2 BD 3 EX 1 EX 2 MG 1 MG 2 SS 1 SS 2 SS 3 SS 4 SS 5 SS 6 SS 7 WL 1 WL 2
EPA Engine Tier 0 1 2 2 1 0 1 2 3 4 2 1 1 2 0 0
Engine Power (hp) 78 87 70 190 114 150 140 82 82 46 90 61 61 63 110 170
Engine Load Factor 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.59 0.59
Engine Model Year 1975 2002 2006 2003 1999 1982 2002 2007 2008 2009 2006 1998 2001 2005 1990 1972
Engine Age (yr) 36 8 5 8 12 29 8 4 3 2 5 13 10 6 20 38
Total Activity (hr) 1,765 2,171 959 2,464 7,284 1,860 2,401 294 164 501 515 1,869 1,019 345 7,935 1,643
Annual Activity (hr/yr) 49 271 192 308 607 64 300 74 55 251 103 144 102 58 397 43
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RQ 2: Annual Activity Item
TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 TR 10 TR 11 TR 12 TR 13 TR 14
EPA Engine Tier 0 1 2 1 0 1 0 0 0 0 1 0 2 0
Engine Power (hp) 43 81 35 36 37 30 38 33 70 40 80 85 114 18
Engine Load Factor 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59 0.59
Engine Model Year 1998 2001 2007 2001 1974 2001 1978 1979 1989 1996 2001 1995 2003 1985
Engine Age (yr) 12 10 4 10 37 10 33 32 22 15 10 16 8 26
Total Usage (hr) 585 944 380 3,948 2,040 785 3,207 2,569 4,477 3,931 5,102 766 776 3,124
Annual Activity (hr/yr) 49 94 95 395 55 79 97 80 204 262 510 48 97 120
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RQ 3 & 4: Fleet Fuel Use and Emissions Fuel
NOx
PM
HC
CO
CO2
Total (gal/yr)
Total (lb/yr)
Total (lb/yr)
Total (lb/yr)
Total (lb/yr)
Total (ton/yr)
Backhoes
5,879
1,177
180
252
1,350
68
Bulldozers
1,361
275
28
29
206
16
Excavators
3,826
783
55
58
220
44
Motor Graders
1,547
395
36
29
129
18
691
115
11
18
110
8
Tractors
3,988
876
126
132
724
46
Wheel Loaders
1,528
539
45
49
319
18
Fleet Total
18,820
4,161
482
567
3,058
218
Item
Skid Steers
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RQ 5: Individual Fuel Use and Emissions Fuel Item BH 1 BH 2 BH 3 BH 4 BH 5 BH 6 BH 7 BH 8 BH 9 BH 10 BH 11 BH 12 BH 13 BH 14 BH 15 BH 16 BH 17
BSFCadj (lb/hp-hr)
Total (gal/yr)
0.48 575 0.48 192 0.48 150 0.48 28 0.48 302 0.48 522 0.48 307 0.48 517 0.48 790 0.48 489 0.48 408 0.48 245 0.48 363 0.48 447 0.48 190 0.48 201 0.48 153 Subtotal 5,879
NOx
PM
HC
CO
CO2
EFadj (g/hp-hr)
Total (lb/yr)
EFadj (g/hp-hr)
Total (lb/yr)
EFadj (g/hp-hr)
Total (lb/yr)
EFadj (g/hp-hr)
Total (lb/yr)
EFadj (g/hp-hr)
Total (ton/yr)
6.2 7.6 7.6 7.6 7.6 5.2 7.6 3.6 5.2 6.2 6.2 6.2 5.2 6.2 7.6 6.2 7.6
119 49 38 7 77 90 78 63 137 101 84 51 63 92 48 41 39 1,177
1.0 1.5 1.5 1.7 1.5 0.5 1.5 0.5 0.5 1.0 1.0 1.0 0.5 1.0 1.5 0.9 1.5
19 10 8 2 16 8 16 9 12 17 13 8 6 14 10 6 7 180
1.2 2.3 2.3 4.2 2.3 0.8 2.3 0.4 0.8 1.2 1.2 1.2 0.8 1.2 2.3 1.2 2.3
23 15 11 4 23 15 23 7 22 20 16 10 10 18 15 8 12 252
6.2 9.3 9.2 13.3 9.3 6.1 9.3 6.1 6.1 6.2 6.2 6.2 6.1 6.2 9.3 6.1 9.1
119 60 46 12 94 107 95 106 162 102 84 50 74 92 59 41 47 1,350
693 689 689 682 689 694 689 695 694 693 693 693 694 693 689 693 689
6.6 2.2 1.7 0.3 3.5 6.0 3.5 6.0 9.2 5.7 4.7 2.8 4.2 5.2 2.2 2.3 1.8 68
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RQ 5: Individual Fuel Use and Emissions Fuel
NOx
PM
HC
CO
CO2
Item
BSFCadj (lb/hp-hr)
BD 1
0.41
127
6.6
33
0.6
3
1.1
5
5.6
28
592
1.5
BD 2
0.41
786
5.4
164
0.6
19
0.6
17
3.7
114
594
9.1
BD 3
0.41
447
4.5
78
0.3
5
0.4
7
3.7
64
595
5.2
Total EFadj Total EFadj Total EFadj Total EFadj Total EFadj Total (gal/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (ton/yr)
Subtotal 1,361
275
28
29
206
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EX 1
0.37
1,753
3.8
290
0.2
13
0.3
25
1.2
90
535
20
EX 2
0.37
2,073
5.5
494
0.5
43
0.4
33
1.4
130
535
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Subtotal 3,826
783
55
58
220
44
MG 1
0.37
288
8.0
100
0.5
7
0.7
9
4.3
54
534
3.3
MG 2
0.37
1259
5.4
295
0.5
30
0.4
20
1.4
75
535
15
Subtotal 1,547
395
36
29
129
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RQ 5: Individual Fuel Use and Emissions Fuel Item SS 1 SS 2 SS 3 SS 4 SS 5 SS 6 SS 7
BSFCadj (lb/hp-hr)
NOx
PM
HC
CO
CO2
Total EFadj Total EFadj Total EFadj Total EFadj Total EFadj Total (gal/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr) (ton/yr)
0.48 83 0.48 62 0.48 160 0.48 128 0.48 121 0.48 86 0.48 50 Subtotal 691 WL 1 0.37 1,307 WL 2 0.37 220 Subtotal 1,528
5.2 3.6 3.6 5.2 6.2 6.2 5.2 8.2 8.0
14 8 19 22 25 18 9 115 462 76 539
0.4 0.4 0.0 0.5 0.9 0.9 0.4 0.7 0.5
1 1 0 2 4 3 1 11 40 5 45
0.8 0.4 0.3 0.8 1.2 1.2 0.8 0.7 0.7
2 1 2 4 5 3 1 18 42 7 49
6.1 6.1 0.4 6.1 6.1 6.1 6.1 4.9 4.3
17 13 2 26 25 18 10 110 278 41 319
694 695 696 694 693 693 694 534 534
1.0 0.7 1.9 1.5 1.4 1.0 0.6 8.0 15 2.5 18
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RQ 5: Individual Fuel Use and Emissions Fuel
NOx
PM
Item
BSFCadj (lb/hp-hr)
Total (gal/yr)
EFadj (g/hp-hr)
Total (lb/yr)
TR 1 TR 2 TR 3 TR 4 TR 5 TR 6 TR 7 TR 8 TR 9 TR 10 TR 11 TR 12 TR 13 TR 14
0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.37 0.41 Subtotal
70 255 111 473 68 78 123 88 474 349 1,359 136 331 72 3,988
6.6 5.3 4.5 4.6 6.6 4.5 6.7 6.7 6.6 6.7 5.4 6.6 3.9 8.2
18 53 19 85 18 14 32 23 123 91 286 35 56 23 876
HC
CO
EFadj Total EFadj Total EFadj (g/hp-hr) (lb/yr) (g/hp-hr) (lb/yr) (g/hp-hr)
1.0 0.6 0.4 0.6 1.2 0.4 1.3 1.2 1.1 1.4 0.7 0.9 0.2 1.5
3 6 2 11 3 1 6 4 20 19 39 5 3 4 126
1.9 0.5 0.3 0.3 1.9 0.3 2.0 1.9 1.1 2.0 0.6 1.0 0.4 1.8
5 5 1 6 5 1 9 7 20 27 30 6 5 5 132
7.8 3.7 2.4 2.6 8.3 2.4 8.7 8.5 5.9 9.0 3.9 5.4 1.3 8.7
CO2 Total (lb/yr)
21 36 10 47 22 7 42 29 109 122 204 29 19 24 724
EFadj Total (g/hp-hr) (ton/yr)
589 594 595 595 588 595 588 588 593 589 594 593 535 589
0.8 3.0 1.3 5.5 0.8 0.9 1.4 1.0 5.5 4.0 16 1.6 3.8 0.8 46
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Conclusions • City of Stillwater has an equipment data management
system, but… • Some of the data is missing • Some of the data is inaccurate
• City of Stillwater fleet is “old and dirty” • Average unit age is 14 years (5 at 20+ years; 5 at 30+ years) • 72% at Tier 1 or less; only 3 units at Tier 3 or 4 • Data seems to support the claim that usage decreases as
the equipment gets older • E&E inventory analysis helps managers • Identify “worst offenders” in the fleet (single units and subgroups) • May lead to new metrics for fleet management decisions
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Recommendations • Keep equipment data management systems updated • Telematics has extraordinary potential to help but still in development • PEMS provides accurate data but instrumentation is expensive • Must identify strategies for large-scale replacements • Units with high E&E impact should receive priority • More work is needed to assess relationship between
equipment age and usage • Help with reassignment or removal of underutilized equipment
• E&E inventories help manage E&E concerns • Focus is not solely on economic impacts any longer
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Contact Information Phil Lewis, PhD, PE Assistant Professor School of Civil and Environmental Engineering Oklahoma State University 207 Engineering South Stillwater, OK 74078 405-744-5207
[email protected] 24