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Fleet GHG Performance An Overview of Issues and Options

Fleet GHG Performance An Overview of Issues and Options . Transportation Work Group Phase III - Meeting 1 October 30, 2003 . Meszler Engineering Services 906 Hamburg Drive Abingdon, Maryland 21009. 410-569-0599 www.meszler.com. Viable Fleet GHG Reduction Options. Selective purchase.

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Fleet GHG Performance An Overview of Issues and Options

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  1. Fleet GHG PerformanceAn Overviewof Issues and Options Transportation Work Group Phase III - Meeting 1 October 30, 2003 Meszler Engineering Services 906 Hamburg Drive Abingdon, Maryland 21009 410-569-0599 www.meszler.com

  2. Viable Fleet GHG Reduction Options • Selective purchase. • Purchase carbon efficient vehicles -- high fuel efficiency, low carbon fuel. • Current market offers vehicles with a range of fuel efficiency in all vehicle classes. • Undertake aftermarket efficiency improvements (aftermarket = after manufacturer delivery). • Implement a rigorous maintenance program. • Control VMT/speed. Page 2

  3. Selective Purchase Options • Select the smallest, most fuel efficient vehicle that will do the job (FC increases with vehicle mass). • Select vehicles powered by low carbon fuels: • Diesel: 22.4 pounds CO2 per gallon consumed • Gasoline: 19.5 pounds CO2 per gallon consumed • E85: 14.9 pounds CO2 per gallon consumed • CNG: 14.1 pounds CO2 per gallon consumed (1) • LPG: 13.5 pounds CO2 per gallon consumed (1) CNG is based on 121.5 ft3 per gallon equivalent (U.S. DOT). All others are liquid gallon figures. Page 3

  4. Selective Purchase - 2003 FC by Class Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 4

  5. EPACT Purchase Implications • EPACT - Limits flexibility of state (and fuel provider) fleets. • NG options are generally low GHG. • Reductions of 10-20% could be achieved by purchase of lowest consumption gasoline vehicles in the large car and pickup truck classes (limited NG availability). • E85 generally a poor choice (poor fuel efficiency). • Must use the EPACT fuel to get GHG benefits. Page 5

  6. Aftermarket Efficiency Improvements • Some aftermarket technologies are superior to others from a GHG perspective. • Advanced lubricating oils reduce GHG relative to higher viscosity alternatives. • Friction reduction (up to 3% GHG benefit). • Tire design can also reduce GHG. • Reduced rolling resistance (up to 6% GHG benefit). Page 6

  7. Improved Maintenance (a) • Maintenance can significantly impact GHG. • A proper tune-up can improve FC by 4-30% • Improvement depends on severity of need (high end of range is associated with malperforming O2 sensor -- low end of range typical). • A dirty air filter can increase FC by as much as 10% through increased air restriction. Page 7

  8. Improved Maintenance (b) • Under-inflated tires can increase FC by about 1% for every 3 psi. • An 8/01 NHTSA study found that about 30% of light duty vehicles had at least one tire under-inflated by 8 psi or more. • Average under-inflation was about 1 psi for PC and 2 psi for LT. Page 8

  9. Operational Changes (a) • Operational characteristics directly affect GHG. • VMT. • VMT reductions translate into direct GHG reductions, but are difficult to implement and enforce. • Reduced vehicle idling. • Idling restrictions are in place in many jurisdictions, but enforcement varies. Page 9

  10. Operational Changes (b) • Aggressive driving and speed also strongly influence fuel consumption and GHG. • Increase in FC (from 55 mph) is about: • 3% at 60, 10% at 65, 20% at 70, 30% at 75 • Nationally, 20% of VMT is >55 mph. Page 10

  11. Model for State Fleet Legislation • In California, SB552 (Burton) requires (pending signature) the state to adopt standards: • To dispose of nonessential SUVs and 4WD pickups from the state fleet. • To use low carbon fuel in state bi-fuel vehicles. • To purchase best-in-class vehicles. • Upcoming NESCAUM presentation will provide additional information on activity in other states. Page 11

  12. Additional Detail and Expanded Explanations of Technical Issues Page 12

  13. General Methods to Reduce GHG (a) • Vehicle technology improvement - decrease fuel consumption (FC) per mile (or per minute at idle). • Generally this translates to an increase in fuel economy, but fuel consumption decreases at a slower rate than fuel economy (FE) increases. • For small changes in FE, the difference between FE and FC change is small -- but significant for larger changes. • 15% FE increase is 13% FC decrease, but 50% and 100% FE increases are 33% and 50% FC decreases. Page 13

  14. General Methods to Reduce GHG (b) • Select the smallest vehicle that will do the job (FC increases with vehicle mass). • Select vehicles powered by low carbon fuels: • Diesel: 22.4 pounds CO2 per gallon consumed • Gasoline: 19.5 pounds CO2 per gallon consumed • CNG: 14.1 pounds CO2 per gallon consumed (1) • LPG: 13.5 pounds CO2 per gallon consumed • E85: 14.9 pounds CO2 per gallon consumed (1) CNG is based on 121.5 ft3 per gallon equivalent (U.S. DOT). All others are liquid gallon figures. Page 14

  15. General Methods to Reduce GHG (c) • To determine overall GHG impact, use of reduced carbon fuel must also consider: • Any impact on overall FC. • Any change in methane (CH4) or nitrous oxide (N2O) emissions (1 g CH4 = 21 g CO2, 1 g N2O = 310 g CO2) • Improve performance of “off-cycle” technology. • E.g., air conditioning energy demand or reduced GHG refrigerant (neither are considered in current CAFE requirements --- 1 g HFC134a = 1300 g CO2). Page 15

  16. Selective Purchase (2003 FE by Class) Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 16

  17. Selective Purchase (2003 FC by Class) Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 17

  18. Selective Purchase (2003 FC Range) Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 18

  19. Selective Purchase (2003 CO2 by Class) Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 19

  20. Selective Purchase (2003 CO2 Range) Data include automatic transmission vehicles only, manual transmission versions with 3-5 percent lower fuel consumption are available for many models. Page 20

  21. Best/Worst Gasoline AT Vehicles - 2003 Page 21

  22. Selective Purchase and Displacement (a) • Much of fuel consumption difference is due to engine size options within classes. Lower GHG generally correlates with lower engine size. – Vans are exception, but range of GHG is generally less as well. – So, potential of selective purchase depends on minimum engine size needed to do “the job.” Page 22

  23. Selective Purchase and Displacement (b) • How much difference does displacement make? • Example, 4WD SUV -- best vs. worst -- Honda CR-V vs. Dodge Durango -- Durango has 71% higher CO2 emissions and costs about $8K more: • The differences are clear, but does it transport more than people? Page 23

  24. Aftermarket Efficiency Improvements • Some aftermarket technologies are superior to others. • Energy consumption influences for a given operational demand are: engine thermal efficiency, friction and pumping losses, drivetrain losses, accessory loads, vehicle mass, aerodynamic drag, and rolling resistance. • Of these, engine friction and rolling resistance can be affected by aftermarket technology. • Friction loss can be improved through advanced lube oil, rolling resistance through tire design. Page 24

  25. Advanced Lubricating Oils (a) • Low viscosity lube oils have become widely available. • 10W and 5W oils are dominant, and 0W is on the market (#W indicates winter viscosity, with lower #s indicating increased fluidity -- lower friction). • Reduced viscosity 10W-20, 5W-30, and 5W-20 formulations widely available, along with 0W-20 (the second # indicates summer viscosity, with with lower #s indicating increased fluidity -- lower friction). • 5W-30 is the dominant factory fill oil, with significant use of 5W-20 -- the Honda Insight uses 0W-20. Page 25

  26. Advanced Lubricating Oils (b) • Maintaining factory fill oil will not improve FC, but moving to more advanced grades can provide benefits. • 1% or so from 10W-30 to 5W-30 ($0.20-$0.30/quart). • 1% or so from 5W-30 to 5W-20 ($0.25-$0.50/quart). • Another 1% or so from 5W-20 to 0W-20 ($1.50+/qt). • Benefits dependent on age and current practice. • Newer vehicles with advanced factory fill oil will see least benefit, except in cases where current practice results in in-use degradation (higher viscosity). Page 26

  27. Rolling Resistance Improvements (a) • Rolling resistance (RR) is a measure of the force required to overcome tire structural inertia and road friction. • Low rolling resistance (LRR) tires require less energy to induce a given vehicle movement. • Generally the ratio between FC and RR is about 1:6 -- a 1% reduction in FC for every 6% reduction in RR. Page 27

  28. Rolling Resistance Improvements (b) • OEMs recognize the benefits of LRR (for CAFE) and most original equipment tires exhibit coefficients of RR (Cr) is the range of 0.008-0.012 (lower Cr means higher efficiency). • Performance tires and large truck tires can exhibit Cr in the range 0.011-0.014. • There is some trade off between LRR and acceleration/braking performance and OEMs balance tire selection accordingly. Page 28

  29. Rolling Resistance Improvements (c) • However, styling is also a factor and tires wider than required for safety or performance are often used on larger vehicles. • Moreover, tire replacement seldom considers RR, or even maintaining factory-level specifications. • A 1/03 California Energy Commission study found replacement tire Cr to be within the ranges previously noted -- but consumers have no way to identify high RR from LRR tires. Page 29

  30. Rolling Resistance Improvements (d) • In response to this lack of information, California passed AB844 (nation) requiring tire efficiency labeling in the state beginning in 2008. • In the interim, Green Seal (an environmental organization) has published a list of recommended LRR replacement tires, with Cr from 0.0062 to 0.0105. • The upper end of the range is typical of factory tire performance; the lower end a FC reduction of ~7%. Page 30

  31. Rolling Resistance Improvements (e) • For a 185/70R14 tire, Cr=0.006-0.0085 tires are about $35 more expensive than Cr=0.009-0.0105. • Similar cost delta exists for a 235/75R15 with Cr=0.008 versus Cr=0.009. • As with advanced lube oil, actual benefits will depend on current tire replacement practice. Page 31

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