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3 The researchersâ review of clean truck strategies covered the following categories: â¢ Engine and aftertreatment technologies â targeting criteria pollutants, â¢ Engine and powertrain technologies â targeting fuel efficiency, â¢ Alternative fuels, â¢ Vehicle technologies â targeting fuel efficiency, â¢ Operational strategies, and â¢ Clean truck corridor infrastructure. The researchers completed a literature review that considered more than 50 documents cover- ing more than 45 individual strategies. For each strategy, the researchers assessed the following information: â¢ Segments of the truck population to which the strategy is applicable; â¢ Reported fuel and emissions impacts in terms of GHGs, PM, NOx, and volatile organic compounds (VOCs) (for gasoline trucks); â¢ Costs (capital and operating); â¢ Current commercial availability or expected timeframe for availability; and â¢ Examples of deployment. Full details of the review were included in the Task 2 technical memo, submitted in November 2014. This section summarizes key findings from that memo. 2.1 Engine and Aftertreatment Technologies â Targeting Criteria Pollutants These strategies focus (see Table 1) on reducing criteria pollutant emissions (primarily NOx or PM) from trucks. They include exhaust retrofit devices such as diesel oxidation catalysts (DOCs) and diesel particulate filters (DPFs). With the introduction of trucks that comply with the EPA model year (MY) 2007/2010 emission standards, exhaust retrofits are now appropriate only for older trucks. Replacement of older trucks with newer vehicles that meet the 2007/2010 emission standards is another strategy in this category. Some older trucks can also be repowered with newer, cleaner engines, but repowering older trucks with MY 2007/2010 engines may be difficult because of differing physical configurations. â¢ DOC. A DOC is an aftertreatment device that reduces carbon monoxide, hydrocarbons, and the organic carbon component of PM. Exhaust gases flow through a ceramic honeycomb structure coated with rare earth metals, which catalyze the oxidation of the pollutants, con- verting them to carbon dioxide and water vapor. The DOC is typically housed in a stainless C H A P T E R 2 Clean Truck Strategies
4 Guide to Deploying Clean Truck Freight Strategies steel structure connected to the exhaust system muffler. DOCs have limited PM benefits and do not reduce NOx. They are only appropriate for older (pre-2007) trucks. â¢ DPF. A DPF is an aftertreatment device that captures PM from the exhaust gas flow. Most of the DPFs sold in the United States use substrates consisting of ceramic wall-flow monoliths to capture the diesel particulates; silicon carbide or other metallic substrates are also available but less common. To prevent plugging of the filter, filtered PM must be oxidized through a regeneration process. DPFs do not reduce NOx. They are only appropriate for older (pre-2007) trucks. â¢ Truck replacement. Replacing older diesel trucks with newer (MY 2010+) diesel models can significantly reduce PM and NOx emissions. However, trucks typically have useful lifespans longer than a decade and will often remain in service as long as the operating and mainte- nance costs do not exceed the purchase price of a newer vehicle or as long as the vehicle meets regulations. Incentives to replace older vehicles with cleaner alternatives can accelerate the retirement of trucks not meeting 2007/2010 emission standards. 2.1.1 Bibliography for Assessing Emissions Impacts of Engine and Aftertreatment Strategies California Air Resources Board (CARB). Carl Moyer Program: On-Road Heavy-Duty Vehicle Incentive Program (VIP). http://www.arb.ca.gov/msprog/moyer/voucher/voucher.htm. CARB. Truck and Bus Regulation: On-Road Heavy-Duty Diesel Vehicles (In-Use) Regulation. http://www.arb. ca.gov/msprog/onrdiesel/onrdiesel.htm. CARB. Staff Report: Initial Statement of Reasons (ISOR), Appendix G: Emissions Analysis Methodology and Results. 2010. Retrieved from http://www.arb.ca.gov/regact/2010/truckbus10/truckbusappg.pdf. Couch, P., and J. Leonard. Exhaust Temperature Testing on Heavy-Duty Drayage Trucks to Assess Applicability of Diesel Particulate Filters, Summary Report. 2007. Prepared for Port of Long Beach, Port of Los Angeles, and Gateway Cities Council of Governments. DieselNet. Technology Guide: Diesel Exhaust Gas. https://www.dieselnet.com/tech/diesel_exh_pres.php. Port Authority of New York & New Jersey (PANYNJ). Truck Replacement Program. http://www.panynj.gov/ truckers-resources/truck-replacement.html. Port of Seattle. Clean Truck Program. http://www.portseattle.org/Environmental/Air/Seaport-Air-Quality/ Pages/Clean-Trucks.aspx. Strategy Applicability Fuel and Emissions Reduction Cost per Truck AvailabilityFuel/GHGs PM NOx VOC DOC Only older trucks (pre-2007) None 20%â 40% None 40%â 70% $600 to $4,000 Widely available DPF Only older trucks (pre-2007) None 85%â 95% None 85%â 95% $8,000 to $20,000 Widely available Accelerated retirement of pre-2007 trucks; replacement with MY 2010+ Only older trucks (pre-2007) None 90% 90% 90% $50,000 to $100,000 Widely available Table 1. Summary of engine and aftertreatment technologies â targeting criteria pollutants.
Clean Truck Strategies 5 U.S. EPA. National Clean Diesel Campaign Diesel Retrofit Devices. http://www.epa.gov/cleandiesel/technologies/ retrofits.htm. U.S. EPA. National Diesel Emission Reduction Grants. http://www.epa.gov/cleandiesel/projects-national.htm. U.S. EPA, Office of Transportation and Air Quality. Second Report to Congress: Highlights of the Diesel Emissions Reduction Program. 2010. Retrieved from http://www.epa.gov/cleandiesel/. 2.2 Engine and Powertrain Technologies â Targeting Fuel Efficiency A variety of existing and emerging technologies for engines and powertrains can reduce fuel consumption and GHG emissions (see Table 2). These include a spectrum of electrification tech- nologies ranging from mild hybrid-electric systems with small energy storage capacity, aggressive hybrid systems with plug-in capabilities, to full battery-electric vehicles. â¢ Hybrid-electric vehicle (HEV). Hybrid-electric technology increases system efficiency by intro- ducing an electric motor and generator, an energy storage device (e.g., a battery), and power electronics. The electric motor and generator absorb energy via regenerative braking and store that energy in, for instance, a battery to offset acceleration and power demands of the vehicle. This system is optimized for vehicles depending on the demands of the likely duty cycle. HEV technology is most suitable for Class 3 to Class 6 trucks in urban operation; current models are available from Kenworth, Hino, Peterbilt, and Freightliner. â¢ Plug-in hybrid-electric vehicle (PHEV). Plug-in hybrid technology advances the configura- tion of HEVs. The battery is generally larger, and the user can plug the vehicle in to recharge the battery. This is the primary difference in the plug-in vehicle design, as the battery is not Strategy Applicability Fuel and Emissions Reduction Cost per Truck AvailabilityFuel/GHGs PM NOx VOC HEV All trucks; especially Classes 3â6 10%â20% 10%â 20% 10%â 20% 10%â 20% 30%â50+% more than conventional Current models from Kenworth, Hino, Peterbilt, Freightliner PHEV All trucks; especially Classes 3â6 30%â60% 30%â 60% 30%â 60% 30%â 60% 2â3 times more than conventional Limited. Current developers: Smith Newton, Odyne Systems BEV All trucks; especially Classes 3â6 100% reduction in fuel; 40%â 60% reduction in GHGs 80% 100% 100% 2â3 times more than conventional Limited. Current developers: Balqon, Capacity Trucks, Boulder Electric Vehicle, EVI, Enova Systems, Smith Electric, ZeroTruck Alternative Fuelâ Hybrid Combinations All trucks; especially Classes 3â6 Varies Varies Varies Varies 20%â30% more than conventional None currently Table 2. Summary of engine and powertrain technologies targeting fuel efficiency.
6 Guide to Deploying Clean Truck Freight Strategies solely dependent on regenerative braking or the onboard engine for energy. PHEV technology is most suitable for Class 3 to Class 6 trucks in urban operation. This technology is currently in development and demonstration, with very limited commercial availability. Smith Newton and Odyne Systems are the primary manufacturers of plug-in electric diesel trucks in the United States. PHEV trucks will likely require direct current (DC) fast charging infrastructure, which varies widely in cost but is roughly estimated at $150,000 per unit. â¢ Battery-electric vehicle (BEV). BEVs replace the entire engine and drivetrain of a conven- tional vehicle with an electric motor/generator, powered by a battery pack. The range of BEVs is dependent on the battery technology and the size of the battery pack. This technology eliminates tailpipe emissions. GHG impacts will depend on the source of power used to charge the batter- ies. BEV trucks currently have limited commercial availability, with small numbers produced by emerging manufacturers. Costs are likely 2 to 3 times a conventional truck, depending mainly on the battery size. â¢ HEV + alternative fuels. Hybrid drivetrains can be combined with engines that use alternative fuels for increased fuel efficiency and emissions reductions. 2.2.1 Bibliography for Estimating Emissions and Fuel Impacts of Engine and Powertrain Technologies CalHEAT Truck Research Center. Research and Market Transformation Roadmap for Medium and Heavy-Duty Trucks. 2013. Prepared for the California Energy Commission. Retrieved from http://www.calstart.org/ Libraries/CalHEAT_2013_Documents_Presentations/CalHEAT_Roadmap_Final_Draft_Publication_ Rev_6.sflb.ashx. CalHEAT Truck Research Center. Market Barriers and Opportunities for Alternative Fuel Hybrid Systems. 2013. Prepared for the California Energy Commission. Retrieved from http://www.calstart.org/Libraries/ CalHEAT_2013_Documents_Presentations/CalHEAT_Market_Barriers_and_Opportunities_for_ Alternative_Fuel-Hybrid_Systems.sflb.ashx. Gladstein, Neandross, & Associates. Moving California Forward: Zero- and Low-Emissions Goods Move- ment Pathways. 2013. Prepared for the California Cleaner Freight Coalition. Retrieved from http://www. ucsusa.org/sites/default/files/legacy/assets/documents/clean_vehicles/Moving-California-Forward- Report.PDF. ICF International. SCAG Comprehensive Regional Goods Movement Plan and Implementation Strategy: Task 10.2 Evaluation of Environmental Mitigation Strategies. 2012. Retrieved from http://www.freight works.org/DocumentLibrary/Task%2010%202%20report%20April%202012%20final%20no%20 watermark.pdf. Lee, D. Y., V. M. Thomas, and M. A. Brown. Electric Urban Delivery Trucks: Energy Use, Greenhouse Gas Emis- sions, and Cost-Effectiveness. Environmental Science & Technology, 47.14, 2013, pp. 8022â8030. National Renewable Energy Laboratory. FedEx Express Gasoline Hybrid Electric Delivery Truck Evaluation: 12-Month Report. 2011. Prepared for the DOE Advanced Vehicle Testing Activity. Retrieved from http:// www.nrel.gov/vehiclesandfuels/fleettest/pdfs/48896.pdf. National Renewable Energy Laboratory. Eighteen-Month Final Evaluation of UPS Second Generation Diesel Hybrid- Electric Delivery Vans. 2012. Report prepared for the DOE Advanced Vehicle Testing Activity. Retrieved from http://www.nrel.gov/docs/fy12osti/55658.pdf. National Renewable Energy Laboratory. Coca-Cola Refreshments Class 8 Diesel Electric Hybrid Tractor Evaluation: 13-Month Final Report. 2012. Report prepared for the DOE Advanced Vehicle Testing Activity. Retrieved from http://www.nrel.gov/docs/fy12osti/53502.pdf. Tioga Group, Inc., CDM Smith, and R. G. Little. Draft Final Report from NCFRP Project 34, âEvaluating Alter- natives for Landside Transport of Ocean Containers.â June 2014. (Note: final report published in 2015 as NCFRP Report 34: Evaluating Alternatives for Landside Transport of Ocean Containers, http://www.trb.org/ Publications/Blurbs/172637.aspx). Transportation Research Board, Board on Energy and Environmental Systems. Technologies and Approaches to Reducing Fuel Consumption of Medium- and Heavy-Duty Vehicles. Transportation Research Board of the National Academies, Washington, D.C., 2010. United States Department of Energy (U.S. DOE), Energy Efficiency & Renewable Energy. Clean Cities Guide to Alternative and Advanced Medium- and Heavy-Duty Vehicles. 2013. Retrieved from http://www.afdc.energy. gov/uploads/publication/medium_heavy_duty_guide.pdf.
Clean Truck Strategies 7 2.3 Alternative Fuels Besides electricity, a variety of liquid and gaseous fuels can replace conventional diesel or gasoline to power trucks (see Table 3). These include CNG, LNG, biodiesel, renewable diesel, and propane. â¢ CNG. Natural gas has a high octane number, which makes it suitable for spark ignition engines. Natural gas can be used in spark ignition engines with only changes to the fuel system to meter a gas instead of a liquid. For heavy-duty applications, natural gas requires conversion to a spark ignition engine or use of high-pressure direct injection in a compres- sion ignition (diesel) cycle. CNG is stored on board a vehicle in cylinders pressurized at 3,000 to 3,600 pounds per square inch (psi). Strategy Applicability Fuel and Emissions Reduction Cost per Truck AvailabilityFuel/GHGs PM NOx VOC CNG All heavy trucks; most suitable for short haul or regional 10%â20% GHG reduction 65+% reduction (renewable) Limited (but no DPM) 15%â 50% Limited Incremental truck cost from $12,000 (Class 3) to $75,000 (Class 8) Available for several truck sizes and applications LNG All heavy trucks; most suitable for long haul 10%â20% GHG reduction (fossil) 65+% reduction (renewable) Limited (but no DPM) 15%â 50% Limited Incremental truck cost of $75,000 (Class 8) Generally limited to Classes 7â8 Biodiesel (B20) All diesel trucks 2%â16% GHG reduction 3% 1% increase 3% Minimal truck cost; fuel cost slightly more than diesel Widely available in most states Biodiesel (B100) All diesel trucks (with modiï¬cation) 10%â80% GHG reduction 16% 2% increase 16% Some truck modiï¬cation costs; fuel cost slightly more than diesel Widely available in most states Renewable diesel (R100) All diesel trucks 50%â70% GHG reduction 20% none 20% No truck cost; fuel cost estimated at 20% more than diesel Very limited; expected growth is signiï¬cant LPG Medium-duty (spark ignition) applications 20% GHG reduction 70% 50% None Vehicle conversions cost $12,000; fuel is typically a discount compared to diesel Limited to original equipment manufacturer LPG vehicles; gasoline engines can be converted to LPG Table 3. Summary of alternative fuel strategies.
8 Guide to Deploying Clean Truck Freight Strategies â¢ LNG. Recent advances in tank storage capacity and fast-fill refueling technology for LNG have coupled with the surging supply of domestic natural gas to inject LNG as a serious option for long-haul trucking. The higher energy density and onboard storage capacity of LNG have made it a more appealing option for some trucking fleets. Purifying natural gas and super- cooling it to â260Â°F creates LNG. Because it must be kept at cold temperatures, LNG is stored in double-walled, vacuum-insulated pressure vessels. Note that renewable natural gas (RNG), derived from biomass or other renewable resources, is a drop-in replacement for natural gas used in transportation applications that reduce the emissions related to the upstream portion of the fuel life cycleânamely, collection of a feedstock, delivery to a processing facility for biomass-to-gas conversion, gas conditioning, compression, and injection into a pipeline. RNG is typically produced via either (a) anaerobic digestion or (b) thermal gasification. The most common source for RNG today is from anaerobic digestion, namely at landfills; however, other sources include wastewater treatment plants and animal manure (e.g., from dairies). For thermal gasification, the feedstocks can be agricul- tural residues, forestry and forest product residue, energy crops, and municipal solid waste. In California, for instance, through a combination of incentives from the federal Renewable Fuel Standard (RFS2; with a currency known as Renewable Identification Numbers, or RINs) and Californiaâs Low Carbon Fuel Standard, an estimated 50 million diesel gallon equivalents were consumed in natural gas vehicles. â¢ Biodiesel. Biodiesel is a renewable fuel made by reacting animal or vegetable fats with alcohol. Approximately 70% of the nationâs biodiesel is produced in the Midwest, where soybean oil is the dominant biodiesel feedstock. Most biodiesel is used in low-level blends, usually as 5% or 20% biodiesel blended with conventional diesel (referred to as B5 or B20, respectively). Pure biodiesel (B100) can be used in some truck engines with modifications. â¢ Renewable diesel. Renewable diesel is interchangeable with conventional diesel and does not have any blending limitations; it can be transported via pipeline, stored in the same facilities as diesel, and used without volume constraints in vehicle applications. â¢ Propane. Propane, or liquefied propane gas (LPG), is a well-developed engine technology. LPG is suitable for spark ignition engines. Other alternative fuels that were identified are ethanol and dimethyl ether (DME). Nearly all gasoline sold in the United States contains 10% ethanol. High-level ethanol blends (E85) can be used in some spark ignition engines for light freight trucks (Class 3 and 4); however, the emissions benefits of using E85 in freight trucks are negligible, and the commercial offerings are limited. DME has properties similar to propane and can be used in diesel engines with modification. However, DME currently has very limited availability. 2.3.1 Bibliography for Assessing the Emissions and Fuel Impacts of Alternative Fuels Durbin, T. D., J. W. Miller, K. Johnson, M. Hajbabaei, N. Y. Kado, R, Kobayashi, X. Liu, et al. CARB Assessment of the Emissions from the Use of Biodiesel as a Motor Vehicle Fuel in California Biodiesel Characterization and NOx Mitigation Study. 2011. ICF International. Alternative Fuels for Air Quality Implementation Planning. Prepared for the Metropolitan Energy Center, July 2014. Available at http://www.metroenergy.org. Karavalakis, G., et al. CARB Comprehensive B5/B10 Biodiesel Blends Heavy-Duty Engine Dynamometer Testing. 2014. Oregon Department of Environmental Quality. Biodiesel and Underground Storage Tank Systems. Retrieved from http://www.deq.state.or.us/lq/pubs/factsheets/tanks/ust/BiodieselUSTSystems.pdf. Petroleum Equipment Institute. UST Component Compatibility Library. http://www.pei.org/ust-component- compatibility-library.
Clean Truck Strategies 9 West Virginia University. In-Use Emissions Testing and Demonstration of Retrofit Technology for Control of On-Road Heavy-Duty Engines. 2014. Yanowitz, J., and R. L. McCormick. Effect of Biodiesel Blends on North American Heavy-Duty Diesel Engine Emissions. European Journal of Lipid Science and Technology 111, No. 8. 2009, pp. 763â772. 2.4 Vehicle Technologies â Targeting Fuel Efficiency Numerous improvements to truck tractors and trailers can improve fuel efficiency by reduc- ing the energy lost to aerodynamic drag, rolling resistance, auxiliary loads, idling, and other factors. All of these technologies are available today, and many are already employed by industry leaders. 2.4.1 Tractor-Trailer Technologies to Reduce Aerodynamic Drag Aerodynamic drag accounts for over 50% of the energy losses for a truck and tends to increase by the square of truck speed. Thus, aerodynamic devices are more suitable for long-haul trucks than for stop-and-go delivery trucks. Various aerodynamic devices can be used to reduce drag on tractors and trailers (see Table 4). Most of the strategies described here and shown in Figure 1 are commonly used in the trucking industry today. â¢ Boat tail. Reduces aerodynamic drag using a tapering protrusion mounted on the rear of a truck or trailer. â¢ Tractor gap fairing. Reduces the gap between the tractor and the trailer, reducing aerodynamic drag and improving the fuel economy of the vehicle. â¢ Roof fairings. Improve the flow of air over and around a tractor trailer, reducing aerodynamic drag and increasing fuel efficiency. Strategy Applicability Fuel and Emissions Reductiona Cost per Truck AvailabilityFuel/GHGs PM NOx VOC Boat tail Class 8 long haul 1%â2% n/a n/a n/a $2,800â $3,100 Widely available Tractor gap fairing Class 8 long haul (widely used today) 1%â2% n/a n/a n/a $300â$400 Widely available Roof fairings Class 8 (widely used today) 3%â6% n/a n/a n/a $1,000 day cab; $1,500 sleeper cab Widely available Tractor side fairings Class 8 (widely used today) 1%â2% n/a n/a n/a $360â$2,200 Widely available Trailer side skirts Class 8 long haul 3%â6% n/a n/a n/a $1,600â $2,200 per trailer Widely available Trailer gap fairings Class 8 long haul 1%â2% n/a n/a n/a $850 Widely available aFuel economy improvements at 65 mph. Benefits of device combinations are not additive, with full use of aerodynamic devices providing approximately 5%â10% fuel economy improvement over trucks with no aerodynamic devices. Criteria pollutant emissions will typically decline with fuel reduction, but the magnitude of the reduction is not well understood. Table 4. Summary of tractor-trailer technologies to reduce aerodynamic drag.
10 Guide to Deploying Clean Truck Freight Strategies â¢ Tractor side fairings. Extend downward from the base of the cab between the wheels of the tractor, covering the open space and streamlining the fuel tank(s). â¢ Trailer side skirts. Extend down from the bottom of the trailer to cover part of the open space between the tractor and the rear wheels, improving airflow around the trailer and reducing drag. â¢ Trailer gap fairings. Usually rounded additions to the sides and/or top of the front of the trailer that reduce the gap between the tractor and trailer. 2.4.2 Tires â Low Rolling Resistance and Single Wide Energy lost due to resistance or friction at the point where tires meet the road can have an impact on fuel economy of trucks, especially tractor trailers, which simply have more tires. The literature review focuses specifically on low rolling resistance tires and wide-base single (WBS) tires (see Table 5). â¢ Low rolling resistance tires. These tires minimize energy lost as heat as the tire rolls; they are characterized by axle position (i.e., steer, drive, or trailer). â¢ WBS tires. These replace two thinner tires, typically on the trailer. 2.4.3 Tire Pressure Systems Proper tire inflation is a critical element that fleet managers consider when they seek to opti- mize performance. Factors to consider include fuel economy, maintenance, tire wear, and driver satisfaction/comfort. Tire pressure systems (see Table 6) are designed to overcome a variety of causes of tire underinflation. Technologies include: â¢ Tire pressure monitoring system. Provides direct measurement of tire pressure; some tech- nologies also include temperature readings. Users establish a preset pressure target; when the pressure drops below this threshold, the driver and/or maintenance staff are alerted. Figure 1. Aerodynamic devices.
Clean Truck Strategies 11 â¢ Automatic tire inflation system. Monitors tire pressure relative to a preset target and re-inflates tires whenever the detected pressure is below the target level. The driver is typically alerted to the re-inflation, but the system does not report actual tire pressure. Re-inflation occurs via on-vehicle compressed-air tanks or air drawn directly from surrounding environment via a self-contained pump. â¢ Dual-tire equalizer. Monitors the pressure in both tires of a dual-tire assembly, with a hose connection to each tire valve stem. When pressure levels between the tires do not match, the system will bring the two tires to the same pressure level. No air is added or removed by the equalizer unit; if air loss continues, the leaking tire is isolated, and a visual signal is sent to the driver. Strategy Applicability Fuel and Emissions Reductiona Cost per Truck AvailabilityFuel/GHGs PM NOx VOC Low rolling resistance tires All trucks; focus on Classes 6â8 2%â10% n/a n/a n/a n/a Widely available for Class 8; limited availability for Classes 3â6 WBS tires Classes 5â8 2%â12% n/a n/a n/a $130 less than standard tire purchase Widely available aCriteria pollutant emissions will typically decline with fuel reduction, but the magnitude of the reduction is not well understood. Table 5. Summary of low rolling resistance and single-wide tire strategies. Strategy Applicability Fuel and Emissions Reductiona Cost per Truck Availability Fuel/GHGs PM NOx VOC Tire pressure monitoring systems Classes 6-8 0.5%â1.0% n/a n/a n/a $750â $1,225 Widely available Automatic tire inï¬ation systems Classes 6-8 0.5%â1.0% n/a n/a n/a $1,000 Widely available Dual-tire equalizers Classes 6-8 0.5%â1.0% n/a n/a n/a n/a Widely available Central tire inï¬ation systems Classes 6-8; typically intended for oï¬-road or military truck applications 0.5%â1.0% n/a n/a n/a n/a Widely available Passive pressure containment approaches Classes 6-8 0.5%â1.0% n/a n/a n/a n/a Widely available aFuel economy improvements at 65 mph. Benefits of device combinations are not additive, with full use of aerodynamic devices providing approximately 5%â10% fuel economy improvement over trucks with no aerodynamic devices. Criteria pollutant emissions will typically decline with fuel reduction, but the magnitude of the reduction is not well understood. Table 6. Summary of tire pressure systems.
12 Guide to Deploying Clean Truck Freight Strategies â¢ Central tire inflation system. Similar to automatic tire inflation systems, but the driver can select the target pressure from an in-cab display, thereby providing the driver the flex- ibility of increasing/decreasing tire inflation depending on the operating conditions of the vehicle. â¢ Passive pressure containment approaches. Include technologies capable of preventing tire pressure loss. These options include using nitrogen as an inflation medium, using built-in sealant layers, and aftermarket sealants. 2.4.4 Idle-Reduction Technologies Generally, truck drivers report idling from 1 to 10 hours per day. The ATA estimates that truck drivers average about 6 hours per day of idling time. The researchers identified several idle-reduction technologies: â¢ Fuel-operated heaters. Cab/bunk heaters that supply warm air directly from a small com- bustion flame to a heat exchanger, as opposed to using the primary engine. This is a simple heating solution that can also be designed to include cooling options, if necessary. â¢ Auxiliary power units (APUs). Portable vehicle-mounted systems that provide power for climate control and electrical devices when the engine is shut off. APUs are typically pow- ered by either a small diesel combustion engine and generator or batteries (external or internal). â¢ Auto start/stop systems. Electric-powered systems that automatically shut down the main engine when idling by monitoring cab and engine temperature. The system also restarts the engine when needed based on a set time period or temperature. Cab heating and cooling are provided when the engine cycle is on, but not when it is off. Although an electric system, no additional power is able to be used for other loads. â¢ Vehicle electrification. Systems that supply electricity for hotel loads through an inverter and battery charger that transforms DC power stored in vehicle batteries to 120 V alternating current (AC). Electricity can also be generated via roof-mounted solar photovoltaic panels to directly power electrical systems or store in batteries. â¢ Shore power. Onboard equipment that allows vehicles to plug into outlets at truck stops to power climate control systems and for other electrical needs. Requires that trucks be equipped with an inverter, plug-in hardware, and other electrical equipment, such as an electric heating, ventilation, and air-conditioning (HVAC) system. Anecdotal evidence from some trucking companies indicates that they have been able to reduce idling time by up to 50% in some cases; however, there is limited information regarding actual tracking and measuring the emissions benefits of idle-reduction technologies. Table 7 includes a range of emission factors for idling combined with the results from a 2009 American Transportation Research Institute (ATRI) report (Tunnell, 2009) regarding the implementation of APU idle-reduction technologies. 2.4.5 Bibliography for Fuel and Emissions Impacts of Vehicle Technologies ATRI. Demonstration of Integrated Mobile Idle Reduction Solutions. Final Report. 2009. Prepared for the U.S. Environmental Protection Agency Truck Engine Idle Reduction Technology Demonstration Program. Bachman, L. J., A. Erb, and C. L. Bynum. Effect of Single Wide Tires and Trailer Aerodynamics on Fuel Economy and NOx Emissions of Class 8 Line-Haul Tractor-Trailers. Presented at the Society of Automotive Engineers Commercial Vehicle Engineering Conference, Detroit, Michigan, 2005. Bradley, C., S. Nelson, and Michelin Tire North America. Truck Tires and Rolling Resistance. Presentation to the National Research Council Committee to Assess Fuel Economy Technologies for Medium- and Heavy-Duty Vehicles, February 4, 2009, Washington, D.C.
Clean Truck Strategies 13 CARB. Appendix E: Alternatives to Primary Engine Idling. Retrieved from http://www.arb.ca.gov/regact/idling/ isorappe.doc. Cooper, K. R. Truck Aerodynamics Reborn â Lessons from the Past. SAE Technical Paper 2003-01-3376, 2003. Curry, T., I. Liberman, L. Hoffman-Andreas, and D. Lowell. Reducing Aerodynamic Drag and Rolling Resistance from Heavy-Duty Trucks: Summary of Available Technologies and Applicability to Chinese Trucks. 2012. Prepared for the International Council on Clean Transportation. Gereffi, G., and K. Dubay. Auxiliary Power Units: Reducing Carbon Emissions by Eliminating Idling in Heavy- Duty Trucks. Chapter 3 of Manufacturing Climate Solutions: Carbon-Reducing Technologies and U.S. Jobs. Center on Globalization, Governance, & Competitiveness, Duke University, 2008. Federal Motor Carrier Safety Administration. Tire Pressure Monitoring and Maintenance Systems Performance Report. Report No. FMCSA-PSV-07-001. Washington, D.C.: U.S. Department of Transportation, 2007. Conducted by Booz-Allen-Hamilton, Inc., and Fisher Fleet Tire Consulting. Grygier, P. A., S. Daniel, Jr., R. L. Hoover, and T. R. Van Buskirk. Tire Pressure Monitoring System Tests for Medium and Heavy Trucks and Buses. Report No. DOT HS 811 314. Washington, D.C.: National Highway Traffic Safety Administration, June 2010. International Council on Clean Transportation (ICCT). Costs and Adoption Rates of Fuel-Saving Technologies for Trailers in North America On-Road Freight Sector. 2014. Retrieved from http://nacfe.org/wp-content/ uploads/2014/03/ICCT_trailer-tech-costs_20140218.pdf. North American Council for Freight Efficiency (NACFE). Executive ReportâWide Base Tires. 2010. NACFE. Confidence Report: Idle Reduction Solutions. 2014. Retrieved from http://www.carbonwarroom.com/ sites/default/files/reports/Idle-Reduction_Confidence_Report.pdf. Routhier, B. Wide-Base Tires Fleet Experiences. Presented at the International Workshop on the Use of Wide-Base Tires, Federal Highway Administration, Turner-Fairbank Highway Research Center, 2007. Tunnell, M. Demonstration of Integrated Mobile Idle Reduction Solutions. ATRI. August 2009. 2.5 Operational Strategies This category covers a wide range of approaches that enable trucks to operate more efficiently by reducing travel, reducing idling, or reducing inefficient engine operations such as those related to high speeds or congested driving conditions (see Table 8). Strategies include: â¢ Routing software. Onboard GPS and communication equipment that monitors the opera- tion of fleets to ensure that vehicles use the most efficient routes and maintain schedules. Use of this type of software can result in a reduction in empty mileage and VMT, although route Strategy Applicability Fuel and Emissions Reductiona Cost per Truck AvailabilityFuel/GHGs PM NOx VOC Fuel-operated heaters Class 8 3%â12% 1%â 11% 3%â 12% 1%â 11% $900â$1,500 Widely available Auxiliary power units Class 8 30%â60% 1%â 11% 3%â 12% 1%â 11% $2,000â $12,000; depending on power source Widely available Auto start/stop systems Class 8 30%â50% 30%â 50% 30%â 50% 30â50% $1,500â $2,500 Widely available Vehicle electriï¬cation Class 8 100% 100% 100% 100% n/a Widely available Shore power Class 8 100% 100% 100% 100% n/a, varies Widely available Note: Some data adapted from Tunnell 2009. aReductions listed are relative to high-speed idle during extended idle periods. Table 7. Summary of idle-reduction strategies.
14 Guide to Deploying Clean Truck Freight Strategies optimization is constrained to some extent by truck route restrictions and weight limits for bridges. In addition to optimizing route plans, carriers can improve fuel efficiency by reduc- ing vehicle miles driven that do not conform to planned routes. â¢ Engine governors. Onboard systems that limit vehicle speed. Truck power requirements and fuel use tend to increase in a nonlinear manner above 40 mph, so limiting top highway speeds is a particularly effective way to save fuel. For this reason, and for safety benefits, nearly all large carriers limit the top speed of their trucks using engine governors. Limits are typically in the range of 60 to 68 mph. Strategy Applicability Fuel and Emissions Reduction Cost per Truck Availability Fuel/GHGs PM NOx VOC Routing software Classes 4â8 1%â10% n/a n/a n/a $400â $10,000 Widely available Engine governors Classes 6â8 0.1 mpg increase for every 1-mph reduction n/a n/a n/a $1,000â $1,500 Widely available Truck-stop electriï¬cation (oï¬-board technologies) Class 8 long haul 36%â64% for APU; 74%â80% for shore power 10%â50% for APU; 93% for shore power 80%â90% for APU; 98% for shore power n/a $1,700â $3,500 Limited availability Eï¬cient truck refrigeration units Classes 6â8 15% n/a n/a n/a 10% more than standard diesel model Limited availability Loading and packing techniques Classes 6â8 15% for turn loading n/a n/a n/a n/a Available; limited use Gate appointment systems Class 7â8 drayage trucks Varies based on system conï¬guration and level of stakeholder buy-in n/a n/a n/a n/a Available; limited use Oï¬-peak incentives Class 7â8 drayage trucks n/a n/a n/a n/a n/a Available; limited use Chassis pools Class 7â8 drayage trucks n/a n/a n/a n/a n/a Available; limited use Virtual container yard Class 7â8 drayage trucks Varies; 15% VMT reduction for each street turn n/a Varies; 300g reduction for each street turn n/a Varies, Port of Los Angeles reported $168,000 per year Available; limited use Table 8. Summary of operational strategies.
Clean Truck Strategies 15 â¢ Truck-stop electrification (off-board technologies). Systems that allow drivers to plug in their vehicles at truck stops to power heaters, air conditioners, marker lights, and other acces- sories. Trucks need to be equipped with the internal wiring, inverter system, and HVAC sys- tem necessary to take advantage of external power. This type of system is sometimes referred to as âshore power,â reflecting its common use in marine applications. Advanced truck-stop electrification, such as the service offered by IdleAire Technologies, can provide heating and cooling from an external source. â¢ Efficient truck refrigeration units. Electrical standby equipment for refrigerated cargo that allows trucks to be plugged in when stationary, increasing the energy efficiency of the units. â¢ Loading and packing techniques. Specific loading and packing strategies that increase the efficiency of cargo movement. Strategies depend on the freight being transported, including the dimensions of the parcel units, the type of packaging, and its strength/fragility. Examples include maximizing load volume using software tools or loading consultants, increasing the number of loaded pallets through a pin-wheeling packing technique, and increasing loads by using thinner aluminum plate-wall trailers. â¢ Gate appointment systems. Systems that limit the time window in which drayage trucks can access the port based on the capacity of the equipment in the yard. Appointment windows reduce idling emissions and allow for predictable workloads and better resource scheduling. â¢ Off-peak incentives. Programs or incentives used by port operators to shift vehicles from congested to uncongested facilities or time periods in order to reduce idling. â¢ Chassis pools. A system in which different ocean carriers combine resources and use the same pool of freight transport equipment, alleviating demand fluctuations, and increasing chassis utilization at ports. â¢ Virtual container yard. An Internet-based system that facilitates coordination between ship- pers and receivers so that containers can be filled with export cargo before returning empty to the ports. Matching empty containers with shippers can eliminate truck trips and associated emissions. 2.5.1 Bibliography for Fuel and Emissions Impacts of Operational Strategies Cambridge Systematics. Port Truck Trip Reduction Strategies. Final Report. 2005. Prepared for the Port of Long Beach. CPCS Transcom Limited. NCFRP Report 20: Guidebook for Assessing Evolving International Container Chassis Supply Models. Transportation Research Board of the National Academies, Washington, D.C., 2012. Frey, H. C., and P. Y. Kuo. âReal-World Energy Use and Emission Rates for Idling Long-Haul Truck Engines and Selected Idle Reduction Technologies.â Journal of the Air & Waste Management Association, 59(7):857â864. July 2009. Retrieved from http://www.cte.ncsu.edu/eeconference/sessions/documents/63-1_Frey.pdf. Giuliano, G., and T. OâBrien. âResponding to Increasing Port-Related Freight Volumes: Lessons from Los Angeles/Long Beach and other US ports and Hinterlands, in Port Competition and Hinterland Con- nections.â Round Table 143, Transport Research Center, Organization for Economic Cooperation and Development, 2009. Gladstein, Neandross, & Associates. Moving California Forward: Zero- and Low-Emissions Goods Movement Path- ways. 2013. Prepared for the California Cleaner Freight Coalition. Retrieved from http://www.ucsusa.org/ sites/default/files/legacy/assets/documents/clean_vehicles/Moving-California-Forward-Report.PDF. ICF International. Opportunities to Reduce Greenhouse Gas Emissions from Trucking. 2009. Report prepared for the Environmental Defense Fund. New York State Energy Research and Development Authority (NYSERDA). Electric-Powered Trailer Refrigera- tion Unit Demonstration. 2007. Prepared by Shurepower LLC for NYSERDA and the U.S. EPA SmartWay Transport Partnership. Retrieved from http://www.shorepower.com/adeq-nyserda-final-report.pdf. Oak Ridge National Laboratory. Vehicle Technologies Market Report. 2013. Retrieved from http://cta.ornl.gov/ vtmarketreport/pdf/2013_vtmarketreport_full_doc.pdf. Transport Canada. Terminal Appointment System Study. 2006. Retrieved from http://www.tc.gc.ca/media/ documents/policy/14570e.pdf.
16 Guide to Deploying Clean Truck Freight Strategies Transportation Research Board, Board on Energy and Environmental Systems. Technologies and Approaches to Reducing Fuel Consumption of Medium- and Heavy-Duty Vehicles. Transportation Research Board of the National Academies, Washington, D.C., 2010. 2.6 Clean Truck Corridor Infrastructure Public agencies in Southern California and elsewhere have taken steps to explore infrastructure that would enable the operation of zero-emission trucks in freight corridors. Southern California will require large reductions in NOx emissions to meet the federal ozone standard by the required date of 2023. Communities near the ports of Los Angeles and Long Beach bear the brunt of envi- ronmental impacts from truck activity around the ports. And full-battery-electric Class 8 trucks with the range and performance to operate on the regionâs freeways are not expected to be com- mercially available for at least a decade and probably longer. Thus, this infrastructure has been seen as a way to accelerate deployment of battery-electric trucks, particularly those serving the ports, and act as a bridge technology until battery-electric trucks can operate independently throughout the region. Technologies in this category include (see also Table 9): â¢ Overhead catenary. Systems that connect vehicles to overhead electricity lines using a vehicle component known as a pantograph. While connected to the wire, the truck operates as an electric vehicle, providing reduced tailpipe emissions and other benefits. This system is similar to catenary systems currently used by transit trolleybuses and streetcars in a number of cities. Catenary systems that support heavy-duty trucks have been demonstrated in Europe by Siemens Mobility. Strategy Applicability Fuel and Emissions Reduction Cost Availability Fuel/GHGsa PM NOx VOC Overhead catenary Classes 7-8 20% 80% 100% 100% 100% Infrastructure cost of $1.3â $6 million per mile Not currently availableâstill in the development, testing, and pilot phase Linear synchronous motors (in roadway) Classes 7-8 20% 80% 100% 100% 100% n/a Not currently available In-road battery charging capabilities Classes 6-8 20% 80% 100% 100% 100% $2â$3 million based on transit bus system projects Not currently available In-road contact- less linear power Classes 6-8 20% 80% 100% 100% 100% $4.1â$6.2 million per mile for infrastructure Not currently available aThe GHG emissions attributable to electricity consumption in these clean truck corridor infrastructure strategies will depend on the mix of generation sources. In areas with higher percentages of coal-fired power plants, the emissions reductions will be smaller. In areas with higher percentages of renewable energy production, the emissions reductions will be greater. Table 9. Summary of clean truck corridor infrastructure.
Clean Truck Strategies 17 â¢ Linear synchronous motors (in roadway). Systems that propel vehicles using an electro- magnetic system embedded in a roadway. The embedded system uses an electrical current to generate oscillating magnetic fields. By coordinating the fields along the linear motor, a vehicle with a magnet placed in the field can be moved along the length of the motor. This propulsion technology has been used in a number of transportation systems for many years; linear motors have been most notably used for maglev trains. New electric trucks or existing trucks fitted with reaction plates or magnets would be moved along the roadway without the assistance of the onboard motor. â¢ In-road battery charging capabilities. Battery charging systems embedded in a roadway that provide more frequent charging opportunities for electric vehicles through induction charging. The charging system in the ground is connected to the grid and creates a mag- netic field that extends above the roadway. This field can induce an electrical current in a vehicle equipped with the proper receiving components when the vehicle is stopped above the charger. â¢ In-road contact-less linear power. Similar to the in-road battery charging strategy, vehi- cles are wirelessly powered through induction when they pass over charging infrastructure embedded in the roadway. Unlike in-road battery charging, this system would extend the electricity supply infrastructure over longer distances, allowing the vehicles overhead to be powered while in motion. This reduces the need for frequent stops at charging locations to replenish batteries. It also eliminates any physical link to power sources, such as pantographs connected to overhead catenary lines. 2.6.1 Bibliography for Assessing Costs and Impacts of Clean Truck Corridor Infrastructure Antlauf, W., F. G. Bernardeau, and K. C. Coates. âFast Track.â Civil Engineering, November 2004. Retrieved from http://namti.org/wp-content/uploads/Final-CE-Mag-Nov-2004.pdf. Den Boer, E., S. Aarnink, F. Kleiner, and J. Pagenkopf (Delft). Zero Emissions Trucks: An Overview of State-of-the- Art Technologies and Their Potential. 2013. Commissioned by ICCT. Retrieved from http://www.theicct.org/ sites/default/files/publications/CE_Delft_4841_Zero_emissions_trucks_Def.pdf. General Atomics. âMagneTruck: A New Concept for Zero-Emission Goods Movement.â Presented to Port of Los Angeles, March 18, 2009. Retrieved from http://www.magnetictransportsystems.com/documents/GA_ MagneTruck_03_18_09Final.pdf. Gladstein, Neandross, & Associates. Zero-Emission Catenary Hybrid Truck Market Study. 2012. Retrieved from http://www.transpowerusa.com/wordpress/wp-content/uploads/2012/06/ZETECH_Market_Study_ FINAL_2012_03_08.pdf. Suh, I. S. âApplication of Shaped Magnetic Field in Resonance (SMFIR) Technology to Future Urban Trans- portation.â CIRP Design Conference. 2011. Retrieved from http://koasas.kaist.ac.kr/bitstream/10203/23718/ 1/-CIRP-Design-2011-Paper34-Suh.pdf. Tanger, Reed. âTransrapid Maglev System.â Presentation. Retrieved from http://www.transportation.north western.edu/docs/2007/2007.03.28.Tanger.Presentation.pdf. Tioga Group, Inc., CDM Smith, and R. G. Little. Draft Final Report from NCFRP Project 34, âEvaluating Alter- natives for Landside Transport of Ocean Containers.â June 2014. (Note: final report published in 2015 as NCFRP Report 34: Evaluating Alternatives for Landside Transport of Ocean Containers, http://www.trb.org/ Publications/Blurbs/172637.aspx).