Engine idle reduction was discussed in the National Research Council (NRC) Phase 2 report (NRC, 2012); this report provides a brief update. Engine idling, in sleeper tractors alone, uses 2 billion gallons of diesel fuel according to a recent study (NACFE, 2014). The engine is idled (1) while waiting in queues at weigh stations, toll booths, ports and depots, (2) to maintain temperature in the cab for the comfort of the driver both day and night, (3) to power electrical appliances such as refrigerators and microwave ovens, (4) to maintain the charge level of batteries, and (5) to maintain the temperature of the engine oil and fuel during cold weather. Unnecessary idling leads to increased fuel consumption as well as emissions of carbon dioxide (CO2), criteria pollutants, and noise. Reducing idling and associated fuel consumption can be avoided with idle reduction technologies, attention to policies affecting freight efficiency, and changes in driver behavior, e.g., turning off the engine when not needed. Over a decade ago, it was common for trucking companies to report idle time in excess of 50 percent. Fleets with good operations would often report 35 percent idle time, and a benchmark number was below 20 percent. Today, it is more common for these same fleets to report worst case numbers around 35 percent, and averages near 20 percent, with benchmark numbers suggesting as low as 5 percent (NACFE, 2013, 2014). Unfortunately, there is no specific and agreed-on method for determining idle time. The electronic control modules (ECMs) on the engines are the source of this information for fleets. How an individual engine manufacturer decides to calculate idle time varies. Some may exclude time waiting in traffic, while others do not. Some may exclude initial idle at start before the vehicle moves. Time limits are often used in the ECMs to differentiate between idle and nonidle operation of the engine.
California remains a leader in regulations related to idling. As noted by the California Air Resources Board (CARB), “pursuant to state regulation, operators of diesel-fueled trucks with a gross vehicle weight rating greater than 10,000 lb are not to idle for more than 5 minutes when stopped within California’s borders. As of January 1, 2008, this restriction also applies to sleeper berth trucks. Consequently, many operators are now required to use some form of idle reduction technology to provide cab comfort services during periods of sleep and rest” (CARB, 2014). Beginning in 2008, idling for more than 5 minutes on most commercial vehicles was allowed, but required a Certified Clean Idle sticker. According to CARB, a Certified Clean Idle label is for vehicles that use an engine that has been certified to an optional NOx idling emission standard of 30 g/hr.1 Additional information about California’s commercial vehicle idling regulations and idle reduction technologies are given by the California Environmental Protection Agency’s CARB (2013, 2014).
The clean idle engine reduces nitrogen oxide emissions compared to older engines, but still burns fuel. While these new, clean idle engines burn less fuel while idling than older engines, estimates for the amount of fuel burned while idling vary from about 0.13 gallons per hour for a diesel-powered auxiliary unit, to as much as 1 gallon per hour for the main engine at certain speeds (Curran et al., 2013; Detroit Diesel Corporation, n.d.). Engine manufacturers do not regularly include a specification for idling fuel consumption in their product literature.
Anti-idling regulations around the country have been driven by the need to reduce fuel use, emissions, and noise. A patchwork of regulations at the state and municipality level has been created. The National Idling Reduction Network News website run by the U.S. Department of Energy (DOE) is updated monthly with information on idling; Figure 6-1 is taken from the August 2014 issue. It shows the changes in coverage of idling regulations throughout the 50 states. Note that there are more areas with “jurisdictional” regulations than with statewide regulations.
FIGURE 6-1 Extent of truck idling regulations in the United States, 2004 and 2014. In 2014 there were idling regulations in 20 states and the District of Columbia, compared to 10 states and the District in 2004. There are now jurisdictional laws in 18 states compared to 8 in 2004. SOURCE: DOE (2014).
The North American Council on Freight Efficiency (NACFE) in conjunction with the Carbon War Room published a report on idle reduction technologies in 2014 (NACFE, 2014); this document provides an update on currently available products and technologies.
The current stated goals of the Partnership related to idle reduction were provided in a document in November 2014 (DOE, 2014). Compared to some of the other goals of the Partnership, these goals are general in nature rather than specific and time limited. The goals and some activities and accomplishments have been identified and are discussed below:
- Promote the incorporation of idle reduction (IR) equipment on new trucks as fuel-saving devices, just as they are so identified by the DOE SuperTruck Initiative. The four SuperTruck teams have all decided to use battery-powered auxiliary power units (APUs) for the energy needs during the rest portions of the 24-hr cycle of the program. The Partnership suggests it would be worthwhile to conduct a comparison of performance and lifetime costs of battery-powered APUs to those of diesel-fueled APUs and to publish the results in the IdleBox2 web tool run by Argonne National Laboratory.
- Establish a nationwide multimode IR education program. Argonne National Laboratory created IdleBox, an electronic resource of idling reduction materials. It includes a calculator that fleets can use to assess idle reduction needs. IdleBase is a component of IdleBox that provides a compendium of every state’s idling reduction laws. ANL also publishes the online monthly National Idling Reduction Network News for DOE, which contains important information on funding sources, changes in regulations, and updates to weight exemptions for APUs.
- Work with OEM truck manufacturers to obtain data on the number of new trucks being ordered with IR options. Because many vehicle original equipment manfacturers (OEMs) consider information on sales data to be confidential and proprietary, the Partnership was unable to get complete data for this goal. Figure 6-2 shows the data reported by some manufacturers. The Auto Engine Start/Stop item is a feature available that automatically starts and runs the engine for a limited amount of time if the cab temperature drops, the engine oil temperature drops, or the battery charge, as measured by voltage, gets low.
- Conduct a fleet survey to gather data on the amount of in-use idling hours that are accumulated by each type of heavy-duty vehicle. This goal has not been met for a combination of reasons such as lack of funding and need for Office of Management and Budget (OMB) approval for surveys involving more than 10 people. Alternatives based on information from the National Renewable Energy Laboratory’s (NREL’s) Fleet DNA project and a revival of the Vehicle Inventory and Use Survey (VIUS) have been discussed.
- Analyze data from the EPA SmartWay Transport Partnership to measure fuel savings and emissions reductions associated with the various types of IR equipment available. No information was made available with which to evaluate this goal.
- Develop improved IR systems to minimize fuel required, cost, and weight to meet hotel functions in sleeper cabs. The SuperTruck program; the CoolCab Thermal Load project; the CoolCalc heating, ventilation, and air conditioning (HVAC) model; and STEP
2 See IdleBox Toolkit for Idle-Reduction Projects at http://www1.eere.energy.gov/cleancities/toolbox/idlebox.html. Accessed February 18, 2015.
3 G. Keller, ANL. “Update on Idling Reduction Activities,” presentation to the committee, September 4, 2014, and D. Anderson, “Vehicle Systems Simulation and Testing,” presentation to the committee on September 3, 2014.
FIGURE 6-2 Typical order rate for idle reduction devices in new trucks. SOURCE: DOE (2014).
- are activities that support this goal.3 Each of these activities is briefly discussed below.
The 21st Century Truck Partnership (21CTP) has difficulty identifying specific projects and funding devoted to all idle reduction activities and projects. Idle reduction activities are found in the SuperTruck program, the Clean Cities program, and elsewhere. In a presentation to the committee on September 3, 2014, “Update on Idling Reduction Activities,” G. Keller identified four specific projects (CoolCab, CoolCalc, the ShorePower Truck Electrification Project [STEP], and SuperTruck) as being R&D projects in this area. Funding information was reported for the first two projects, CoolCab and CoolCalc, as $575,000 in 2012, $1,200,000 in 2013, and $500,000 in 2014. The January 2015 issue of the National Idling Reduction Network News reports up to $211 million having been spent on idle reduction activities in the “last decade” by the Partnership organizations, the private sector, and the states.
All four teams for the SuperTruck program (Daimler, Volvo, Cummins-Peterbilt, and Navistar) have chosen battery-powered APUs (see Chapter 8). For the Cummins-Peterbilt team, the NRC Phase 2 report recommended abandoning the solid oxide fuel cell (SOFC) approach for the APU (NRC, 2012). The team and the Partnership continued for a period of time with the SOFC approach but eventually stopped that effort because the SOFC approach was found to be heavier, more costly, and to take longer to warm up than specified in the goal. Currently it is using a battery-powered APU with a 13.2 kWh capacity lithium-ion pack and electrically controlled HVAC. The pack can be recharged in 6 hours of driving. Over the 24-hr duty cycle of the program, a 7 percent savings in fuel has been reported compared to the baseline chosen for the SuperTruck program.4 The Daimler team is using a hybrid drivetrain configuration that includes a lithium-ion battery pack and electrically controlled HVAC. To reduce the need to cool the cab, it is using solar reflective paint, similar to the CoolCab project. They are reporting a 3 percent fuel savings compared to the baseline chosen for the SuperTruck program.5 Volvo Trucks is also using a battery-powered APU and electrically controlled HVAC. It is in the process of installing solar panels to assist in charging.6 However, during a visit to Volvo, the committee learned that the solar panels would only be able to support the electrical load of a fan.
The CoolCab and CoolCalc projects at NREL are normally classified as thermal management projects by DOE. They have investigated advanced insulation technologies to reduce the load, the ability of different paints to better reflect sunlight, and techniques to cool the occupant rather than the whole cab. Reducing these thermal loads increases the potential for using battery-powered APUs rather than idling the engine. The energy balance for recharging the batteries while the vehicle is operating has not been reported.
An analytical HVAC system model and test methods called CoolCalc will be useful to further these investigations. The projects were expected to have been completed in 2015.
STEP, also referred to as Interstate Grid Electrification project ARRA VTO 70, is a separate project supported by American Recovery and Reinvestment Act (ARRA) funds. Fifty truck stops have been outfitted with electrical power outlets only, sufficient to support 1,252 vehicles. The build-out of the system took longer than anticipated owing to varying municipal regulations at the different sites as well as prolonged negotiations with some truck stop owners. The Cascade Sierra Solutions project was replaced by STEP in 2014. Data collection is under way and is reported by NREL. Utilization of the pedestals and electrical connections was reported as less than 20 percent in 2014 status reports. STEP provides only electrical power and does not provide for as many amenities for the driver as might be desired. For instance, IdleAir is a supplier providing HVAC externally, internet connectivity, satellite television, and 120-V electricity. Recently, Con-Way Truckload announced a dedicated IdleAir facility in its Laredo, Texas, facility (Owens and Bachman, 2014). A final report is due in 2015.
NRC Phase 2 Recommendation 6-1. DOE, EPA, and DOT should develop a consolidated list of the funding provided for the idle reduction projects, review the effectiveness of these projects, and formulate a coordinated and consistent plan to encourage the adoption of idle reduction technologies to meet the goal of reducing fuel use and emissions produced by idling engines by at least two-thirds by 2017. The EPA and DOT
should work to find incentives for states to promulgate uniform anti-idling regulations.
21CTP Response: Presently, the National Idling Reduction Network News publication reports the various sources for funding idling reduction programs culled from press releases. We agree that a consolidated listing of these projects would be useful. The recommendation calls for a more coordinated effort between the DOE, EPA, and DOT to maintain the momentum begun in the application of idling reduction (IR) technologies, and to ensure minimal overlap of these programs across agencies. Establishing a more structured approach to the introduction of IR devices would be conducive to introducing objective measures to monitor the effectiveness of these various programs. Further, we agree that achieving nationwide uniformity of anti-idling regulations needs to be accomplished soon, and that the EPA and DOT could be instrumental in developing incentives to states to pass such rules.
Committee Comment on Response to 6-1
The Partnership response, while supportive of the Phase 2 Recommendation 6-1, does not suggest action will be taken in this area. The Partnership was asked for and did provide some input on the idle reduction report of NACFE. In consideration of their goals in this area, more work should have been done apart from the SuperTruck program to accomplish idle reduction for current vehicles now in the field. Going forward, with the completion of the SuperTruck program, the Partnership will need to readdress its activities in this area.
NRC Phase 2 Recommendation 6-2. The DOE should conduct a study that includes wide ranges of truck models, ages, and fleets to determine payback periods for the range of commercially available add-on idle reduction systems. The DOE should continue to encourage the deployment of add-on idle reduction systems through communications to manufacturers and end users.
21CTP Response: The 21CTP agrees with NAS that it would be valuable for DOE and EPA to fund a comprehensive study to verify the performance and payback claims of add-on idle reduction systems across a variety of popular trucks and climate regions. Such a study would be extremely valuable to the trucking community in helping to identify the most cost-effective add-on systems to invest in for their particular applications. The DOE could share these study results with quarterly updates as an addendum to the National Idling Reduction Network News publication.
Committee Comment on Response to 6-2
While the Partnership agreed with Phase 2 Recommendation 6-2, there is no evidence that anything has been done that addresses this recommendation. The number of options available for anti-idle have increased, but their effectiveness is still a question. The report from the North American Council for Freight Efficiency provided a payback calculator, but more work among the Partnership, DOE, EPA and NACFE is needed to validate or refine this model.
NRC Phase 2 Recommendation 6-3. The DOE should reassess the viability of the Solid Oxide Fuel Cell (SOFC) APU, particularly for application to the SuperTruck program.
21CTP Response: The information presented during the 21CTP NAS review was based upon one of our initial A-Level prototype units. Since then, we have made significant progress and are now assembling our B-Level prototype units. These units should be capable of demonstrating the targeted goal of 35% efficiency and output of 3kW. On the SOFC stack, Delphi has completed more than 10,000 hours of durability testing. Additionally, we have accumulated thousands of hours of on-truck, real-work application data. We are scheduled to deliver a B-Level unit during Q1 ’12 to a national fleet for use on one of their regular in-service long haul trucks. Currently, our start-up time is ~2 hours. The 5-hour example reported on represented a given demonstration. Our goal is to be at operating temperature in under 1 hr. Current costs reflect laboratory built prototype units. Delphi is investing in production intent tooling to drive down overall unit cost. Funding to date has allowed Delphi, as well as other fuel cell developers, to move their products from concept design to real-world demonstrations. Congress has recently reinstated funding for SECA and other fuel cell programs. Delphi will use the re-funded SECA program to further improve the power output and durability of its SOFC stack.
Committee Comment on Response to 6-3
The Partnership rejected the Phase 2 Recommendation 6-3. Subsequently, the SOFC was eliminated from the plans of the SuperTruck teams (both Daimler Trucks North America and Cummins-Peterbilt explored this). At the International Automobile Association (IAA) show in September 2014, a diesel-fueled SOFC APU was on display; Eberspaecher is planning commercial introduction of SOFC APUs in Class 8 trucks in 2016-2017 (Eberspaecher, 2014). Activities for fuel cells continue at AVL and Volvo (Rechberger et al., 2013). Based on developments in Europe, there is a need to reevaluate the future of fuel cells for idle reduction and other auxiliary loads on commercial vehicles.
NRC Phase 2 Recommendation 6-4. The 21CTP should review and potentially revise its idle reduction plans and goals in view of the fact that the proposed 2017 fuel efficiency standards provide an incentive for the adoption of idle reduction technologies as a means for achieving these standards for Class 8 long-haul trucks with sleeper cabs.
21CTP Response: The 21CTP agrees that the EPA’s rulemaking to establish fuel efficiency standards for heavy-duty truck fleets provides an incentive to look beyond Class 8 long-haul trucks with sleeper cabs to other types of trucks for additional opportunities to apply idle reduction technologies. We feel that
a substantial improvement to the idle reduction goal would include support to establish a program to address the fuel wasted in work day idling of all types of vocational trucks.
Committee Comment on Response to 6-4
The Partnership response indicates agreement with the Phase 2 Recommendation 6-4, but no action has been taken in this area. As the Partnership looks beyond the SuperTruck program, the value of start/stop, battery-operated or fuel-cell operated booms on electric utility trucks, and options for heating and cooling without running the primary engine needs to be investigated.
NRC Phase 2 Recommendation 6-5. The 21CTP should revise its new idle reduction goals to include metrics, funding, and timing for the overall goal of reducing fuel use and emissions produced by idling engines. The associated “action items” should be supportive of these goals.
21CTP Response: The 21CTP agrees with the NAS recommendation that the inclusion of a progressive and measurable program for idle reduction goals development is needed along with the year-to-year funding necessary to develop data to enable such an approach.
Committee Comment on Response to 6-5
The response to the Phase 2 Recommendation 6-5 indicates agreement in this area but based on the reference to needed funding it would seem to lack signs of commitment.
Finding 6-1. Improvements have been made in reducing idle time for long haul trucks over the last 10 years. The growth of fleet management systems and efforts by the Partnership, DOE, EPA, and the California Air Resources Board (CARB) have helped fleets understand the impact and the methods available to reduce idle time. No consistent way to measure and track idle time has been found, since algorithms are independently determined by the developers of the software for engine controls and fleet management systems.
Finding 6-2. The Partnership has focused much of its effort on the SuperTruck program and made progress in highlighting the impact of idling by including a 24-hr cycle in its fuel use evaluation. The stated goals for data acquisition and data analysis have not been met.
Recommendation 6-1. The Partnership, in collaboration with EPA, the National Highway Traffic Safety Administration (NHTSA), and CARB should review the North American Council for Freight Efficiency (NACFE) payback calculator and establish a consistent way to measure and track idle time for both over-the-road and vocational vehicles. As a follow-on, the Partnership should run a program for field data acquisition and analysis, leveraging the resources of NACFE and its fleets.
Recommendation 6-2. As the Partnership looks beyond the SuperTruck program, the value of start/stop systems, battery-operated or fuel-cell operated auxiliary loads, and options for heating and cooling without running the primary engine should be investigated.
Recommendation 6-3. The Partnership should establish goals, specific plans, and funding to reduce the nation’s consumption of fuel for idle by over 50 percent by 2025. The baseline should be from the estimate the Partnership generates for total 2016 idle fuel usage based on information to be acquired from the field using DOE’s Fleet DNA project and working with fleets, industry associations, and vehicle OEMs.
CARB (California Environmental Protection Agency Air Resources Board). 2004. Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling. http://www.arb.ca.gov/msprog/truckidling/2485.pdf.
CARB. 2013. Facts about California’s Commercial Vehicle Idling Regulations. http://www.arb.ca.gov/msprog/truck-idling/factsheet.pdf.
CARB. 2014. Idle Reduction Technologies for Sleeper Berth Trucks. http://www.arb.ca.gov/msprog/cabcomfort/cabcomfort.htm.
Curran, S., K. Settles, and K. Keel-Blackmon. 2013. ORNL Operations Best Practices Guide: Idle Reduction. Oak Ridge National Laboratory Sustainable Campus Initiative. https://sustainability-ornl.org/documents/ORNL%20Idle%20Reduction%20Guide.pdf.
Detroit Diesel Corporation. n.d. Fuel Economy: Creating Optimal Performance. http://www.demanddetroit.com/pdf/performance/5927-3_DD_FuelEcon_FINAL.pdf.
DOE (U.S. Department of Energy). n.d. Vehicle Technologies Office: National Idling Reduction Network News. http://energy.gov/eere/vehicles/vehicle-technologies-office-national-idling-reduction-network-news.
DOE. 2014. 21CTP Idle Reduction Goal Status. Submitted to the NRC Committee for Review of the 21st Century Truck Partnership, Phase 3, November 17.
Eberspaecher. 2014. Eberspaecher at the IAA Commercial Vehicles 014: Diesel fuel-cell APU revolutionized energy management in the truck. Press release, July 17. https://www.eberspaecher.com/index.php?eID=download&file=fileadmin/data/corporatesite/presse/pressemitteilungen/2014_presse/pressemitteilungen/PR_IAA_CV_2014_preliminary_report.pdf.
NACFE (North American Council for Freight Efficiency). 2013. Anti Idling Technology Overview. http://nacfe.org/wp-content/uploads/2013/08/Trucking-Efficiency-Anti-Idling-Tech-Overview-072413.pdf.
NACFE. 2014. Confidence Report on Idle-Reduction Solutions. http://www.carbonwarroom.com/sites/default/files/reports/Idle-Reduction_Confidence_Report.pdf.
National Research Council (NRC). 2012. Review of the 21st Century Truck Partnership, Second Report. Washington, D.C.: The National Academies Press.
Owens, K., and K. Bachman. 2014. Con-way Truckload Opens Idle Air Facility at Laredo, Texas, Terminal. Con-way Press Release. http://www.con-way.com/en/about_con_way/newsroom/press_releases/Dec_2014/2014_dec_09.
Rechberger, J., A. Kaupert, C.G. Greisen, J. Hagerskans, and L. Blum. 2013. Fuel-cell APUs show promise for heavy-duty truck anti-idling. SAE Off-Highway Engineering Online. http://articles.sae.org/12659/.