Idle reduction has become a huge topic of conversation, as it can contribute hugely to our environment. The rail and trucking industries have adopted several technologies to reduce idling time and to cut back on greenhouse gas emissions. Examples include railroads placing genset locomotives into service for switching and yard operations and the trucking industry utilizing auxiliary power units and electrified parking spaces to keep drivers comfortable during rest periods.
Since many locomotives do not require maximum horsepower all the time, Union Pacific investigated the development of a switching locomotive that would use modern off-road diesel engines that would be capable of providing the lower power required by typical switching locomotives while reducing fuel consumption and exhaust emissions. Instead of having one large conventional locomotive diesel engine operating at various speeds, multiple smaller diesel engines, running in combinations of 1, 2 or 3 engines, would be used to produce the required horsepower levels. The diesel engines, electrical generator, cooling system, and radiator would be placed in one compact module called a generator or “GenSet.”
A GenSet locomotive and its generator sets are computer controlled. One generator set is initially used when starting the locomotive. As the locomotive engineer goes to increasingly higher throttle settings, a second or third GenSet engine is quickly started and begins providing power. When that power demand is no longer needed, the second or third unit automatically shuts down. A GenSet locomotive also is equipped with Automatic Engine Stop Start (AESS) technology that shuts down the locomotive when it is not in use. Most importantly, emissions tests on GenSet locomotives found that the 80-90 percent reduction in exhaust emissions was practical and could be achieved.
A prototype 1400-horsepower GenSet was built for Union Pacific during 2005 and tested in Illinois and California. The prototype was powered by two generator sets, each with a 700-horsepower, ultra low-emissions off-road Cummins diesel engine that reduced nitrous oxide and particulate emissions by up to 80-90 percent, while using as much as 16 percent less fuel compared to other low-horsepower locomotives. The 16 percent less diesel fuel usage also translated into a minimum 16 percent reduction in greenhouse gases.
The research and development of GenSet locomotives has since expanded with companies such as Railpower Technologies, National Railway Equipment, MP-Wabtec introducing their own latest high horsepower models. Railpower Technologies offers three different models ranging from 1,400 to 2,000 horsepower that are powered by Deutz V-8 2015 Engines. National Railway Equipment has developed its N-ViroMotive GenSet locomotive that provides power in the range of 1,400 to 2,100 horsepower that will include advanced design diesel particulate filters that will reduce PM emissions to the lowest level ever achieved in a diesel-electric locomotive. Wabtec Corporation’s MPXpress locomotive is capable of delivering 3,600 horsepower.
The GenSet locomotives have helped dozens of companies across the United States and throughout the world reduce nitrous oxide and particulate matter emissions by 80 percent and reduce carbon dioxide emissions by 45 to 65 percent. Not only is the locomotive good for the environment, but its increased fuel efficiency is a crucial tool in reducing costs and decreasing dependence on foreign oil. The trucking industry has also adopted advanced technology to promote anti-idling measures. The most common auxiliary power unit (APU) for a commercial truck is a small diesel engine with its own cooling system, heating system, generator or alternator system, and air conditioning compressor, which is housed in an enclosure and mounted to one of the frame rails of a semi-truck. Other designs fully integrate the auxiliary cooling, heating, and electrical components throughout the chassis of the truck. These units are used to provide climate control and electrical power for the truck’s sleeper cab and engine block heater during downtime on the road.
In the United States, federal Department of Transportation regulations require 10 hours of rest for every 11 hours of driving. During these times, truck drivers often idle their engines to provide heat, light, and power for various comfort items. Although diesel engines are very efficient, it is financially and environmentally costly for these engines to idle. The auxiliary power unit is designed to eliminate these long idles. Since the generator engine is a fraction of the main engine’s displacement, it uses only a fraction of the fuel. Some models can run for an entire eight hours on one gallon of diesel fuel. The generator also powers the main engine’s block and fuel system heaters, so the main engine can be started easily right before departure if the APU is allowed to run for a period beforehand. An auxiliary power unit can save up to 20 gallons of fuel a day, and can extend the useful life of the main engine by around 100,000 miles, by reducing non-productive run time.
As an alternative to the diesel units, APUs using an auxiliary battery system or hydrogen fuel cells as a source of power have also been designed. Freightliner has developed a demonstration model of a fuel cell APU, which receives its energy from a tank of liquid hydrogen mounted to one of their Century Class S/T road tractors.
Some auxiliary power units can also use solar and wind power as an option for power generation that is stored in batteries for later use. Renewable energy APUs use the sun and wind for power instead of diesel fuel to produce power to operate air conditioning and heating and other semi truck accessories.
In addition to auxiliary power units, trucking companies can use an external power connection for their heating and cooling functions, thus eliminating fuel consumption during rest periods. Many truck stops provide electrical connections in their parking areas, also known as electrified parking spaces (EPS) or truck stop electrification (TSE). These systems can include electrical devices on-board the truck (dual system EPS) that simply plug-in or complete wayside units that supply all services for an hourly fee, through a window module (single system EPS). The module can be mounted on a pedestal or an overhead gantry. A more advanced service, offered by IdleAire Technologies Corporation, termed Advanced Travel Center electrification (ATE), includes heating and air conditioning, phone service, Internet connectivity, television, and 110-volt electrical outlets. The ATE services are delivered by a distinctive yellow tube that hooks into the door window of the truck.
Auxiliary power units and truck stop electrification has helped trucking companies across the United States reduce nitrous oxide, particulate matter, carbon dioxide emissions by a factor of 3 or more compared to idling. Not only are the technologies good for the environment, but the combined fuel efficiency is an effective tool in reducing costs and decreasing dependence on foreign oil.