The Six R's of Diesel Cleanup

Diesel-powered vehicles have long been efficient work horses in America and world wide. They will continue to play an economically critical role of moving people and goods. While new diesel engines show improvement, older diesels are highly polluting. They contribute significantly to respiratory diseases, cancer, heart disease, nervous system impairment and premature death¹. According to published studies, people who work in and around diesel vehicles, those living close to diesel “hot spots,” children riding diesel school buses, and the elderly are at greatest risk².

For these reasons, Ohio Green Fleets focuses particular attention on cleaning up and/or replacing diesel powered vehicles. Any individual cleanup action such as a retrofit device or cleaner fuel will make an impact. However, the greatest and most cost effective approach will be to develop and implement a comprehensive strategy, which we and others³ have called the “Six R’s of Diesel Cleanup.”

1. Reduce fuel use.

2. Refuel with cleaner fuels

3. Retrofit existing vehicles

4. Rebuild older diesel engines

5. Repower older diesel engines

6. Replace older diesels with newer engines

Reduce fuel use.

Reducing fuel use cuts fleet costs and all types of pollution. Diesel cleanup (or any cleanup) strategy always should begin with considering how to simply use less energy of any type. Diesel fuel use reduction strategies are often plentiful. Idle reduction is a necessary component of reducing fuel use.

According to the US Department of Energy, diesel trucks waste over 800 million gallons per year without even moving. Add buses, trains and other diesels vehicles to this equation and the amount is significantly greater. Diesel operators idle out of habit and necessity, but some idling can be eliminated by policy and education. Other idling practices can’t be eliminated without use of equipment or facilities. Understanding why a diesel vehicle is idling is the key to its effective elimination. For example, do vehicles idle over night to keep operators comfortable and to provide electrical power? An auxiliary power unit, bunk heater, or truck stop electrification facility may provide solutions. Do vehicles idle in cold weather to warm engines and other systems? Engine pre-heaters may eliminate the need for this cause for idling. Do vehicles idle to operate bucket trucks and other peripheral equipment? Do operators idle to keep warm while waiting or taking a lunch break? Still other technologies offer solutions. Or does idling occur simply based on myth or habit? Education and policy may be a partial answer.

The US Environmental Protection Agency's Smartway program is among numerous government and private sources of idling reduction technology, policy and educational information. Based on the high cost of diesel fuel today, idle reduction technologies and strategies usually offer quick and significant paybacks on costs. Aside from idle reduction, many other technologies offer fuel use reduction benefits. The right fits for any fleet depend on the vehicles and applications.

Refuel with cleaner fuels.

Next on the list of cleanup strategies is to consider using a cleaner-burning fuel in existing vehicles. For on-road diesels, ultra-low sulfur diesel is the standard and the cleanest petroleum-based fuel available. Off-road construction equipment, locomotives and other non-road construction vehicles use a higher sulfur diesel blend. Refueling options are good to consider next in the progression of the “Six R's” because these involve only changing fuels, not equipment. While these options may not necessarily save money, they are the most simple and straightforward to implement and have a significant positive impact on the environment.

Biodiesel: Biodiesel is made from domestic, renewable, non-petroleum sources, and is cleaner burning. Biodiesel is usually blended with petroleum diesel. It’s important to use biodiesel that meets high-quality standards and is blended and handled correctly. The levels of emissions reductions will depend on the percentage of biodiesel blended with petroleum diesel. Blended biodiesel performs well and reduces engine wear. Using it also supports our economy.

Ultra-Low Sulfur Diesel for Non-Road: In addition to biodiesel, off-road and locomotive fleet operators may choose to use ultra-low sulfur, the standard on-road diesel fuel. By doing so they will achieve modest emissions reductions and facilitate installation of certain diesel retrofit equipment that can only function with ULSD and/or biodiesel.

Retrofit existing vehicles.

Next on the progression of options should be retrofitting existing diesel engines with various types of emissions control equipment. Common types include diesel oxidation catalysts (DOCs), diesel particulate filters (DPF), diesel multi-stage filters (DMFs) and closed crankcase filtration systems.

While none of these technologies will save money for a fleet, all of them are fairly straightforward to install and operate. Diesel engine manufacturers themselves often offer these products and established dealer networks can provide installation or installation and operations advice. For example, Ohio Green Fleet sponsors Cummins-Emissions Solutions and Donaldson offer various retrofit technologies for diesel engines.

Significant information about retrofit technology exists from a variety of sources including the US EPA’s National Clean Diesel Campaign and Midwest Clean Diesel Initiative. These and various industry resources can help your fleet select the most appropriate technologies and products for your fleet based on the specific engines you have, their age, vehicle type, application and cost-benefit considerations. Clean Fuels Ohio, through the Ohio Green Fleets program along with many other national and state non-profit organizations, provide expertise on accessing grant resources and explaining the health benefits of various technologies.

Rebuild older diesel engines.

Diesel engines, especially large ones, represent a large capital investment. Because of their high cost and durability, they often are rebuilt and reinstalled in existing or new vehicles. Also, pollution levels from diesels, like other internal combustion engines, increase as the engines age. Rebuilding diesel engines, on a normal or accelerated schedule, provides an opportunity to incorporate new technologies to significantly cut emissions.

Typically grants may be available for diesel engine rebuilds, just as they are for retrofits. In Ohio, the Diesel Emission Reduction Grant program is a prominent source of this funding.

Repower older diesel engines.

Diesel engines can be repowered and in the process be made to produce significantly lower emissions, especially diesel particulates. Diesel engine makers can perform these repowers. Some diesel engines also can be repowered to operate on compressed natural gas ⁴. These CNG repowers also significantly curb emissions, especially particulates and nitrogen oxides.

Replace older diesels with newer engines.

Finally, the sixth strategic component to consider is engine or vehicle replacement. This refers to the replacement of an older diesel engine and/or vehicle with a new engine – either diesel or one with the same or very similar performance specifications and application that operates on another fuel. This fuel may include an alternative fuel such as compressed natural gas (CNG) or propane.

Engine replacement typically, though not always, qualifies for diesel cleanup grant programs ⁵. The key caveat is that most grants ⁶ usually will not pay for simply replacing an old diesel vehicle at the end of its useful life or at a standard replacement schedule ⁷. That older diesel engine must have some years, typically five, of useful life. A further caveat is that an old engine with useful life must be permanently disabled, destroyed or completely re-manufactured so that it attains current engine year emissions standards.

Of course, engine replacement is an expensive option. However, it can achieve large emissions reductions on a per-unit basis. Also, if the diesel engine is replaced with one that has comparable performance specifications but can use an alternative fuel, it may offer significant life cycle cost benefits due to reduced fuel costs. The actual life cycle comparison will depend on the vehicle, its application, amount of fuel consumed per year and over the vehicle’s lifetime, availability of tax credits and other factors. In some instances vehicle replacement may offer the best business case for a fleet. Key to viability of vehicles that can use alternative fuels like CNG or propane will be development or accessibility of refueling facilities. Ohio Green Fleet sponsors such as Clean Energy, Firm Green Energy (for CNG), and Ohio Power and Light (for propane) may be able to develop refueling facilities. Under any circumstances, this option certainly requires fleets to plan and perhaps even coordinate plans together ⁸.

Notes

¹Numerous peer-reviewed studies rely upon USEPA and other public heath data sources. Please see the references listed at www.ohiogreenfleets.org.

² Ibid.

³Union of Concerned Scientists, Clean Fuels Ohio, Ohio Environmental Council, and a few others have used this “Six R’s” terminology. Ohio Green Fleets has reordered the list of the R’s to provide fleets with a strategic process we believe will facilitate development of the most effective overall strategy.

⁴Emissions Solutions Inc has developed a system that repowers certain International diesel engines such as the DT 466 as CNG engines.

⁵ In Ohio, replacement qualifies under the DERG program but not the Ohio EPA School Bus Retrofit grant program.

⁶Both the Ohio DERG and USEPA Midwest Clean Diesel grants will only fund replacements if old engines have useful life.

⁷An exception is the USDOE Clean Cities grant program. A possible exception is the Congestion Mitigation and Air Quality program – specifically grants that may be awarded through a regional Metropolitan Planning Organization.

⁸For example, fleets in close proximity interested in pursuing CNG or propane replacements may want to coordinate development and use of refueling facilities, possibly in partnership with a private station developer.