DEF Supplies

One year after the Environmental Protection Agency (EPA) 2010 heavy duty truck emission standards mandating near-zero levels of NOx (nitrogen oxide) and PM (particulate matter) went into effect, auto parts retail shelves, private fleet terminals and truck stop fueling plazas are stocked with expanding inventories of diesel exhaust fluid (DEF). Industry analysis finds that there will be more than enough DEF to operate 2010 and 2011 selective catalytic reduction (SCR)-equipped trucks.

Industry reports show nearly 300 DEF bulk storage installations in place at truck stops and fleet terminals. More than 150 new bulk tank installations (tank storage volumes between 1,000 to 4,000 gallons) were projected to have come online across North America by mid-2011.

To meet DEF demand that is projected to reach 350 million gallons by 2015, high-volume truck stops are quickly moving from 1,000- to 2,000-gallon bulk tanks to larger 10,000-gallon underground tanks.

Pilot and Flying J truck stops will increase the number of fuel lanes dispensing DEF from 68 to 1,000 by this October. TravelCenters of America and Petro Stopping Centers are rolling out new “1+1” single-dispensers that simultaneously fuel trucks with diesel and DEF, authorizing both transactions and payment, and eliminating the need for drivers to move trucks for both fills.



Starting this year, the new generation of clean diesel technology for off-road engines and equipment, known as Tier 4, will make its way onto the construction and industrial jobsites and farmlands around the country.

Tier 4 compliance dates are based on the size of engine (hp and /kW-hr) and other factors. Tier 4 regulations allow for an interim step to give equipment manufacturers flexibility in delivering substantial PM reduction followed by substantial NOx reduction.

Beginning in 2014, final Tier 4 standards will require near-zero emissions or 99 percent NOx reduction and 96 percent PM reduction. In concert with Tier 4 off-road mainstream applications will be introduction of clean diesel technologies and emissions standards for marine and railroad applications.

While the EPA mandate for Tier 4 off-road emissions compliance applies only to new engines and equipment, states focused on immediate air quality improvements, like California, are developing programs to accelerate adoption of low emitting new equipment and retrofits - most of which will demand ready supplies DEF.



Tier 4 impacts the work horses of mobile power units. Different than on-highway, this machinery is jobsite bound and used primarily in land grading, construction, road building, demolition, mining, farming and other industrial applications. Productivity is not measured in miles per gallon but in reliability and hours per gallon.

Fueling and fluid refilling are primarily handled onsite by mobile refuelers and fluid distributors, called “wet hosers,” or at home terminals. The supply chain for DEF is significantly different than on-highway applications.

However, like on-highway, fuel cost and supply are key factors and rising fuel costs require cost containment.

For the first time, most off-road equipment will incorporate emissions control technologies - either exhaust gas recirculation (EGR) or SCR. Applications that are best suited for SCR include airport ground support equipment, quarry trucks, mobile and aerial cranes and military vehicles where lightly loaded engines idle for long periods or have intermittent duty cycles and construction (up to 750 horsepower).

These applications require reliable power over short periods of time but do not generate enough heat to passively regenerate or clean diesel particulate filters (DPF), leaving them more susceptible to clogging up.

Also ideal for SCR technology are high-powered tractors for agriculture, forage harvesters and combines above 100 horsepower. Some equipment manufacturers report fuel consumption with SCR-equipped engines are running 19 percent below equipment industry averages without SCR.



Packaging and placement of the aftertreatment system and size requirements for air intake systems to meet the need for increased airflow and cooling most likely required redesign of engine compartments to manage the new emissions technologies. Some equipment manufacturers will place the systems inside a reworked sheet metal skin while others will place systems in traditional locations with additional shielding and mounting hardware.

With so many different applications, Tier 4 engines and equipment have a variety of differences depending on manufacturer. These include horsepower ratings, smaller engine displacement, differing power and torque performance, higher fuel economy and other factors.

Depending on its size, Tier 4 machinery equipped with SCR will require an extra storage tank to hold up to 15 gallons of liquid DEF. DEF consumption will be dependent on equipment utilization, load factors and idle time and, like on-highway, indicator lights will warn the operator when DEF supply is running low.

Different than previous equipment in many cases, Tier 4 engines will be electronically controlled by computers that will monitor and adjust the fuel and air mixture for optimized emissions and engine performance.



Growing pressure on government and private industry to “go green” will mean that equipment owners will increasingly encounter contract specifications, job bids, project riders and contingencies that consider the emissions profile of their equipment in the award evaluation. Public projects such as transportation, facilities and infrastructure will expect use of either new or retrofitted low emissions equipment.

According to a report from the Diesel Technology Forum, “outside of California there are presently no state laws requiring the mandatory retrofitting of existing, privately owned diesel engines or equipment. However, there are a growing number of states, including Illinois, New Jersey, New York and Rhode Island, that require the retrofitting of state-owned equipment or that which is under contract to the state.”

Since some of the oldest engines and machines have 20 to 40 times the emissions levels of a new Tier 4 engine, it is projected that state and regional officials will be looking for cost-effective ways to accelerate the upgrade to new and retrofitted lower emissions technology.



Going forward beyond 2014, the industry’s focus will be on increasing fuel economy and its corresponding reduction of carbon dioxide (CO2). This focus may lead to further exploration of hybridization and more integrated use of hydrogen injection technologies, electronic motors, batteries and storage systems.

Long-term, the goal to increase fuel economy, reduce CO2 and decrease use of fossil fuels supports continued adoption and adaptation of SCR technology, increasing exponential demand for DEF supplies to serve both on-highway and off-road systems.