Push to zero emissions might be opening a door for propane engines

Propane truck

500,000 United States Postal Service (USPS) employees are entrusted with
delivering mail to every residential and business address in the U.S. each day.
Much of that mail, though, first moves on contractor vehicles that transport it
from distribution center to distribution center, and then to local post offices.

Some contractors are quite savvy,
such as Butch McAbee and his wife, Lisa. The McAbees, who own McAbee Trucking
in South Carolina, have held a USPS contract for 49 years and currently operate
a fleet of 21 tractor-trailers and 15 straight trucks. For a mail operation, it
is remarkably robust.

Lisa McAbee told FreightWaves the
company likes to buy new equipment when possible, and a few years ago made the decision
to move into alternative fuels. After a 2017 foray into compressed natural gas,
the fleet is now adding propane vehicles.

“The United States Postal Service
has its own sustainability plan,” McAbee said. “Since we’ve been in business
with them for 49 years, we want to help them achieve that plan … by
implementing propane rather than diesel into our contracts.”

McAbee Trucking will take delivery
of a Ford F-650 with 26-foot van body with liftgate in April, and the plan is
to acquire six additional vehicles — all Ford F-750 models with 26-foot van
bodies. McAbee said the coronavirus has disrupted those plans, but they still
expect to put them into operation this year. She said the vehicles are modified
slightly to lessen the overall weight, allowing non-CDL drivers to drive them.

“It will still pull the same load
and it will still get the same fuel mileage, and maybe even a little better
fuel mileage because the truck is lighter,” she said.

Ford’s F-650 and F-750 models are
also available with gas engines, but McAbee said that wasn’t a consideration
for their trucks, which typically drive between 60,000 and 70,000 miles a year.

“We did not consider gas because
propane emissions are less than gasoline and the cost for propane is still less
than gas,” she said. “At one time [gas] would have been an option but now with
the emissions it’s a no-brainer.”

The McAbees are exactly the type of
customer who Tucker Perkins, president and CEO of the Propane Education &
Research Council (PERC), thinks are perfect for propane. The trucks drive
dedicated routes, can return to base for refueling, and are in line with
industry pushes to reduce emissions. As Tucker sees it, that societal push
toward zero emissions is opening the door for propane. A breakthrough in engine
technology is only accelerating that push.

“For five years we’ve been working
with Cummins on the next generation of propane engines,” Perkins said during
the Green Truck Summit in Indianapolis earlier this month. “That’s the engine
we’ve been waiting for to breach the Class 8 market.”

That engine, the Cummins 6.7L
propane engine, leverages components from Cummins’ 6.7L diesel engine but is a
direct propane injection powerplant that produces 880 lbs.-ft. of torque and
375 horsepower, Perkins said. Brake thermal efficiency (BTE) matches that of
diesel and produces 11% less CO2 emissions than a diesel engine with a similar

Importantly, the engine produces
between 17% and 25% less CO2 emissions than currently produced propane engines
as a result of its BTE. Current propane engines include a Cummins 5.9L engine,
a Ford 7.3L and a GM 6.6L.

The first part of the equation —
the push to zero-emissions engines — is an inherent part of the propane story,
Perkins noted. Propane engines, he said, can already meet the proposed NOx
emissions standards. Current Environmental Protection Agency (EPA) standards
call for engines to achieve 0.2 grams NOx per brake horsepower-hour (g/bhp-hr).
In January, EPA issued an Advanced Notice of Proposed Rulemaking that would push that limit down to 0.02 g/bhp-hr. The rulemaking
is in response to a push from California and 19 other states to lower the

Perkins said propane engines
already operate at 0.01 g/bhp-hr. Coming advances in direct injection, higher
compression ratios, cooler exhaust gas recirculation, start/stop cylinder
deactivation and hybrid solutions will help propane engines stay at these low

The development of renewable
propane that benefits from inexpensive and abundant feedstock ensures zero
particulate matter release for the engines, another advantage over diesel,
Perkins said.

The counterargument is that propane
doesn’t have the same power as diesel, and with a lower British thermal unit
(Btu) rating per gallon, fuel economy does suffer a little. However, the fuel
is significantly cheaper than diesel and “its lower per-gallon cost can quickly
offset the lower fuel economy,” the U.S. Department of Energy’s Alternative
Fuels Data Center explained.

Steve Whaley, director of Autogas
business development for PERC, told FreightWaves the average per-gallon price
of propane, as of the beginning of March, was $1.27 on the West Coast and $1.45
on the East Coast. A 37-cents-per-gallon tax credit is also available
currently, Whaley told FreightWaves at the Work Truck Show in Indianapolis.

“When you add up how much it costs
to drive 100 miles, we’re 50% cheaper than diesel,” he said.

The other issue is infrastructure.
Propane is not available at your regular fuel stop, and at this point, is best
suited for operations where the vehicle returns to base or has propane fueling
infrastructure along the way – exactly how McAbee Trucking plans to use its new
propane trucks.

“It’s serving the same purpose as
compressed natural gas but at a cheaper price,” Lisa McAbee said.