Renewable natural gas can be used in near-zero-emission natural gas engines. - Photo: Clean Energy

Renewable natural gas can be used in near-zero-emission natural gas engines.

Photo: Clean Energy


Not a week goes by, it seems, without another announcement related to zero-emissions commercial vehicles, whether battery-electric or fuel-cell electric technology. It’s an exciting time, to be sure. But for heavy-duty trucks, advocates of clean diesel engines and renewable fuels believe there’s still a place for these technologies, which are getting “greener” all the time and more cost-effective than electric vehicles, at least at this point in their development.

Clean Diesel Proves Itself at the Ports

The Diesel Technology Forum points to the Clean Trucks Program at the Port of Long Beach as an example. In 2019, trucks serving the POLB accounted for just 7 tons of fine particle (PM 2.5) emissions, down from 186 tons in 2005.

“This 97% reduction in emissions is largely due to the introduction of new technology diesel trucks even as cargo volumes in the port have expanded by 14%,” said a DTF press release. “In 2005, trucks were the second leading source of all PM 2.5 emissions after ocean going vessels. In 2019, port trucks were the second smallest source of PM 2.5 emissions after cargo-handling equipment.”

The Clean Trucks Program at the Ports of Long Beach and Los Angeles requires that all trucks meet the latest tailpipe emissions standard for PM 2.5, and new trucks entering service in the port as of 2018 must meet near-zero tailpipe emissions standard for ozone-forming compounds (NOx) as well. According to the latest data, 90% of the estimated 14,000 port trucks entering and exiting marine terminals in southern California are powered by diesel. About 65% are of the latest-generation diesel technology that achieve near-zero emissions performance for both NOx and PM 2.5. The remaining 10% are primarily natural gas-powered vehicles, many now running on near-zero engines with renewable natural gas.

Renewable Diesel Offers Drop-In Sustainability

Use renewable diesel fuel in that cleaner-burning modern diesel engine, and you have an even “greener” truck.

Renewable diesel is made from sustainable sources such as natural animal fats, vegetable oils, greases, plant waste, and other sources. Neste, which makes renewable diesel, says it can be used without modification in all diesel engines, can be stored and distributed via existing infrastructure, and can reduce greenhouse gas emissions by up to 80% compared to fossil petroleum diesel.

“California’s climate change and clean air ambitions are great, but the cost and pace for how truck manufacturers and fleet operators will be able to comply with these rules is uncertain,” points out Carrie Song, Vice President Sales, Renewable Fuel at Neste.

As a result, she says, older-model diesel trucks could be in service for another generation as fleets take time to actually adopt more expensive zero-emission vehicles. “There also remains the reality that diesel powered trucks will still enter California from neighboring states. According to Bloomberg New Energy Finance data, a mere 19% of heavy-duty vehicles will be electric in 2040. So, low-emission solutions will need to be developed and deployed to fill this gap during the transition.”

Neste also points out that it and other producers can verify their entire renewable supply chain protects human rights, does not harm the environment, complies with ethical business practices, and does not compete with the food system.


Combine clean-burning diesel engines with renewable diesel fuel for a double dose of green. - Photo: Neste

Combine clean-burning diesel engines with renewable diesel fuel for a double dose of green.

Photo: Neste


Renewable Natural Gas

Another renewable fuel is renewable natural gas. As Equipment Editor Jim Park reported in the October issue of HDT, lifecycle analysis by the California Air Resources Board shows that organic waste-derived biomethane is the lowest-carbon commercially available transportation fuel option that exists. In fact, when made from food waste or animal manure, the fuel is “net-carbon-negative.”

Park points out that perhaps the best imaginable use for RNG is in the waste-hauling sector, where fleets hauling trash to landfill can literally dump a load of garbage at one side of the facility and drive around the other side and fuel up with the biomethane produced onsite.

NGVAmerica, which advocates for natural gas, just released a study using New Jersey that analyzed the costs and impact of transitioning that state’s entire 10,000 refuse truck fleet from diesel to both renewable natural gas and battery electric.

Refuse trucks are well-suited to both natural gas and electric operations. But compressed natural gas refuse trucks can be fueled by the very waste they collect, as biomethane created by landfills is recaptured and turned into fuel.

The study found that the RNG refuse trucks outperformed their electric counterparts in total “well-to-wheel” NOx emission reductions, and reduced more harmful CO2-equivalent greenhouse gas (GHG) emissions in total than the battery electric alternative. In addition, RNG-fueled trucks are already readily available at a cost only slightly more than diesel-powered versions, notes the group, while electrified versions are expected to be much more expensive, at least in the near term.

Most fleets aren’t going to be replacing their entire fleet with battery-electric or fuel-cell trucks anytime soon. But there are many paths on the quest to be more environmentally friendly, green, and sustainable. You don’t have to wait for zero-emissions trucks to make progress.





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