The journey to zero emissions has begun, but a global fuel system producer believes that several energy sources — including renewable natural gas (RNG) — will be needed to reach the goal.
“There is not one solution that can replace diesel,” Hexagon Composites CEO Jon Erik Engeset said in a March 23 press conference. “We firmly believe there’s got to be a mix, depending on the geography, depending on availability, depending on the application of the trucks.”
The need for such options becomes increasingly important against a backdrop of ever-tighter emissions standards and the limited ranges of emerging battery-electric options. Ninety-seven percent of heavy trucks continue to be powered by diesel, and in Europe the share even increased by half a percentage point from 2021 to 2022.
“It is possible to decarbonize the land transportation sector by 2050 if you apply the right mix of technologies and energy alternatives,” Engeset said.
Benefits from wells to wheels
RNG, for example, can reduce carbon dioxide emissions by 80-200% on a well-to-wheel basis, considering how the fuel is produced, and be delivered using traditional natural gas pipelines. Today, 64% of the natural gas used for U.S. transportation is renewable. In California, the share is 98%.
“California fleets that fueled with bio CNG [compressed natural gas] in 2021, they achieved carbon negativity for the second full year in a row with an annual average [carbon intensity] score of -44.41 – that’s lower than any other fuel and the only carbon-negative outcome mix in the entire [Low Carbon Fuel Standard] program,” said Dan Gage, president of NGV America.
Then there are the tax incentives for RNG. The U.S. Inflation Reduction Act extended an alternative fuel tax credit of 50 cents per US gallon to January 2024, said Ashley Remillard, senior vice-president – legal and government affairs. The technology-neutral Clean Fuels Production Credit of $1 per gallon comes in 2025-27, and a new Investment Tax Credit supports digesters to make the fuel. (All figures in US dollars.)
Diesel faces a tougher battle. The U.S. Environmental Protection Agency’s Clean Trucks Plan is slashing NOx limits to 0.035 grams per horsepower-hour in 2027, which will drive up the cost of diesel equipment, Remillard added.
“The EPA restriction on NOx is going to force fleets either to continue to use very expensive diesel or pivot to CNG,” said Eric Bippus, Hexagon Agility’s senior vice president – global sales and marketing. “They’re running out of daylight.”
Evolving natural gas engines
The challenges are not limited to North America.
Updated European targets look to slash medium- and heavy-duty vehicle emissions by 45% in 2030, 65% in 2035, and 90% by 2040, said Harmen Dekker, CEO of the European Biogass Association and secretary general of NGV America.
It’s an aggressive timeline that has some manufacturers questioning their future plans for developing diesel engines. And jurisdictions including Germany are already pushing back on emissions targets for lighter vehicles.
“Decarbonization of the heavy-duty transport sector must begin now. We recognize that there is no one size-fits-all clean-energy solution,” Remillard said. “But the path to decarbonization can be accelerated immediately by targeting the high-emitting longhaul heavy-duty transport segment — and RNG solutions leverage technology, infrastructure and an energy source that is readily available today.”
The introduction of big-bore natural gas engines, namely Cummins’ plans for a 15-liter offering, represents one of those technologies.
Today there are more than 100 mature natural gas vehicle offerings produced by 15 OEMs in the European Union and North America, said Eric Bippus, Hexagon Agility’s senior vice president – global sales and marketing. And the 15-liter engine will see natural gas emerge as an option for the heaviest on-road vehicles.
UPS natural gas experience
The fuel has already proven itself in lighter applications. UPS, for example, has been running 12-liter natural gas engines since 2012, after a pilot project showed they could run more than 950 km without refueling. In 2013, natural gas was also US$2 per gallon cheaper than diesel, and the trucks were using 20,000 gallons of fuel per year. Even the natural gas fueling infrastructure was designed to last 20 years.
“The business case was solid,” said Mike Casteel, a retired UPS fleet procurement director.
Last year, the fleet had more than 60 natural gas fueling stations, 4,000 heavy-duty natural gas trucks, and 6,000 medium-duty natural gas trucks. The fuel also continues to offer a $2 per gallon benefit over diesel in some jurisdictions.
“Fossil natural gas is not going to move the carbon reduction meter by itself,” Casteel said. “Renewable natural gas, however, is.
“For heavy-duty fleets, from well to wheel, RNG is the only alternative to diesel that has the potential for significantly reducing carbon emissions while also meeting financial targets and operational demands… It’s low-risk. No other technology is even close.”