Commercial vehicles are beginning to adopt alternative energy sources, but the transition remains slow. Batteries and an array of renewable fuels are seeing more usage, but costs and infrastructure remain hindrances for these fragmented technologies.

Alternative fuel consumption was about 3% of the market in 2015, according to NTEA - The Association for the Work Truck Industry. Speakers at NTEA’s Green Truck Summit in Indianapolis in March highlighted a number of advances that are occurring as global regulations tighten emissions levels.

Carlton Rose, President of Global Fleet Maintenance & Engineering at UPS, highlighted the company’s expanding fleet of alternative vehicles, noting that vehicles using these fuels traveled over 1 billion miles since 2000.

In Eugene, OR, the Water & Electric Board is using renewable diesel to slash carbon output by 38%. Gary Lentsch, fleet supervisor, said renewable diesel can be used without changing engines or storage systems, bringing significant reductions in carbon. Maintenance costs have declined, which helps offset the 3.5 cent per gallon premium over conventional diesel, he said.

Panelists largely touted financial benefits over emissions reductions. That’s necessary for the long-term success of new energy vehicles. Many speakers highlighted applications where reduced operating and maintenance costs combine to trim costs over diesel alternatives. In city buses, lifetime fuel cost reductions are augmented by low maintenance costs for comparatively simple battery-powered vehicles.

“Up front, a transit bus will cost about $300,000 more,” said Jack Kitowski, Division Chief, Mobile Source Control Division, California Air Resources Board. “Even with that, lower operating costs make up for that over its lifetime. The components are so much simpler that much less maintenance is required, around $100,000 less over the life of a bus. Batteries usually last 14 years, the typical life of a bus.”

Craig Moore, COO at liquefied natural gas provider Kinetrex Energy, said renewable natural gas can eliminate SCR (selective catalytic reduction) systems and provide 90% less NOx and 92% fewer greenhouse gases. Liquid natural gas sells for less than diesel, and there’s an 11 cent benefit if trucks burn renewable natural gas. The payback for converting to LNG comes in three years or less.

However, there are still obstacles. Keynoter Wilfried Achenbach, Senior Vice President of Engineering and Technology at Daimler Trucks North America, highlighted the challenge that batteries must overcome. The energy density of lithium ion is 0.08 kW·h/kg, compared to 10 kW·h/kg, so diesel can store “a lot of energy in little space.”

Reuben Sarkar, the U.S. Department of Energy’s Deputy Assistant Secretary for Transportation, added that current projections for battery prices target $125 per kW·h by 2022. But $80 is the crossover point to equal the costs of gas-powered vehicles. If today’s low fuel prices hold, it will take another decade to hit an equivalent price point, he said.

A lack of refill stations is another hurdle. There’s a multitude of alternative fuels, making it difficult to build a solid infrastructure. Until that changes, applications will proceed primarily in environments like buses, refuse trucks and other fields where vehicles can recharge or refill at central depots.

Today’s low oil costs are making it difficult for developers of both vehicles and fuel supplies to deploy profitable strategies. Many concepts for producing gases have been proven by prototypes, but suppliers can’t yet justify construction of large facilities.

“Trash to gas is a great way to get to zero emissions,” said Mike Britt, UPS Ground Fleet’s Director of International Operations, Maintenance & Engineering. “Using cow manure from a dairy farm is effective. There aren’t any technical bridges to cross, just strategic and financial bridges.”

While fleets currently use a combination of batteries, liquefied gases and renewable diesel, researchers are still striving to create commercially viable hydrogen-based systems. Many speakers touted its potential for impacting both costs and emissions, even though practical deployments are still some time off.

“We are definitely drinking the hydrogen cocktail,” Britt said. “We’ve modeled our fuel cell technology based on our Napa Valley route (where heavily loaded vehicles traverse hilly terrains). If they can operate there, they can operate anywhere.”