NACFE's "Run on Less" Highlights Diverse Fuel Efficiency Metrics in Freight Transportation

The North American Council for Freight Efficiency's (NACFE) "Run on Less" initiative has once again commenced, featuring an impressive array of freight vehicles powered by various fuels, including battery electric, renewable diesel, natural gas, and hydrogen fuel cells. This diverse lineup reflects the choices fleets are making in their pursuit of enhanced freight efficiency and reduced emissions. However, it raises an important question: if the goal is to demonstrate real-world efficiency, why are many trucks still falling short in terms of cost and greenhouse gas emissions?

This year's theme, dubbed the "messy middle," seeks to highlight the potential options that fleets consider plausible. It aims to present them on a level playing field, allowing stakeholders to make informed decisions.

Yet, there is a risk that the complexity of data—speed traces, charge curves—might obscure the critical outcomes that matter most: cost per mile and well-to-wheel emissions per mile. By placing these two metrics front and center, the remaining data can serve as context rather than a distraction.

Cost per mile is defined as the energy cost required to transport a loaded truck over a specified route, while well-to-wheel emissions per mile quantify the greenhouse gases produced throughout the energy production and usage cycle, normalized to a distance of 1,000 miles. These figures must be grounded in the specific duty cycle and geographical context, as carbon intensity varies significantly from one region to another. For example, hydrogen sourced from natural gas has a different environmental impact compared to hydrogen produced with renewable energy sources.

To derive these numbers accurately, the analysis employs realistic data from operational fleets, accounting for charging losses, local grid carbon intensity, and upstream methane leakage rates. The results are revealing: the five battery electric trucks operating in California and Arizona exhibit varying greenhouse gas emissions based on the regional grid's efficiency, averaging around 492 kg of CO2e per 1,000 miles. Concurrently, the energy costs for these trucks align closely with their emissions, reflecting the existing commercial tariffs.

Renewable diesel appears competitive initially, with a life cycle carbon intensity suggesting it could be a viable option. However, its benefits depend significantly on the feedstock used; while waste-based sources may yield lower emissions, crop-based sources increase them substantially. Natural gas, on the other hand, faces inherent challenges due to methane slip and leakage, resulting in a substantial carbon footprint that cannot be overlooked, despite seemingly attractive pump prices.

Meanwhile, hydrogen fuel cells struggle to align with the mission of the Run on Less initiative under current U.S. conditions, primarily due to reliance on steam methane reforming. The high retail prices and emissions associated with hydrogen production from natural gas present significant barriers to its adoption in freight transport. Comparatively, diesel remains a benchmark, with renewable diesel marginally cleaner but more costly.

The initiative would benefit from clearer visual representations of the data, such as bar charts illustrating well-to-wheel emissions and energy costs per 1,000 miles. These visuals would enable fleet managers to quickly ascertain how various fuel options stack up against one another. It is critical that the data presented includes vital disclosures regarding hydrogen sources, renewable diesel feedstocks, and natural gas assumptions to foster transparency and replicability.

As fleets approach procurement decisions, battery electric vehicles are emerging as a practical choice across various duty cycles, demanding thoughtful planning for depot power and charging infrastructure. Renewable biofuels can serve as a transition for legacy assets, provided they utilize waste-based feedstocks. However, natural gas presents a climate risk that fleets cannot mitigate, while hydrogen requires a low-carbon supply and reliable infrastructure to be viable.

The landscape of freight efficiency is evolving, and the NACFE's initiative is positioned to shed light on the most effective pathways forward. By prioritizing cost per mile and well-to-wheel emissions in their evaluations, "Run on Less" aligns with its mission to guide fleets, shippers, and regulators toward more sustainable choices. The findings indicate that while renewable diesel has a role to play in the short term, battery electric technology is leading the way in both cost-effectiveness and emissions reduction in the regions where these trucks operate.