By Peter Sopher, Senior Associate at Clean Energy Ventures
Special to The Digest
Automobile manufacturers such as Nissan, Chevy, Tesla, BYD, and others have successfully elevated battery-powered electric cars, vans, and even buses from being niche, expensive, and poor-performing transportation solutions to becoming mainstream and affordable with marked improvements in performance and range. But a BloombergNEF forecast shows that the 2040 market penetration of these EVs remains a relatively small proportion of the overall fleet, especially for heavy commercial vehicles. To meet our greenhouse gas mitigation goals and impending state and national emissions regulations, we need new solutions to road and other highly polluting segments of the transportation sector – air, ocean, and rail transport, for example – where economic and performance traction of clean fuels are critically lagging.
One sub-segment of the transportation sector that is especially difficult to decarbonize are those that rely on heavy-duty diesel engines. According to the 2014 ICCT State of Clean Transport Policy report, heavy-duty on-road vehicles emit 3 GtCO2e per year globally, accounting for 34 percent of transportation sector emissions and 8 percent of the 38 GtCO2e of global anthropogenic emissions. Diesel-fired long-haul trucks, which are used for cross-country and long-distance ground shipping, make up an overwhelming portion of these emissions.
The challenge is the ideal engine for a long-haul truck is one that minimizes weight, as well as refueling time and cost for cross-country trips, while maximizing torque and other performance measures. Better engine performance means more reliable deliveries across diverse climates and terrains, which ensures that customers are receiving their products on time. Due to strict 80,000 lbs. weight limits on long-haul trucks, minimized engine weight enables maximized cargo capacity, meaning more revenue potential. Meanwhile, fewer and faster refuels lowers the average time per trip, equating to higher hourly revenues per truck.
At present, the popular alternative to diesel is electric trucks, which are at least a decade away from competing on economics and practicality. For long-haul trucking, the switch to an electric battery with a similar capacity adds approximately 10,000 pounds of weight compared to diesel engines, meaning that 10,000 fewer pounds of cargo can be carried per trip. For cross-country trips, electric-powered trucks require 5-10 recharges compared to 1-3 refuels for diesel-fueled trucks, and recharging takes substantially longer than filling up a liquid fuel tank. Furthermore, electric trucks used for long-haul applications suffer from significantly higher cost and weather-related challenges, such as a lower battery capacity in cold weather, relative to diesel.
For economic long-haul trucking, liquid fuels are still the best option at this point, but traditional diesel carries a high climate cost in terms of emissions, not to mention NOx and particulates. The clean fuels that best fit long-haul trucking applications are alcohol-based ones including bioethanol and methanol, both of which pose less of an environmental impact compared to petroleum-based diesel. Major engine manufacturers are beginning to invest in new technologies to decouple diesel fuel from the diesel engine, such as diesel-style engines that can be powered by alcohol-based fuels, which require no sacrifice in performance or cost and comfortably meets the strictest NOx, particulates and CO2 emissions standards. Technologies like these are expected to be commercially available within five years, bringing the same benefits of diesel-fueled trucks in terms of optimized weight and the frequency, duration, and cost of refueling.
Another consideration for the future of long-haul trucking is the infrastructure, where the framework for climate-friendly alcohol-based fuels is far more developed than that of other clean alternatives like electrification or hydrogen. Depending on how it’s evaluated, U.S. ethanol production is 25 to 50 percent that of diesel; 17 billion gallons/year of ethanol is produced (an energy equivalent of 11 billion gallons/year of diesel) compared to 40+ billion gallons/year for diesel, so the global commodity precursors for alcohol-based fuels are readily available. Furthermore, many fleet operators own the refueling infrastructure used by long-haul trucks, and climate-friendly alcohol-based fuels like ethanol are easily transportable and can be stored in conventional storage tanks currently used for gasoline.
By contrast, the infrastructure challenges for e-trucks and hydrogen are daunting. It is difficult to predict the time horizon for the implementation and adoption of cross-country electric charging infrastructure. Supercharging long-haul e-trucks at scale requires substantial charging stations, adding strain to renewable power load curves (or requiring storage back-up), and, in many locations, could require additional power generation sources and agreements with local- and state-level regulators.
Similarly, hydrogen brings major challenges as well. Transporting gaseous fuels is no small task, a key reason why the adoption of natural gas-fueled buses and trucks has been so disappointing even with extremely low natural gas prices on a dollars per gallon equivalent basis. The build-out of infrastructure for hydrogen transport is in a nascent phase and will require continued, substantial momentum from corporations and local and national governments around the world to develop in a robust manner over the coming decades, with competition from stationary hydrogen storage and use of green hydrogen in industrial and chemical applications.
And speed matters for the climate fight – we can’t wait decades for electrification and hydrogen-based technologies to be fully viable alternatives; we have to start implementing innovative technologies that can make a difference sooner. Climate-friendly alcohol-based fuels have as clean (or cleaner) emissions profiles for the medium-term horizon than electricity and hydrogen. According to Argonne National Labs’ Greenhouse Gas, Regulated Emissions, and Energy Use in Transportation Model (GREET), there are significant life-cycle CO2 reductions by transitioning from petroleum diesel to corn-based ethanol (39%), sugarcane-based ethanol (71%), corn stover ethanol (89%), flare gas methanol (86%), and biomass (94%). As sustainable harvesting and renewable power increasingly penetrate society, these emissions reduction percentages will see dramatic increases to 90%+ in the future.
It is also a naïve oversimplification to insinuate that electricity, alcohol-based fuels, and hydrogen are completely clean today, as coal-fired power plants still fuel electricity generation, fossil natural gas is burned to produce most hydrogen, and alcohol-based fuels are often produced with fossil-fueled machinery. In fact, according to EIA, carbon free sources (renewables and nuclear) are projected to power only 50% of the grid by 2050. But these fuel sources are still considered climate-friendly alternatives because they have a fit in a low/zero-carbon world once power grids and other inputs are eradicated of fossil fuels.
Beyond emissions, alcohol-based fuels also have an impact on land-use. The opportunity cost of using lands to grow fuels is real and needs case-by-case consideration. But we’re optimistic in how technology has been evolving to sustainably grow food and fuels more efficiently. Alcohol fuels are ready to help address the climate challenge today, and we believe that alcohol fuel producers will continue to respond for demands to increase the sustainability of their product in the future.
Tough-to-decarbonize subsectors, such as long-haul trucking, are where innovations are most impactful for an energy transition. Climate-friendly alcohol-based fuels will bring about superior net carbon benefits relative to grid electricity in most locations through at least the 2030s, and once the grid is 100 percent zero carbon, alcohol-based fuels like renewable methanol will also be carbon-free. By recognizing the potential impact of using climate-friendly alcohol-based fuels to transform emissions from long-haul trucking, investors such as Clean Energy Ventures will continue to fund enabling innovations as a step towards combatting our climate crisis.
This article was developed as an excerpt from the white paper, Long-haul trucking, and the critical role for climate-friendly alcohol-based fuels in an energy transition, by Clean Energy Ventures, June 2020.