Abstract
Freight rail is more energy-efficient than truck transport over long-haul distances, offering a low-energy and emissions-intensive option for transporting freight. This study evaluates techno-economic analysis and life cycle assessment of seven alternative unblended fuels for freight locomotive engines─biodiesel, renewable diesel (RD), bio-oils, methanol, dimethyl ether (DME), ethanol, and ammonia─across 16 fuel pathways utilizing soybean, corn, woody biomass, renewable hydrogen, and waste sources, e.g., sludge, manure, and industrial CO2, and compares these to conventional diesel. The minimum fuel selling price (MFSP) ranged from $2.05 to $8.27 per diesel gallon equivalent (2020 US dollars), with biocrude and RDs produced from hydrothermal liquefaction (HTL) of sludge having the lowest MFSPs due to coproduct credits and avoided waste treatment cost. Life cycle GHG emissions ranged from −41 to 53 g of CO2e/MJ. RD from waste via HTL achieves negative emissions by diverting sludge/manure from GHG-intensive conventional management. Few pathways such as biocrude, methanol, and DME require additional control for SOX emissions in the refinery, while ethanol, FT-diesel, and bio-oil require additional control for particulate matter emissions. Bio-oil and RD from sludge have lower marginal abatement cost or MAC (–$38/tonne CO2 lowest) while methanol and ammonia with renewable hydrogen have higher MAC ($490/tonne CO2 maximum).
| Original language | English |
|---|---|
| Pages (from-to) | 15741-15750 |
| Number of pages | 10 |
| Journal | Environmental Science and Technology |
| Volume | 59 |
| Issue number | 30 |
| DOIs | |
| State | Published - Aug 5 2025 |
Funding
This study was sponsored by the U.S. Department of Energy (DOE), Bioenergy Technologies Office (BETO) under the DE-NL0040198 multilab project and was performed by Argonne National Laboratory operated by UChicago Argonne, LLC under Contract No. DE-AC02–06CH11357, Pacific Northwest National Laboratory operated by Battelle Memorial Institute under Contract No. DE-AC05–76RL01830, and Oak Ridge National Laboratory operated by UT-Batelle LLC under Contract No. DE-AC05–00OR22725. The authors would like to thank Ben Simon, technology manager at the Bioenergy Technology Office of U.S. Department of Energy for his strategic direction and support for this work. We would also like to thank Drs. Natalie Popovich, Nazib Siddique, Ingrid Busch, and Doris Oke for their review and feedback on the manuscript. The views expressed in this article do not necessarily represent the views of the U.S. Department of Energy or the United States Government. The U.S. Government retains, and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed, or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
Keywords
- Tier 4 locomotive emission standard
- biofuel
- carbon credit
- catalytic fast pyrolysis
- e-fuel
- hydrothermal liquefaction
- indirect liquefaction
- pump to wheel