Unlocking the biofuel power of cover crop in Washington State: Enhancing potential through hydrothermal liquefaction

Journal Article · Mon Aug 25 00:00:00 EDT 2025 · Biomass and Bioenergy

DOI:https://doi.org/10.1016/j.biombioe.2025.108311· OSTI ID:2586905

Santosa, Daniel Miki ^[1]; Potter, Teal ^[2]; Pierobon, Francesca ^[3]; Göreke, Dilara ^[4]; Meyer, Pimphan Aye ^[5]; Kruger, Chad E. ^[2]; Norberg, Steven ^[2]; Collins, Douglas ^[2]; Male, Jonathan ^[2]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Washington State University, Pullman, WA (United States)
2. Washington State University, Pullman, WA (United States)
3. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Washington State University, Pullman, WA (United States); University of Washington, Seattle, WA (United States)
4. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
5. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

This study evaluates cover crops in Washington State (WA) as a renewable feedstock for hydrothermal liquefaction (HTL), supported by techno-economic (TEA) and life cycle (LCA) analysis. In the Pacific Northwest, fallow land is the common winter practice, generating no income for farmers. Over three years, field trials at two representative sites—Puyallup (cool, wet) and Othello (irrigated, no-till)tested triticale, hairy vetch, crimson clover, winter pea, and fava bean preceding cash crops. Biomass yields, composition, soil impacts, and net revenue were assessed across removal treatments. HTL conversion produced 32–37 wt% biocrude, lower than 48 wt% for sewage sludge, with modeled cradle-to-grave carbon intensities of 26–31 g CO₂e/MJ and minimum fuel selling prices (MFSP) of $6.75–$$\$$7.18$ per gallon gasoline equivalent (GGE), comparable to other lignocellulosic feedstocks. No significant changes were observed in soil carbon, nitrogen, or subsequent cash crop yields after cover crop removal. Farmer profitability was possible, particularly for triticale and hairy vetch at $$\$$60$ per dry ton. To address seasonal variability, blending with wastewater sludge was evaluated. All scenarios delivered >70 % carbon intensity reductions relative to fossil fuels, and with Renewable Identification Number (RIN) credits, MFSPs below $$\$$2.5$/GGE were achievable. These results demonstrate that cover crops can generate new revenue streams for farmers while serving as a flexible, low-carbon feedstock. Integrating cover crops with waste biomass offers a practical pathway to expand the bioeconomy and support year-round renewable fuel production.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725; AC05-76RL01830
• OSTI ID: 2586905
• Journal Information: Biomass and Bioenergy, Journal Name: Biomass and Bioenergy Vol. 203; ISSN 0961-9534
• Publisher: Elsevier BV
• Country of Publication: United States
• Language: English

Related Subjects

And life-cycle analysis
Biofuels
Cover crop
Hydrothermal liquefaction
Techno-economic analysis