Hydrothermal conversion of big bluestem for bio-oil production: The effect of ecotype and planting location

► Bio-oil yield was significantly affected by ecotype and planting location. ► Planting location was more influential than ecotype in bio-oil yield. ► Bio-oil C and O contents were significantly affected mainly by ecotype (p < 0.01). ► Planting location alone had no significant effect on bio-oil C or O contents. ► Big bluestem and switchgrass have similar potential for bio-oil production via HTC.