This study evaluates the net energy efficiency and economic feasibility of switchgrass (Panicum virgatum L.) as a cellulosic bioenergy crop. Field trials were conducted on 10 farms across the midcontinental U.S., covering 3 to 9 hectares, to determine net energy and economic costs based on known farm inputs and harvested yields. The results show that switchgrass produced 540% more renewable energy than non-renewable energy consumed, with an average net energy yield (NEY) of 60 GJ·ha⁻¹·y⁻¹. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY compared to human-made prairies with low agricultural inputs. The estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than those from gasoline. The study highlights the potential of switchgrass as a sustainable and economically viable bioenergy crop, with further improvements expected through genetic and agronomic advancements.This study evaluates the net energy efficiency and economic feasibility of switchgrass (Panicum virgatum L.) as a cellulosic bioenergy crop. Field trials were conducted on 10 farms across the midcontinental U.S., covering 3 to 9 hectares, to determine net energy and economic costs based on known farm inputs and harvested yields. The results show that switchgrass produced 540% more renewable energy than non-renewable energy consumed, with an average net energy yield (NEY) of 60 GJ·ha⁻¹·y⁻¹. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY compared to human-made prairies with low agricultural inputs. The estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than those from gasoline. The study highlights the potential of switchgrass as a sustainable and economically viable bioenergy crop, with further improvements expected through genetic and agronomic advancements.