AbstractVegetable oil from canola and camelina can be converted to renewable diesel via hydroprocessing. In this study, a techno‐economic model was developed to estimate the cost of vegetable oil production and the production plant economic optimum size using canola or camelina as feedstock. Minimum, average, and maximum yield cases were considered. If canola and camelina meal can be sold for $0.26/kg, in the average yield case the optimum plant size and minimum cost of oil production is 140 million L/year and $0.63/L for a canola‐press plant, 190 million L/year and $0.55/L for a canola‐solvent plant, 90 million L/year and $0.28/L for a camelina‐press plant, and 120 million L/year and $0.28/L for a camelina‐solvent plant. If camelina meal cannot be sold, the cost of oil from camelina‐press and solvent plants at their optimum sizes is $1.04/L and $0.82/L, respectively. Field cost is the largest cost component and it makes up 75–85% of the total oil production cost. A sensitivity analysis found that field cost and meal price have the greatest effect on oil cost; the optimum size of the plant, on the other hand, is most sensitive to transportation, capital, and operating and maintenance costs. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd