A review covering biodiesel life cycle assessment, energy in/output at FAME production, and CO2 balance sheet concerning rapeseed vegetation (C passing into atm., soil, roots, seeds and oil, and consumed by microorganisms). Emission of CO2 in prepg. a blodiesel is estd. at 3.22 kg/kg biodiesel (+ ca. 0.7 kg/kg in the agricultural area).