A specific fuel for agricultural machinery: study of four agricultural biofuel production chains

Abstract

Fuel has become indespensable to agriculture: it represents 30% of the hourly cost of a tractor and raises the problem of the "energy fragility" of modern agriculture, entirely dependent on oil supplies and too sensitive to fuel market prices. With the planned reduction of oil resources, this paper gives technical, economical and environmental issues related to the choice of a specific agricultural fuel for tractors. Four options are presented dealing with two liquid fuels - pure vegetable oil and ethanol - and two gaseous fuels: syngas and biogas. All have been tested, sometimes for several years in the 80s. For each of them, the production process is described. The energy potential and environmental assessment is then evaluated. Three of them are immediately applicable to agricultural machinery and have significant potential for fossil fuel substitution.