Fuel production improves food production:: An integrated system using the physic nut (Jatropha curcas L.)

The use of vegetable oil as an engine fuel has a long and eventful history, during which technical problems have largely been solved. The economic conditions, however, do not yet allow for a breakthrough of vegetable oil fuel use in most of the industrialised and developing countries. A specific approach to overcome the economic bottlenecks is described in this paper giving the example of a German Development Project in Mall. Its primary aim is not the use of vegetable oil from the physic nut as fuel, but rather the use of the oil as a crucial element to activate a closed system, combining ecological, economic and income generating effects, the latter specifically for women. These effects only materialise through an a rational use of the non edible oil of the Jatropha plant. Jatropha not only bears oil-rich seeds, it can also be planted in the form of hedges to protect gardens and fields from grazing animals whilst warding off soil erosion. Thus, it is possible to speak of a positive feedback between energy production and agricultural production: The more energy is produced by the hedgerows of Jatropha plants, the more food production is strengthened. The recycling of the oil cake as organic fertiliser is of particular importance in this context. The technologies introduced into this Jatropha System are the well known hand- or mechanically driven oil presses and pre-chamber Diesel engines. While the latter are already available on the local market in various makes, the presses can be produced at the local level at affordable prices. The project's activities focus on training and dissemination of the relevant know-how. This is done by using local, often non;governmental institutions and by offering advice to farmers and rural communities interested in making use of the Jatropha System. The economic analysis shows very positive impacts, if direct and external effects are considered. Even in a completely non-subsidised situation, in which all investments are financed by agricultural bank credits, a considerable internal rate of return on the order of 26% is achieved. The break-even-analysis shows that the system becomes economically viable when the oil press is used at 25% of its capacity.