Jatropha nursery, Tamil Nadu, India. Courtsey D1 Oils

First published in Infocus: Jatropha, a supplement to Cleantech magazine, May 2008,  Copyright Cleantech Investor 2008

Jatropha Curcas L, originated from Central America and now grows widely around the world, typically in warm tropics. It needs a hot environment and a lot of sun. To thrive, it needs at least 600 mm of rain annually, but it can reportedly survive three years of drought by dropping its leaves. Although it can grow on marginal land, the growing conditions have a significant impact upon the yield. Jatropha grows best on sandy/loamy soils.  

The Jatropha plant typically grows between three and five metres in height but it has been reported to have reached heights of as much as ten meters. It can produce several crops during the year, depending upon soil moisture and temperatures, but typically develops fruit during winter. The fruits form in bunches of around ten and are initially olive green. As the seeds mature, the fruit changes colour to black. It can be harvested by hand or using olive harvesting equipment.

Jatropha has traditionally been used in regions such as West Africa, where it was planted in order to prevent soil erosion, and for soil improvement. In India and in some parts of Africa, Jatropha is used as a hedge to protect other crops from livestock (animals avoid the Jatropha leaf).

The Jatropha fruit has a husk (seed coat) which can be removed after sun drying to reveal the Jatropha seeds. The husk can be composed. The seeds need to be dried before pressing by a mechanical seed press – either powered by hand or with an electric or diesel motor. The seed has oil content of between 32% and 45%.

Jatropha performs well when grown with other crops. The Jatropha plant can be intercropped with cash crops such as coffee, sugar, fruits and vegetables. Intercropping also offers scope for the growing of subsistence crops such as corn (maize) on land which would otherwise not be suitable for food crops.

Jatropha has been used over the years in soaps and for medicinal purposes. The shoots and leaves contain the chemical curcin, which has antiseptic qualities, but can be poisonous in large quantities.

Jatropha begins yielding oil in the second year after it is planted, although it takes five years for the plant to reach maturity. It has a lifespan of between 40 and 50 years.

Crude Jatropha oil, produced by cold pressing, can be combusted as a fuel without being refined. The crude oil is typically used to fuel a direct injection diesel motor to run the pressing machinery.

The UNDP has over the years promoted small scale rural applications for crude Jatropha oil, such as electrification and water pumping, over the years. Local scale Jatropha projects can be found in countries such as Mali, in West Africa, where Dutch NGO, the FACT Foundation, has installed jatropha-fuelled electricity generators.

Jatropha by products include press cake, which can be used as a fertilizer.

Jatropha was first tested as a possible feedstock for transport fuel in francophone West Africa in the 1970s, in response to the oil crisis. The testing programmes were largely abandoned when oil prices fell back.

Biodiesel derived from Jatropha nut kernels has properties similar to those of biofuels obtained from oilseed rapes. With oil prices soaring and concerns about ‘peak oil’, the potential for Jatropha as a feedstock for bio fuel has become recognised around the world in recent years.