The New York Times featured an article on Sunday about a promising new biodiesel source called Jatropha curcas or Barbados Nut – a weed that is currently used to shield food crops from animals in Northern Africa, Southeast Asia and the Caribbean. The plant seems ideal for both farmers and the environment: it is accustomed to dry conditions and is poisonous to pests, thus eliminating the need for complicated irrigation or dangerous, expensive pesticide use. The prospect of Jatropha oil as a source of biodiesel is so lucrative, in fact that British Petrolium, Daimler-Chrystler and other large fuel and automotive corporations are pouring millions into research and cultivation.
This is good news for farmers. Jatropha can grow in the rocky or nutrient poor soil that rejects all other crops and yields more biofuel per acre than other sources like corn and soy. This is partially because the seed of the Jatropha, from which the oil is extracted, is about 40% oil. To the world’s poor, Jatropha could be a fortune growing out of their rocky terrain.
Of course, like most plant oils, the glycerin content in the Jatropha oil is high, making the natural raw product too viscous for car engines. Cultivators must process it by extracting the glycerin and replacing it with methanol, which is alcohol cultivated from wood. While the two-step process of extracting and replacing does not use a great deal of energy, a great deal is expended on the transformation of wood to alcohol. Without knowing the amount of methanol used per liter of Jatropha fuel, it is impossible to calculate this drawback.
That said, the low sulfur and high oxygen content give the Jatropha oil a combustion rate that only releases the amount of CO2 that the plant drew in from the atmosphere as it grew. This is effectively recycled CO2, a far greater prospect than its fresh equivalent.
Surely Jatropha is more efficient than its purely ethanol or ethanol-gas mix counterparts. The energy-heavy process of cultivating corn for ethanol actually spends more energy than is gained from the resulting oil. Sugar cane, while an easier, more efficient crop to grow, is cultivated in climates where jungle is often cut down to make way for cane fields. Since a jungle stores over twice as much carbon as a sugar cane field of the same size does, the process of converting land for crops is incredibly carbon-costly.
While research is ongoing, jatropha looks like a more sustainable and socially equitable option for the biodiesel industry.
