I thought that I'd take a look at Jatropha to see what all the interest from companies like D1 and BP is about. One thing that I've been wondering about is how much like a cropping plant, such as apples, wheat, rice or soya is it. One of the characteristics of these plants is that they all more or less produce ripe fruit at the same time as a singular annual event. This has advantages, none of the crops that I've mentioned would ever have made them the stars of dining tables across the world.
doesn't do that, according to one US source
Reproduction.—Flowering in India occurs from February through July (Parrotta 2001). Sometimes both flowers and fruits will be present at the same time on plants. Upon drying, the capsule valves spring open propelling the seeds a few centimeters. It is not known if there are other seed dispersal mechanisms. Seeds collected in Puerto Rico averaged 0.017 + 0.001 g/seed or 59,000 seeds/kg. The seeds of this collection were highly variable in weight (C.V.= 53.7 percent) and just 4 percent germinated. Collecting seed in quantity is difficult because capsules are mature for only a short period before discharging their seeds, and there are only a few capsules per large plant at any time
Now that may not be the most likely variety of Jatropha for biofuels but it points to a plant that will need a lot of harvesting. This doesn't matter if labour is cheap and working in the fields is what people do, but I think there could be two longer issues
There will be a need to develop varieties that crop at different times of the year or that produce whole trees or groves of jatropha ripening at the same rate. It's less likely to be a problem now, but finding people to do the work could be difficult if the wealth spreads to the pickers. Rising wealth means higher living standards and that means more demand for manufactured goods. Malayisia's rubber plantations are a good example of an industry that struggles to find people in the competition with well paying jobs in air conditioned factories.
All surmountable I'm sure. Perhaps some one from BP or D1 oils could let us know how they're going to get around these problems. It would be interesting.