The previous post provided an introduction to Jatropha curcas, a tropical, oil-producing shrub. In this essay I want to get into why I believe there is great potential for jatropha to make an impact on the world’s energy supply. I will also explain the hurdles that need to be overcome.
Jatropha has many qualities that make it an attractive biofuel option. One, it is tolerant of dry conditions and marginal soils. This is a big plus, because it opens up areas for cultivation that would otherwise be unsuitable. The type of land with great potential is land that is being degraded, or turned into desert. Desertification is a significant problem worldwide, and occurs when dry land is overexploited. Think of the Dust Bowl in the 1930’s and you start to get a picture of how desertification impacts and threatens lives.
There are techniques for combating desertification. Plants that can grow on dry, marginal land have the potential to start providing a matrix for the soil to prevent the soil from being eroded by the wind. There are a number of candidate plants that can be used to combat desertification. However, there has to be adequate incentive to grow plants for combating desertification. I suppose the ideal plant would be one that can supply food while at the same time rehabilitating marginal soil. I am unaware of candidate plants in that category, but I presume some exist. A close second, however, would be a plant that can provide a quality fuel – and thus a cash crop – on marginal soil. Jatropha curcas is such a plant.
Comparison with Palm Oil
Where can jatropha be used in such a role? Have a look at the graphic below:
It is true that the African Oil Palm, from which palm oil is derived, is a much more prolific producer of oil than is jatropha. In fact, palm oil yields – as high as 5 metric tons per hectare – places the African Oil Palm as the world’s most productive lipid crop. But there are significant disadvantages/risks that go along with palm oil. First is the fact that the range of the African Oil Palm is a narrow band close to the equator (see the graphic above). While this is fine for countries like Malaysia, Indonesia, and Thailand – where it has provided a valuable cash crop for farmers – it means that India and most of Africa is unsuitable for cultivation.
Of a more serious nature is that expansion of oil palm plantations – driven by biofuel mandates in Western countries – has led to a dramatic expansion in many tropical countries around the equator. In certain locations, expansion of oil palm cultivation has resulted in serious environmental damage as rain forest has been cleared to make room for new oil palm plantations. Deforestation in some countries has been severe, which negatively impacts sustainability criteria, because these tropical forests absorb carbon dioxide and help mitigate greenhouse gas emissions. Destruction of peat land in Indonesia for oil palm plantations has reportedly caused the country to become the world’s third highest emitter of greenhouse gases.
Because the range of jatropha is much greater, there is substantial potential to alleviate poverty throughout Africa, India, and many poor countries by providing a valuable cash crop for farmers. Further, it is unlikely to contribute to deforestation as more productive oil producers provide greater incentive to go that route. (Note: While the range is clearer greater than for palm oil, native jatropha is not frost resistant, which means the range shown in the figure above is overstated. The graphic indicates that jatropha could be grown in the Dallas area, and we certainly get hard freezes and frost here.)
The essay up until now may make jatropha sound like a real silver bullet for addressing fossil fuel dependence. Alas, there are no silver bullets. And in fact, the hype for jatropha has gotten out of hand. As I noted in the essay describing my trip to India, I found the present situation with jatropha to have been overhyped.
Jatropha has negatives just like every other energy source. First, it is toxic to humans and livestock. As pointed out in the previous essay, the Western Australian government banned jatropha as an undesirable, invasive species in 2006. Second, because it has not been domesticated, yields are highly variable and the fruits ripen over a broad time range. Third, it is labor intensive to gather the fruits and extract the oil. Finally, while it can be grown on marginal land, there has to be a logistical infrastructure in place to economically get it to the market. Much of the world’s marginal land lacks such an infrastucture. For instance, when I was in India last year, I saw great swaths of borderline desert land that might be used to grow jatropha. The problem is that it was all remote, with no infrastructure.
The answer to many of these concerns potentially lies in the fact that jatropha is still a wild plant. Selective breeding and/or genetic engineering likely have great potential to address many of these issues. Because the world is just now beginning to seriously experiment with jatropha, there is naturally a learning curve to climb. It may turn out that some of the issues are indeed insoluble, but I wouldn’t bet on it. What is needed is a serious, dedicated investigation into the genetics of jatropha, in conjunction with a major plant-breeding effort. We need some modern-day Luther Burbanks working on this problem. By doing so, jatropha may one day live up to the hype.
There are numerous jatropha resources out there. Here is a sampling.
The site is quite a rich source of jatropha information, and if you are interested I would encourage you to explore it. It is devoted to the concept of providing renewable energy while creating new opportunities for farmers in poor nations