Can a tough and weedy shrub solve all of our energy problems and stop runaway climate change?
Don’t be ridiculous—of course it can't. But that, briefly, was the hype surrounding Jatropha curcas, a poisonous plant that grows wild in tropical climates. Jatropha seeds are saturated with oil that can be easily processed into biofuel, and the hardy plant can grow on what's politely called "marginal land": wasteland that's sandy, rocky, dry, or nutrient-poor.
By embracing jatropha, optimistic environmentalists said, nations could avoid displacing agricultural crops and causing food shortages, and could also prevent forests being cleared for biofuel plantations. Over the past five years, tropical nations rushed to start jatropha programs, while Goldman Sachs reportedly cited the plant as one of the best candidates for biodiesel production. Several airlines have even begun test flights with a jatropha-derived jet fuel.
Then, facts began to emerge to combat the hype. A study published in the Proceedings of the National Academy of Sciences in June confirmed that jatropha can grow on marginal land, and can survive droughts—but it won't do much more than survive, and it certainly won't produce bumper crops of oily seeds. To get the best yields, jatropha needs fertile soil and significant amounts of water, like most other crops. Just last week, the oil company BP withdrew from a partnership with the jatropha biofuel company D1 Oils, which aimed to plant 1 million hectares of jatropha.
But that's not the end of the story for the would-be wonder crop. While "jatropha euphoria" may be fading along with the hope of an easy answer, some are turning their efforts to a hard, slow process that is as old as civilization: the painstaking process of domestication.
"Jatropha really is an undomesticated plant," says Robert Schmidt, chief scientist with the startup company SG Biofuels, which focuses exclusively on jatropha. "All our typical crops have decades, centuries, millennia of domestication to make them most useful to us." The company aims to compress that domestication process into just a few years, to create a new form of jatropha that has fewer needs and produces more oil. As they're starting with a plant whose seed typically contains 30 to 40 percent oil, the company's scientists believe their tinkering has a good chance of paying off.
The company's methods include old-fashioned fieldwork, time-honed crossbreeding techniques, and a dash of genetic engineering. SG Biofuels scientists have been collecting jatropha plants from around the world to assemble a broad variety of strains; the company's "genetic resource center" now contains about 5,500 seeds. Schmidt and his colleagues are now working to identify strains with useful traits, like ten cold-tolerant strains that were found growing high in the mountains of Central America. Using such strains, "we could expand the growing range into southern California," says SG Biofuels president Kirk Haney.
After scientists have identified strains with useful traits—like cold-tolerance, drought-resistance, and above all, high oil yields—those plants can be propagated and crossbred to create the über-jatropha plant.
The results of such a breeding program can be dramatic, says Schmidt. For an example he looks back to the early 1900s, when the British decided to grow wild South American rubber trees on plantations in Indonesia. The plantation owners noticed that 10 percent of the rubber trees were producing about 25 percent of the yield. "It was obvious to them that they should take just those trees and propagate them," says Schmidt. It takes about five years for a rubber tree to grow from a seed to productive maturity, so progress was slow. But after 20 years, rubber yields had increased by 400 percent.