Jatropha – a possible source of bio diesel?

Air New Zealand has been trialling for Boeing and Rolls Royce a mix of traditional kerosene fuel with oil from the Jatropha plant seed (Jatropha Curas) in one of its airplanes. Jatropha oil mixed with kerosene improved fuel consumption by slightly more than one percent, which could lead to savings of four and a half tonnes of carbon dioxide over a typical long haul flight if the plane was powered by a fifty/fifty mix of Jatropha oil and kerosene.

The news has been such that the money people are getting excited; Goldman Sachs are sensing an opportunity and Governments are beginning to incentivise the growing of Jatropha plants in the hope that this will be a good cash producer for farmers.

No doubt the markets are getting very excited by the fact that Jatropha can be grown in non arable areas, is very resistant to drought, and therefore growing the plant in these places will not deprive the ever growing world population of a source of food by making over agricultural land to fuel production, neither should it affect tropical forest, those lungs and carbon stores of our planet, in the way that growing for palm oil has.

The Jatropha plants (there are a number of them) are native to Central America, but have been grown in tropical and sub tropical regions throughout the world. The seeds of the plant contain oil – on average around 27% – which can be processed into fuel.

The Air New Zealand experiment laid down three conditions:-

  1. The Jatropha must be harvested from places where Jatropha has not been planted at the expense of existing food supplies; this condition – one of “sustainability” is hard to define and harder to police.
  2. The fuel must be as good as what is being used now
  3. The Jatropha fuel should be cost competitive; heavan forbid that any commercial organisation should wish to pay over the going rate for fuel in order to cause less damage than they cause at present.

Jatropha is already used in India to help fuel trains; it is grown extensively in Brazil and in the Philippines with many emerging nations looking to switch to Jatropha growing as a cash crop. At the moment Jatropha sells at the equivalent of $44 per barrel – cheaper than crude oil.

But before we all rush to hail Jatropha as the next big thing in the energy world we ought to remember that the balance of nature, when changed, can gave unintended consequences and often these cure can be worse than the disease. We have already found out (or at least some of us have) that biomass is really a “dirty” form of renewable energy, and probably not that renewable in the long run; will we discover that like biomass, Jatropha is merely renewable, and not clean renewable.

In the Philippines, one of the world’s leading Jatropha producers, three professors of crop Science, at the University of the Philippines in Los Baños, Ted Mendoza, Oscar Zamora and Joven Lales, have been studying Jatropha. [1]

They find that for Jatropha to become viable, from the point of view of the farmers, the retail price of diesel must be above a set amount and that the drop must have a high fruit yield of 36 tonnes per hectare which yields on average 36% oil, and that the by products of the crop produce an additional 50% income.

These viability figures are for the Philippines; most nations have their own system of farming subsidies and fuel taxes that will distort these viability figures. However, the findings of the professors become more interesting when they explain the physical features of Jatropha which impact upon its usefulness as an energy source.

  1. No variety of Jatropha in the Philippines produces 36% oil; the highest extraction is 34%, under laboratory conditions, with average extraction rate at 30%. It takes five years to get a decent crop of Jatropha buts from planting. That is a “dead” period, so far as farmers are concerned. It also impacts upon the time that it will take to breed strain with higher fruit and oil yields – seven cycles of plant selection will take 35 years, unless you opt for genetic modification.
  2. Jatropha has a toxin called curcin which is poisonous to animals and possibly to other plants.
  3. According to the professors from Los Baños, large corporation with idle land, not suitable for farming, may plant Jatropha as a cheap way of getting something from that land. The do caution against small farmers adopting the crop; its long growing period and the uncertainty of the market demand for the crop are all factors, together with the poor yields.  
  4. Planting Jatropha in marginal soils – one of the criteria of the Air New Zealand project, will not yield anything worthwhile. If the soils are poor and the weather dry the yields will be very low and very slow. In times of drought Jatropha adapts by shedding leaves and not growing seeds until the rains start again.
  5. Planting Jatropha in good farmland will produce better yields but where Jatropha grows, mangoes, cashew, siniguelas, duhat, jackfruit, bignay, cassava, sweet potato and many legumes and tropical fruits will also grow.
  6. Two products can be made from Jatropha – biodiesel and soap.
  7. The professors seem to indicate that there is encouragement to grow Jatropha in the Philippines which is based upon some fair dodgy financial projections.

For the time being at least it seem that Jatropha will not be the way of reducing emissions from the aviation industry. Air New Zealand’s initiative is interesting but they could save far more carbon dioxide by reducing their flights by 10% – a simple measure which only has a positive environmental impact but possibly a negative financial impact. It is often like that; the simplest things will save carbon but they will also provide us with a simpler life; is that such a bad outcome?


[1] Published in the Philippine Journal of Crop Science Vol. 32 No. 1 on Jan. 17, 2009

2 Responses

  1. Hi

    Great to hear about how jatropha helps poor farmers! I wondered if you could comment on this article about Jatropha Plantations for Bio Fuel?


    Here is my basic method for refining Crude Jatropha Oil (CJO) Any Comments on this method greatly appreciated!


    Warm Regards


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