The Jatropha family of shrubs gets a bad rap in some parts of the world where it is known as ‘black vomit nut’. In Australia where it’s a declared weed it’s called ‘bellyache bush’, and makes humans and livestock ill if eaten.
But it also makes an aviation grade alternative fuel to kerosene, and with simpler refining is an alternative to diesel oil.
Sebastian Remy, the head of alternative fuel research for Airbus is in the country talking up Jatropha only days before Air New Zealand test flies a 50% blend of this artificial kerosene in a Boeing 747.
Remy says the weed, pardon, miracle plant, could cut the release of fossilized carbon in Australian fueled aircraft by about 50% by 2020 if such a blend is made from home grown Jatropha nuts, from plantations in the otherwise largely useless land that surrounds arid parts of the continent receiving less than 300 mms of rain a year. Think of the zone between cattle country and desert, or better still, think of cattle proof fences.
This is the land area involved assuming for the larger green circle with a diameter of 650 kilometres a yield of one tonne of nuts per hectare per annum, or at a yield of 10 tonnes in the comparatively smaller green circle of 100 kilometres.
However there are hurdles to clear. Remy says the right type of Jatropha has to be selected and then proven to be compatible with other land uses and the native flora and fauna. He has been well briefed on the cane toad catastrophe and similar great triumphs of environmental intervention in Australia.
“There are many ways in which different types of the plant can lead to an alternative to kerosene which is indistinguishable from the current jet grades in every vital characteristic,” he says.
“One of those pathways could be right for Australia. If it was more viable to source a replacement fuel for surface vehicles from Jatropha you would need around ten times the area to meet current national consumption, or at the higher yield of 10 tonnes per hectare, the equivalent of a circle with a diameter of around 300 kilometres.”
Airbus is not quite as bullish as Boeing about the pace at which algae produced octanes could replace fossilized carbon releasing kerosene in its entirety. His counterpart at Boeing, Billy Glover, says all the world’s aviation fuel could be produced in algae farms covering a much more compact area the size of Belgium. While Remy doesn’t disagree with the prediction he says Airbus thinks the timing for that belongs to a more distant future.
“One important feature of Jatropha is that is a biological fuel that doesn’t interfere with agricultural production as does methanol, which isn’t a useful alternative to kerosene because it contains less energy for the same volume and freezes solid even at low altitudes.”
Consider methanol for jets scratched from further consideration.