Biofuels were once regarded as impractical for aviation because most freeze at the low temperatures encountered at cruising altitudes. But tests show jatropha, whose seeds yield an oil already used to produce fuels like biodiesel, has an even lower freezing point than jet fuel.
Biofuels emit as much carbon as kerosene-based jet fuel, but jatropha — a Mexican plant that grows in warm climates — absorbs about half the carbon that jatropha-based fuels release. Air New Zealand’s proposed blend, for example, would mean a one-quarter reduction in the carbon footprint of standard jet fuel.
Many biofuels — like ethanol, which is produced from corn — have been blamed for raising the price of food by diverting it from kitchen tables to engines. While the link between biofuels and grain prices is debatable, Mills said that jatropha plants would not compete with food or other commercial crops since it can grow on land that would make poor farmland and needs little water.
