There are three generations of biofuels. The first generation, he explains, were “largely made from food stock” – crops grown especially for fuel. But that wasn’t sustainable and it brought up ethical issues.
Second-generation biofuels “either use food waste, the husks of corn for example, or biomass, for example forestry waste, or indeed household waste.
“Finally, there are third-generation biofuels, sometimes called the e-fuels or synthetic fuel, and without going into too much chemistry, these are the more advanced fuels.
"They’re often called drop-in fuels because you can effectively just put them into any engine, without modification, whereas engines that run on extreme ethanol mixes, such as used in Brazil [for road cars], require alteration.”