Lorries that run on liquefied natural gas are already common on German motorways. EnviTec makes the renewable version: biogas from farm residues, cleaned into biomethane and chilled to around minus 160 °C until it becomes a liquid that fills the same tanks.
Most sustainable aviation fuel today is made from used cooking oil and animal fats, and there is not enough of either to fly the world. LanzaJet starts from ethanol instead, a liquid that can be made from crops, farm waste, municipal rubbish or even captured industrial gases.
Old frying oil and slaughterhouse fat are not obvious truck fuels. Neste hydrotreats them into a diesel that is chemically almost the same as the fossil kind, so a bus, lorry or generator can switch over at the pump with no changes.
Every October and November, farmers in Punjab and Haryana set fire to the stubble left after the rice harvest, and smoke drifts over Delhi. Praj Industries' enfinity process is meant to turn that straw into fuel ethanol instead.
When pine and spruce are cooked into pulp, a dark, sticky oil separates out. For decades it was burned for heat or sold to chemical makers. At Lappeenranta in south-east Finland, UPM turns it into a diesel and a naphtha that drop straight into today's tanks and crackers.
