Wayne Keith has converted his pickup to run on scraps of wood from his Alabama (US) sawmill. The heart of the wood-powered vehicle is a gasifier, which basically converts solid fuels into gaseous ones. Though the fuel in their tanks is liquid, gasoline and diesel engines actually run on vapour. Thus, the wood gas produced in a gasifier (also known as producer gas or syngas) will burn in a gasoline or diesel engine with only minor modifications to the motor itself.

When heated in the absence of oxygen, wood gives off a mixture of gases made up of about 20% hydrogen, 20% carbon monoxide, and small amounts of methane, with nitrogen accounting for the rest. The gasifier keeps the gas from combining with oxygen until it reaches the engine, where it combusts, giving off carbon dioxide and water vapour as waste products.

This technology is not new. Wood gas has been produced for heating since at least the late 1700s, and has been used to run engines since the 1880s. During WWIIs petroleum shortages, wood gasification for transportation fuel became rapidly and briefly widespread, both in the Europe and the US.

Keiths converted pickup starts on gasoline. As a supercharger pulls air through the gasifier, he tosses a piece of burning newspaper into the bottom of the unit. The burning paper ignites the charcoal, and 45 seconds later, the engine is running on wood gas alone (though it takes longer to get to full power).

With two separate accelerators, Keith says, the pickup can switch from gasoline to wood fuel in the blink of an eye. The gasifier looks like a large drum standing upright in the bed of the pickup. Keith has added five layers of insulating material around the outside of the unit, so that even with temperatures reaching 2,500F inside, he can stack bales of hay next to it without risking a fire.

Thus equipped, the pickup easily reaches cruising speeds of 100 km/h. A similarly modified truck pulls a trailer loaded with 17 round hay bales, weighing 500 kg apiece.