1929 Ford Model A Tudor with wood gas system attached. Photos by author.
The efforts to find a sustainable replacement for gasoline precede the term “e-mobility” that currently dominates press releases in the auto industry. During the Second World War, a widespread fuel shortage led many motorists to experiment with cars and trucks that ran on wood, coal, or both.
Wood-powered vehicles have been around since the auto industry’s earliest days, but they didn’t rise to prominence until the end of the First World War. Alarmed by gas shortages during the war, many countries in Europe encouraged private companies to find a new type of fuel. Electric cars were considered, but they were ultimately deemed too impractical for an array of reasons, including the limited driving range they offered and the extra weight added by the batteries. Wood gas generators emerged as the ideal compromise.
In 1922, the Automobile Club de France organized an endurance rally open to wood gas-powered trucks. The participants needed to cover about 75 miles in two days. The technology advanced at such a rapid pace that the following year’s edition took participants on a 745-mile, 12-day trip. In 1925, the rally was 1,300 miles long and it lasted three weeks.
At its peak, the wood gas industry attracted big names like Renault, Latil, Panhard, and Berliet. However, it soon became evident that the system’s cons outweighed its pros. Gasified trucks burned a phenomenal amount of wood, and the whole setup was incredibly heavy so it reduced the all-important payload. At the time, the transport industry was shifting towards trucks that could drive further with heavier loads, so demand for a system that reduced both range and payload was low at best. Besides, what were the odds of another gas shortage sending shockwaves across the continent? Berliet’s research and development program was one of the last still around when it shut down in 1927.
The gasifier strikes back
Wood-powered cars triumphantly returned to the automotive landscape during the Second World War. While major automakers had long given up on the technology, smaller companies had continued to invest in it and developed more compact kits that could be mounted on regular passenger cars. The issued encountered during the 1910s and 1920s hadn’t been fully solved yet, so running a wood-powered car or truck was often a last resort. Still, 12 percent of the 71,690 passenger cars registered in France in January of 1944 were equipped with a wood gas generator, and 58 percent of the 120,567 trucks accounted for used the system, according to Transports en France pendant la Guerre.
A hands-on manual published in the late 1930s named Manuel Pratique des Automobiles a Gazogène explores the requirements of operating a wood-powered vehicle. It explains the average truck typically burned 220 pounds of wood every 62 miles, and it strongly advises against running out; filling up isn’t as simple as running into the forest with an axe to chop down a tree.
In many systems, the wood needed to be cut into chunks no bigger than three inches long and two inches in diameter. It needed to be dry, meaning it had to be cut at least six months prior to being burned and stored out of the rain. Finally, hardwoods like birch and oak were preferable, while resinous woods such as cypress were to be avoided.
Some of the smaller stoves fitted to cars burned charcoal. The advantages were that charcoal was lighter than wood, and it was easier to store because it took up less space. However, it was much more sensitive to humidity than wood. Other wood gas systems burned a mixture of charcoal and wood, while a few were powered by anthracite. Burning any of the aforementioned materials produced a flammable syngas that replaced gasoline once it had been properly filtered and cooled.
Regardless of power source, wood gas systems were primarily made up of a stove, a cooler, a filter, and a network of pipes. The stove was a large, often cylindrical component typically attached to the back of the car, though it was sometimes mounted on a separate trailer. The location of the filter and the radiator varied from system to system.
Simply bolting a wood gas generator onto the back of a car reduced the engine’s output by up to 40 percent. Motorists could slash that figure by lowing the compression ratio, and they could also offset the power loss by fitting a shorter rear gear. The manual points out that wood gas-powered cars were best-suited to country driving even when they were adequately modified because their acceleration remained lackadaisical at best, and they were jerky to drive in stop-and-go traffic.
Today, wood gas generators are little more than a footnote in the history of the automobile. The kits that powered cars on both sides of the pond during the war were scrapped as soon as gasoline became readily available again. Finding a car still equipped with a period wood gas generator is easier said than done, but we tracked one down in a museum-in-the-making named Provence Collection located near Draguignan in the picturesque south of France.
The car in question is a 1929 Ford Model A. Jack Wilcock, one of the museum’s expert mechanics, explained the car comes from Denmark, and it’s fitted with a wood gas system manufactured by Skandinavisk Motor Co. His research revealed the kit was an expensive, high-end model. It replaces the fuel system altogether, which wasn’t always the case; some cars could run either on wood gas or standard gasoline.
The wood goes into the stove that’s mounted on the back of the car. The gas-charged smoke produced by the chunks as they burn rises, goes down through a layer of charcoal, and up again into a tube that runs under the car. It enters a two-in-one filter/radiator unit mounted in front of the stock, Ford-badged radiator before being routed to the cylinders through the A’s stock intake manifold.
Wood is loaded through the lid on top of the stove, while charcoal is loaded through two fist-sized holes cut into the bottom part of the unit. Ash is removed through a bigger hole at the very bottom of the stove. At startup, a pipe concealed under the passenger-side running board is used to test whether the gas is pure enough to burn in the four-cylinder. This operation is dangerous because the car can belch out a massive flame.
The A is not currently running, but it was driveable about three years ago. When he started it, Wilcock remembers that it smoked so much the neighbors called the fire department because they thought the workshop was burning down. It emits less smoke as it warms up, he points out as his dad – the garage’s second mechanic – proudly shows a video of the Ford moving under its own power. It looks fascinating, to say the least. Luckily, we’ve been invited back to drive the Model A as soon as it’s up and running again.