Wood Fired: Producer Gas Vehicles During World War II
I wouldn’t say I’m a huge fan of steampunk, but I love learning about ideas that could’ve been. The monowheel is a perennial favorite of mine (and one that would do well to return today), as well as Henry Ford’s early experiments with ethyl alcohol-powered cars - which had been a feature on many Model T’s until the technology was killed by the Prohibition. It’s a shame that some ideas, especially that one, were abandoned irreversibly (in the mainstream, at any rate) by chance.
One such topic I’ve recently become aware of, however, is the wood gas car. Like the ethyl alcohol car, which ran on that fuel because it could be made easily on a farm, it was born out of necessity. During World War II, wood gas (also known as producer gas) vehicles became a popular and essential substitute for gasoline and diesel, which were rationed for military use. And it wasn’t just one side, either; the technology was popular throughout Europe, everywhere from Scandinavian countries (with over 110,000 between the three of them) to central Europe (France was especially notable, having 65,000 during the period). Germany actually had around half a million wood gas vehicles during the war.
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The principles behind wood gas are relatively straightforward. Chopped pieces of wood (often wood chips) are burned in a gasifier, a large tank with an outlet at the top. The resulting gas then travels through that opening, is cooled in a radiator, filtered, and sent into the vehicle’s original carbourated internal combustion engine the same way gasoline or diesel would be otherwise. A great (or some might say, ridiculous) bonus of this path is that you can see the process quite clearly on almost cars fitted with the system.
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But what about the vehicles themselves? Producers of the early 1940’s, interestingly, were not just cars and pickup trucks; motorcycles and water transport were involved in this wood-fueled rennaisance, too, not to mention buses and other means of public transportation. For some of these applications, it wasn’t exactly the best power source; as Low Tech Magazine’s in-depth analysis of the subject points out, gasoline and other modern-day standards for vehicular propulsion are monumentally more powerful than chopped-up trees - in some cases, by a factor of ten.
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Combined with the extra weight of the metal chambers and the dreadfully low amount of energy contained in a kilogram of wood gas (5.7 megajoules) versus a lighter and more powerfully-fueled gasoline and diesel cars (each roughly 43 MJ/kg), you’d expect these antiques to be slow - and by modern standards, they were. But in parts of Europe during the 1940s, these vehicles were lauded for their range (again, by modern standards, very short). Unlike petroleum-fueled cars and trucks, the fuel for which was more complicated to make, producers could be fueled almost anywhere, so long as the driver carried an axe. This, combined with the fact that most cars at that time weren’t that much faster, meant people adapted quickly to using producer gas vehicles when the situation required it.
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But we shouldn’t expect these vehicles to be all that environmentally friendly themselves, as burning large amounts of wood or coal on a daily basis is not exactly a harmless alternative to fossil fuels - not to mention the risk of deforestation (you think we’re low on oil?). Still, pure chopped wood doesn’t necessarily require the same refinement and transport procedures we apply to fossil fuels every day.
Plus, in a pinch, wood gas cars are an excellent and dependable means of transportation when there is no alternative.
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