Wood Gas is a vaporous 'syngas' fuel made from baking of wood at high temperatures with a controlled amount of oxygen or steam. Wood Gas is primarily made of Carbon Monoxide and Hydrogen, which make up the majority of flammable elements. The rest is made up of inert Nitrogen and traces of Methane, Carbon Dioxide, and Oxygen.
Wood gas is primarily used as an alternative or replacement fuel in spark-ignition vehicles, where the gas is piped directly into the engine with very little or no modification to the vehicle itself.
Wood Gas could be burned as a cooking or heating fuel, but when comparing the benefit of wood gas versus the effort involved, it is more practical to simply burn wood itself for these purposes.
Wood Gas systems have seen widespread use in the past, when petroleum products were scarce or heavily-rationed by government bodies. Australia in particular had resorted to this system during World War II, when Petrol (gasoline) was being rationed to 40 miles a week in the 1940's. A joint effort between the Ford Motor Company, the University of Melbourne, and Powell Gas Producers had all but eliminated Australia's dependence on petrol.
Making Wood Gas
Wood gas is made in a large burning chamber called a 'gasifier', where the flow of air can be controlled to char the wood and convert it into wood-gas, rather than simply burn the wood itself. Several gasifier designs have made available, both in print and on the internet, and are often designed to be as simple and cheap to build as possible.
The United States Federal Emergency Management Agency (FEMA) released a report to the public, which includes a set of Wood Gasifier plans as part of their on-going efforts to prepare and educate the public about disaster preparation -- a link to said plans has been provided below. The report also includes instructions for operation, care and maintenance of the gasifier once the device has been constructed.
While material for producing gas is plentiful in most parts of the world (anywhere some form of tree or suchlike grows) there are certain shortcomings to using wood gas:
- Wood Quality: The 'greener' or damper the wood is, the less wood-gas it will produce.
- Warm-Up: A gasifier must be run for several minutes before it can properly provide fuel to the engine.
- Modification: Most vehicles these days operate using a fuel-injector, rather than a carburetor. Newer cars may need some modification to run on wood gas.
- FEMA - Simplified Wood Gas Generator Plans (1.9MB PDF File)