Wood gas is an interesting idea for a source of power using modified IC engines. It is usually mostly CO and that is not only a poison but an area with a small percentage of the gas will in time build up a harmful dosage. Most attempts to use it have encountered problems filtering the gas to remove water and other contaminants. A second problem has been damage to the engines due to impurities in the gas causing rusting, tar formations and other damage to the engine. The heat tended to damage the gas generator unit and the filters plugged up. While not as dangerous as a steam boiler, they are more complex. They are not a replacement for wind, solar, or hydro power, but it may supply a useful source of backup power when those items are not available. While bio diesel may be more effective, a wood gas system does not require any inputs but wood. The systems shown below have given up some of the total energy available in wood and run off charcoal. While less efficient, charcoal is much easier to filter and its gas is much more uniform. It can be made more efficient, but more complex, by adding steam to the air for the engine. Go down to the bottom two if you just want to see an old man playing around quite well with his "toys". Video work is horrible, content is priceless There is series of videos on you tube on how to create a wood gas system that I liked. It was as much fun to watch his construction process as the actual product he made. He is an excellent craftsman, welding area, and an absolute master of using off the shelf items as well as inexpensive tools to cut and shape the metal as using magnetic welding holders and his welding table to make ad hoc jigs to position the material to be welded. He has not really completed any totally operational generators, but has addressed more of the problems than a lot of the technical articles have. The first thing he addresses is that if you use wood for fuel for your gasifier, when you start the process you have to burn off the moisture in the wood as well as the tars, etc. Thus he decided to run it on charcoal for both a cleaner and more uniform gas. Much longer time between cleaning your filters. Thus his first plan if for a way to make charcoal. He ends up with the best system I have seen yet to make charcoal. It creates hot water, and the method shown would work well if used for any wood stove modification, dry wood for the next batch of charcoal, as well as using the gasses produced in the charcoal making to heat the charcoal retort. While he starts it off as an after thought. I think it is well worth a stand alone as part of the whole concept. Here is the next stage where he creates a much larger and much more expensive charcoal retort that can also be used to produce the gas a well. I liked it better for the ideas he used to manufacture the unit. Saw many good tips on making excellent wood stoves, perhaps a source of heat for a still etc. Would have to be done before TSHTF, costs more money, and takes more tools to build it. I wouldn't or perhaps couldn't have built it but it much closer to what you would see in a commercial unit When you have the charcoal, it needs to be burned under the right conditions. Here is one of small batch units running what appears to be about a 3 or so hp engine. All spread out and in the test phase. Good information on building and on his results. And again here is a much more advanced model, works better, further down his design path, but harder to build and costs more money. Does increase efficiency by adding steam which means the gas will , like the old gas used in the 1890's in the cities, have hydrogen as well as CO2. More power out of the engine. This is my favorite charcoal gas video. The picture quality is very bad, the camera work is horrible, there is very little detail. It is just an old man who took his old Gravley tractor and converted it to charcoal gas and so far has about 10 hours on it mowing his lawn. No math, no Auto Cad, not even some one else to help hold the camera. If TSHTF I think he would be a lot more useful than your average bear as Yogi Bear said in the cartoons. I think you could take his simplicity and some of the more complex designs above and come out with a very workable system. His tractor may well be 40 years old. They quit making the 2 wheel version in 2002.
