The process of “cooking” wood to release combustible gases, including Hydrogen, Carbon Monoxide, and some Methane, is well documented. It was a common occurrence in Europe during the second war, and found applications here in the US, and other places around the world. The following is a video demonstration of such a process, and a list of resources for further study, that will enable you to build (or buy) and operate your own gasifier. You can operate a generator, vehicle, or other engine driven piece of equipment (spark ignition or diesel), and heat is a valuable byproduct. As you can see from the demonstration, once gasification starts, emissions are extremely clean.