Thrive
Energy released their gasifier system as an open source project. Their design uses small (US typical) sized
wood pellets and was originally designed and is used for small generators and engines 400-700cc. It has long run times, tar
free operation and the grateless design avoids numerous issues common with gasifiers. The
video was just posted on assembly of a no-weld kit that is for sale that contains all the hard to make (if you don't have a metal shop), parts.
I have followed
wood gas for years, and this is a pretty neat simple system especially for off-grid and you don't want to mess around with wood prep. I am looking at getting one for a ceramic kiln, and a foundry as well as backup generation.