If you want free fuel for your home and you have a ready source of manure (any kind even human) and plant matter you can have free fuel that can be used just like propane and Natural Gas.
I designed and built a solar batch methane generator out of two old barrels and salvaged plumbing. It produces enough methane to run a stove for an hour each day or 3 gas lanterns continuously. I now have a six barrel system that runs a converted generator for electricity to run my workshop 3 hours a day.
Methane can be used in NG appliances without any change and propane appliances with a larger NG orrifice.