Biogas Home Energy Generators - DIY

I've always been interested in living off the grid, but want to maintain some of the benefits of industrial living like hot water, home heating/cooling, indoor plumbing and lighting while avoiding some of the problems like water and air pollution and deforestation from burning wood and keeping animals.
As a vegetarian, I thought for 30 years that I could build a cordwood envelope house that would heat and cool itself and allow me to grow fruits, nuts and vegetables year round, the garden serving as the engine for heating and cooling and maybe even lighting.
Seemed pretty nifty.
After awhile it seemed that this idea might not be sufficient and that it would be good to have other means of producing energy for these tasks.
Also, I'm no longer vegetarian and see that in an ideal condition I would raise my own meat and dairy animals and also have to provide for their feeding and productively disposing of their wastes.
I was very impressed by people who were making very effective hot water heaters out of compost piles.
I had heard years ago of people who used compost, such as soiled straw from the horse barn, etc. to produce methane that could be used for heating, cooking and running machinery and fertilizer for gardening.
Recently I came across this information on something similar and more effective than sticking a pipe into a pile of rotting hay, though it is almost as simple.
Although these projects use manufactured materials in their construction, they could be made from natural, found materials though I suspect the efficiency of the units are likely higher with the manufactured parts.
The project described first can be built in a couple weeks [one week is for cement curing] for about $1,200 while the second one, built in China - runs about $450 but due to materials that degrade requires more maintenance.
I recommend that you also read the articles in the links at the end of this article; one of which describes how these generators have been used for decades in China and shows how they are constructed.
For some reason this article will not post properly here.
Please follow the link to read it.
http://www.motherearthnews.com/renewable-energy/home-cookin-with-homemade-biogas-energy.aspx#axzz2NEcqq0yG