Biogas is a naturally occurring gas, that is a waste product of a specific type of methane-producing bacteria. These bacteria can be present in many places, including the human body, swamps, landfills, and cows. Methane is a highly flammable, low energy density gas that is extremely easy to produce. In fact, almost every person produces methane on a daily basis without even thinking about it. The keys to efficient methane production, however, require forethought and special attention to the needs of the bacteria.

Methane can be made from anything, and it is because of this that it is a common product of many farms around the world. Waste from other biofuel processes can be used, as well as manure from humans and animals, food wastes, agriculture residues, and just about anything that was living at one time or another. Mix the feedstock with some water, and keep the oxygen away, and you'll likely produce biogas without much effort. The amount of biogas will depending on the feedstock and its composition. You are looking for a carbon to nitrogen ratio of about 30:1. Thats 30 browns to each green by weight, which coincidentally is the same perfect ratio for an aerobic compost heap.

Temperature plays a big role in the formation of methane. These bacteria thrive in the bodies of animals, so they have evolved to survive in warm, moist, zero oxygen environments. The most efficient temperatures are from 90-110 degrees F (32-43 C). So, to obtain the most bang for your dung, you will need a heating system, or at the very least, a way to keep the temperature constant.

The basic layout of a methane production plant or digester is input from one end, output from the other. What is the output, you might ask. Well, actually it is compost, and quite good fertilizer at that. The methane is not a direct output, but rather a byproduct of the bacteria.

Methane can be stored in large, low pressure containers, which are safe and easy to construct. But, in the interest of space and energy density, it can also be compressed. But care must be taken to avoid putting oxygen with the compressed methane, because that can go BOOM. Compressed methane can be used in vehicles, (Compressed Natural Gas or CNG), or can be used similar to natural gas or propane in stoves or other gas appliances. Stationary applications, like stoves, are where it has the highest value for a homestead, and by creating a simple, low-pressure pipeline (PVC or black poly), you can take the biogas directly from tank to appliance with little effort. Of course, you will want some safety features like flashback arrestors, pressure guages, valves, and the like, but any natural gas fixture can be used, and they are readily available.

Because of its ease of use and production, methane is one of the most vaulable biofuels you can produce at home. And because it is a greenhouse gas that is 21 times more damaging than CO2, every house and homestead on the planet should be campturing and using this free resource.