Biogas methane is the opposite of carbonaceous methane which is methane created from fossil fuels many thousands of years ago. So, in other words it is recently created, biologically produced methane made from renewable organic matter. It is also by definition man-made, made in a biogas plant, and it is the one great future raw material for building a sustainable world from which all others will come, which can still create and consume all the synthetic organic materials we find so essential to our lifestyles in the modern world.
The need to distinguish methane gas derived methane from fossil fuel which also known as natural gas, has brought the term into use, and I think you should know it as it will become more and more important to society as the years go. This will happen as oil, gas and coal extracted from mineral deposits begin to run out. By running out I mean that extracting the remaining fossil fuels will largely become too energy expensive to collect, due to all the easy reserves becoming depleted.
Natural gas comes from the world's mineral reserves, where it has been stored in the ground since its formation from prehistoric living plants and animals. Large quantities of natural gas/methane also seeps out from old oilfields, coal mines and coal measures which wastes a lot of natural gas which as soon as it enters the atmosphere is lost to man's use.
In fact methane which enters the atmosphere is thought to be a very potent cause of greenhouse warming. Methane is something like twenty times more active in absorbing the sun's heat, and causing global warming, than carbon dioxide.
But, believe it or not man can keep creating biogas methane forever as long as he keeps re-growing more crops to produce more biogas methane and uses it by burning it before it escapes, because those crops will suck the carbon dioxide produced by burning back out of the air, and the system remains stable.
Biogas methane is produced in biogas plants, although strictly these are properly called anaerobic digestion plants.
This renewable and sustainable methane is a basic simple organic molecule building block from which engineers and chemists will for thousands of years create all the wonderful organic material based substances we need in our modern lives. Not only can (and will) biogas methane be used to replace oil as the initial feedstock for all our energy needs, if made in big enough quantities it can be used to satisfy all plastic and carbon based materials needs, including for pharmaceutical and transport fuels.
Thinking more about building a digester to produce biogas methane? Steve Last is web master for the fact filled Anaerobic Digestion Community web site where much more biogas methane information is available.
Steve Last is also a regular contributor of dog breed related articles at The Dog Breed Compendium.