Until the early 2000s there had been a long period of cheap fossil fuel sourced power. While power was so cheap, the anaerobic digestion process was largely ignored in the west. China and India and some other nations realized its value especially to subsistence farmers, and developed early versions of the now increasingly popular buried, fixed dome, household and small community biogas digester systems which they invented. Ever larger numbers of these affordable energy plants are now being built and operated, so that by 2016 literally millions of people will be benefiting from the “biogas renaissance”.
In the western nations during the first half of the 20th century, anaerobic digestion had been popular among the water boards, and municipal corporations in charge of the safe disposal of sewage sludge, but almost all of those had, by then, been replaced by incinerators. Energy was so cheap that even those running those incinerator plants failed to truly realize that they were using energy, to destroy energy! That was an expensive waste, which is now being put right as large numbers of sewage sludge incinerators are being shut-down and replaced with biogas plants, the latest of which can be so efficient in making power that they can generate enough electricity to run the entire wastewater treatment works (sewage works) solely using the sludge from the works as their bio-fuel!
These are just two examples of the way that the anaerobic digestion and biogas industry is now growing. The word is out now, and even if fluctuating oil prices slow growth a little through 2015, expect to see more and more biogas plants wherever you go!