The greenhouse environment enables complete control of soil matrix, humidity, lighting & temperature. About a decade ago, an anaerobic treatment process was developed and patented that was capable of degrading lignins and thus producing about twice the volume of methane gas as other digesters. Just take a close look at the following video about a waste to energy engineering plant London, UK. There is some added animation to explain the process of generating electricity from waste more clearly.
“Waste-to-energy” programs were thereafter developed for municipal solid waste, beef, dairy, swine, turkey, broiler, and layer production wastes; food processing wastes; agricultural solid and liquid wastes; and high organic strength, industrial liquid, and solid wastes. In each instance, the five co-products of methane, CO2, organic fertilizer (digestate), liquid fertilizer concentrate and reverse osmosis permeate water would be produced for subsequent marketing to the commodity marketplace.