NOVELTY - The system comprises: growing trays containing water and a polyculture of aquatic plants; a harvesting system arranged to harvest a portion of the biomass contained in the growing trays; and a gasifier (142) comprising a pyrolysis chamber (146) and a combustion chamber (148), where the pyrolysis chamber is arranged within an interior of the combustion chamber. The growing trays are arranged: to continuously receive water, carbon dioxide, air and nutrients until a biomass is produced; in a vertically stacked orientation with a space between each adjacent growing tray.    USE - The system is useful for producing a biogas (claimed) including a methane containing biogas that is useful as a fuel for heating and in drive steam turbines for the generation of electricity.    ADVANTAGE - The system is capable of efficiently producing the biogas without waste products in an economical manner.    DETAILED DESCRIPTION - The system comprises: growing trays containing water and a polyculture of aquatic plants; a harvesting system arranged to harvest a portion of the biomass contained in the growing trays; and a gasifier (142) comprising a pyrolysis chamber (146) and a combustion chamber (148), where the pyrolysis chamber is arranged within an interior of the combustion chamber. The growing trays are arranged: to continuously receive water, carbon dioxide, air and nutrients until a biomass is produced; and in a vertically stacked orientation with a space between each adjacent growing tray. The pyrolysis chamber and the combustion chamber are concentrically arranged, where the pyrolysis chamber comprises coiled tubes (150). Each coiled tube has a diameter of 1-2 inches, and a straight length of 22-27 feets. The pyrolysis chamber is maintained at a temperature of 1200-1800 degrees F.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic elevational view of a gasifier.    Gasifier (142)    Pyrolysis chamber (146)    Combustion chamber (148)    Manifold (149)    Coiled tube (150)    Hydraulic piston rams. (170)