NOVELTY - The device for producing algae biomass, comprises a methane-steam reformer that produces carbon dioxide as byproduct, means for collecting the carbon dioxide that is obtained from the methane-steam reformer, a means for transporting the collected carbon dioxide to an algae cultivation plant, a means for introducing the transported carbon dioxide into algae biomass production process in the algae cultivation plant, and further means for removing of impurities, means for adjusting temperature and pressure, and means for harvesting the biomass, which is produced in the algae cultivation plant.    USE - Device for producing algae biomass useful for industrial application such as biofuels, a chemical intermediate, a dietary supplement or pharmaceutical.    ADVANTAGE - The device ensures economical, rapid and large production of algae biomass in an environmentally friendly manner.    DETAILED DESCRIPTION - The device for producing algae biomass, comprises a methane-steam reformer that produces carbon dioxide as byproduct, means for collecting the carbon dioxide that is obtained from the methane-steam reformer, a means for transporting the collected carbon dioxide to an algae cultivation plant, a means for introducing the transported carbon dioxide into algae biomass production process in the algae cultivation plant, and further means for removing of impurities, means for adjusting temperature and pressure, means for harvesting the biomass, which is produced in the algae cultivation plant, and means around the harvested biomass for the industrial application. The means for collecting is a container or tank. The means for transporting the carbon dioxide as by-product comprises a tank (40), truck, a section or a pipeline. The algae cultivation plant is an open-pond-device or a closed photobioreactor device. An INDEPENDENT CLAIM is included for a method for producing algae biomass.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a method for producing algae biomass.    Steam methane reforming-process chamber (10)    Gas pipeline (20)    Flow supply (30)    Tank (40)    Algae cultivation process. (50)