Pale purplish-red, quickly degenerating when removed from the water and becoming distinctly orange; fronds bushy, with a cylindrical axis to1 mm wide and 200 mm long. Both phases readily reproduce vegetatively. Photographs by M.D. Guiry
The central objective of this paper is to evaluate the production of biogas by the substitution of energy crops with marine macroalgae: mixture of brown (20%) and red algae (80%) as feedstock in an industrial scale biogas plant. This plant operates with the co-digestion of maize (27%), grass (54%), rye (8%) and chicken manure (11) and produces 500 kWh energy. In order to assess environmental friendliness, a life cycle assessment was performed by using the software Simapro. Potential environmental impact categories under investigation were global warming, acidification, eutrophication and land transformation potential. Our results determine the affirmative impact of the codigestion of algae with chicken manure on the emission reductions: 52%, 83%, 41% and 8% lower global warming, acidification, eutrophication and land transformation potentials, respectively per 1 MJ of energy generation, moreover, 84% and 6% lower acidification and land transformation potentials per kg of feedstock.