The potential of microalgae as feedstock for methane production is evaluated from a process technical and economic point of view. Production of mixed culture algae in raceway ponds on non-agricultural sites, such as landfills, was identified as a preferred approach. The potential of straightforward bio-methanation, which includes pre-concentration of microalgae and utilization of a high rate anaerobic reactor was examined based on the premises of achievable up-concentration from 0.2-0.6kgm-3 to 20-60kg dry matter (DM)m-3 and an effective bio-methanation of the concentrate at a loading rate of 20kg DMm-3d-1. The costs of biomass available for bio-methanation under such conditions were calculated to be in the range of z€86-z€124ton-1 DM. The levelized cost of energy by means of the process line "algae biomass - biogas - total energy module" would be in the order of z€0.170-0.087kWh-1, taking into account a carbon credit of about z€30ton-1 CO2(eq).
Bibliographical noteFunding Information:
This work was supported by the Institute for the Promotion of Innovation by Science and Technology-Strategic Basic Research (IWT-SBO) Sunlight Project –Lipid-based, high value products and renewable energy from microalgae grant 80031 and Ghent University grant 179I16D9W . This work is part of the Ghent University Multidisciplinary Research Partnership (MRP) –Biotechnology for a sustainable economy (01 MRA 510W). We thank Nico Boon, Tom Van de Wiele, Siegfried Vlaeminck for the useful suggestions and Jan Arends, Sofie Van Den Hende and Jinxing Ma for critically reading the manuscript.
- Anaerobic digestion
- Techno-economic analysis