The integrated biorefinery concept
Are algae a valuable biomass resource for large scale production of biofuels? As part of the research community, we are still working to give a complete and clear answer to this question that is inspiring research institutes and companies from all around the world.
Without any doubt, algae are a valuable biomass due to their high content in proteins, lipids and carbohydrates that can be converted into fuels (e.g. biogas, biodiesel, bioethanol). In the last few years, this potential energy has been investigated on the details producing a number of high quality publications highlighting pros and cons of the algae biofuels production process. Here are the top four issues:
- high biomass production costs;
- inefficient harvesting technologies;
- energy intensive downstream processing;
- negative overall energy balance.
In other words, the process is still far away from being able to produce and process enough algae biomass to obtain any algae-fuels able to compete with the market price of other fuels/biofuels. Even in the most positive scenarios, on the short term, the direct production of biofuels from algae is a non-economical option, However, when considering the algae-biofuels as part of a more complex and articulated production chain where first the biomass is processed to extract high valuable products (high market price), and then the residues are converted into fuels, the economics of the system start to be promising. This is the integrated biorefinery concept.
Focused on macroalgae collected and cultivated in Norway by SINTEF, the project at Scandinavian Biogas Fuels AB, Linköping (SE), is contributing to prove this concept looking by intvestigating long term digestion performances. Working on continuous digestion trials, the project tests different operational conditions and algae substrates to simulate full scale AD plant performances and different algae processing strategies.
“Benefits of combining anaerobic digestion and amino acid extraction from microalgae” in Chemical Engineering Journal by Ramos-Suárez et al., 2014. DOI:10.1016/j.cej.2014.07.086
“Techno-economic assessment of biofuel development by anaerobic digestion of European marine cold-water seaweeds” in Bioresource Technology by Dave et al., 2013; DOI: 10.1016/j.biortech.2013.01.005.
Francesco Ometto, ATBEST Researcher, Scandinavian Biogas Fuels