The work in the ALGAESOL project started with establishing the technical, sustainability and system foundations for developing solar- and algae-based biofuels for shipping and aviation. Fuel quality requirements were defined, suitable waste and carbon dioxide streams as inputs for bioelectrochemical and electrochemical processes were identified, process flow and component interfaces for system modelling were specified, and the methodological framework for the sustainability assessments were set.
In the ALGAESOL project, two parallel routes are being developed: 1) the direct solar conversion pathway, using photo(bio)electrochemical technologies, and 2) the microalgae-based conversion pathway, where bioelectrochemical technologies are directly linked to microalgae production. Route one encompasses two main pathways: i) photo-bioelectrochemical (P-BE) production of methane gas, and its purification process, and ii) photo-electrochemical (P-EC) production of methanol, and its purification process.
During this reporting period, work has advanced on the development of photoelectrodes for sunlight harvesting. Various scalable fabrication routes have been explored and optimised, leading to improved performance, fewer defects and higher photocurrents. Moreover, the cathodes for the electrocatalytic and bioelectrochemical processes have been developed and are being optimised, showing stable performance for over 100 hours, increased efficiencies and high production rates of methane and methanol.
With regard to the microalgae-based conversion pathway, work has focussed on improving Chlorella sorokiniana strains towards increased lipid productivity, microbial contamination control strategies, as well as combining the photo-bioelectrochemical production of acetate with the mixotrophic production of C. sorokiniana. This lipid-rich biomass has been subsequently tested in newly developed microfiltration membranes for pre-concentrating the algae solution and thereafter used for the development of novel lipid extraction technologies. In the next reporting period, the side stream generated after the lipids have been extracted from the microalgal biomass will then be tested in an anaerobic digestion process, connected to a bioelectrochemical technology to increase methane production. Moreover, the processes for turning the intermediate products into the end-products: fuels for aviation and shipping, will be developed in the next reporting period.
Finally, the data collection for the process modelling and process simulations as well as the sustainability assessments has started. This will allow to develop and model scale-up strategies, demonstrate the performance of the ALGAESOL integrated systems and implement and virtually demonstrate the viability of the project solution within use-case scenarios for aviation and shipping, and evaluate the environmental, economic and social sustainability of the proposed technologies, innovations and products developed.
