Algae-Centred Industrial Symbiosis

Abstract

This thesis describes a unique industrial symbiosis employing algae at the core of a novel industrial system that integrates fossil-power generation, carbon capture, biofuel production, aquaculture, and wastewater treatment. A new modelling framework capable of designing and evaluating material and energy exchanges within an industrial ecosystem is introduced. Results, focusing on CO2 flows, demonstrate the potential for CO2 emissions reduction through carbon reuse and recycling. Significantly, this thesis shows the positive potential of this new complex industrial symbiosis and of the modelling framework by demonstrating a high degree of flexibility in terms of integrated material and energy flow analysis. Details of this algae-centred eco-industrial park and a demonstration of its workings through preliminary techno-economic calculations are presented. Results show that a proposed eco-park that generates 660 MW power plant and several material co-product streams (biofuel, chemicals), reduces net CO2 emissions significantly by 62% (equivalent to 1,9 million t/yr) as compared to a 660 MW stand-alone power plant. This reduction is achieved through the recycling and utilisation of captured CO2 in the algae feed. Using a 100% renewable option, zero CO2 emissions may be targeted, but noting that this option is limited because it comes without materials co-production. Also, the overall unit production cost of algae-centred eco-industrial park proposed significantly lowered by 60% compared to the overall unit production cost needed from combining all stand-alone plants together. Feedstock and equipment overall budgets have more impacts compared to other sensitivity analysis carried. The effectiveness of evaluating energy technology transitions towards future low-emission energy and chemical systems is discussed.