Utilizing a CHP Power Plant’s Energy and CO₂ Emissions for the Manufacture of Affordable and Carbon Neutral Algae Bioplastic for Re-Useable Packaging

The short lifespan and lack of sufficient recycling systems for plastic packaging like PET water bottles leds to higher fossil hydrocarbon extraction, carbon emissions, and environmental pollution. Manufacturing bioplastics like polylactic acid (PLA) and bio-polyethylene (bio-PE) are 2 strategies being promoted in the European bioeconomy along with recycling. However, research is lacking on the carbon neutrality of producing microalgae bioplastic packaging and its recycling. This study aims to determine the techno-economic feasibility and carbon footprint of scaled microalgae bioplastic bottle production through a joint-venture project with a bioenergy plant. 3 scenarios were evaluated for their financial viability and carbon neutrality. In scenario 1, algae sugars are converted into biogas for bioenergy. In scenarios 2 and 3, the microalgae sugars are transformed into PLA plastic pellets and bio-PE plastic pellets, respectively. The life cycle analysis of scenarios 2 and 3 was also extended for plastic bottle manufacturing and recycling. The results show that the algae plastic biorefinery is highly reliant on the bioenergy producer’s electricity and steam heat sales to cover its capital and operational costs. While scenario 1 was financially viable, scenarios 2 and 3 were limited at larger scales. Recycling the PLA and bio-PE resulted in higher CO₂ savings than other end-of-life options like disposal and other biomass feedstocks. This study seeks to provide resources and insights about the strengths and weaknesses of algae bioplastic production for single-use plastic bottles.