The potential of aquatic weed as a resource for sustainable bioenergy sources and bioproducts production

Abstract

Developing carbon-neutral bioenergy sources and bioproducts is an extraordinary opportunity for achieving an environmentally friendly economy. However, the overconsumption of resources in bioenergy and bioproduct production causes severe environmental concerns. The green biorefinery concept is one of the most attractive solutions for sustainably producing bioenergy sources and bioproducts. Seaweed is well-known as a promising green resource for biorefineries. Biorefineries based on seaweed not only produce various products but can also help solve macroalgal bloom issues. Nevertheless, a comprehensive environmental investigation should be performed before implementing seaweed-based biorefineries. Thus, using an environmental life cycle assessment, the current study examines three seaweed-based biorefineries. These scenarios include biogas production and waste valorization (Sc-1), bioethanol production and waste valorization (Sc-2), and biogas + bioethanol production and waste valorization (Sc-3). The results indicate that all the proposed scenarios offer environmentally friendly solutions for utilizing seaweed as a source of bioenergy and bioproducts. Sc-1 demonstrates the best environmental performance compared to the other two scenarios. Specifically, Sc-1 achieves a 99% and 97% reduction in total weighted environmental impact compared to Sc-2 and Sc-3, respectively. This finding is attributed to the avoidance of mineral fertilizers in Sc-1, resulting in a significant reduction in environmental impact. The electricity generation based on Sc-1 results in 1.91E-08 DALY/MJ of damage to human health and 1.65E-03 PDF.m2.yr/MJ of damage to ecosystem quality. Furthermore, the net weighted environmental impact of electricity generation based on Sc-1 results in 1.65E-03 EUR2003/MJ of damage, compared to 1.07E-01 EUR2003/MJ for grid electricity in the region. Therefore, replacing grid electricity with electricity generated from biogas in Sc-1 can reduce 98% of environmental damage.