Environmental and economic assessment of decentralized bioenergy and biorefinery networks treating urban biowaste

The decentralization of waste management argues to support better planning, fair distribution of material and economic resources, and increased citizen participation. This study aims at assessing the environmental and economic performance of a decentralized biowaste management system, using the frameworks of life cycle assessment and net present value analysis. Five scenarios are designed to reflect the transition from an energycentered biowaste management (scenario 1) towards a novel biorefinery system (scenario 2) and its expansion to a decentralized network (scenarios 3, 4, and 5) of small-scale plants treating urban biowaste. The global warming potential of the energy-centered system is 134 kg CO2 eq, while the biorefinery system offers mitigation of the global warming by -4324 kg CO2 eq t 1 biowaste treated. The decentralized network designed to capture 20% of the urban biowaste generated in Lyon Metropolitan (S5) provides environmental (S5a: -1983 kg CO2 eq, S5b: -1992 kg CO2 eq) and economic (S5a: 491_, S5b: 475_) benefits, especially when collection is performed with electric bikes (S5b) and the bio-products substitute resource and energy intensive equivalents in the market. Collection with electric bikes contributes to a low-carbon economy while significantly increases labor costs. The transition towards a bio-based economy can transform biowaste management into novel cascading biorefineries of multiple high-value products. Resilient and optimized system design can support low carbon economies and increase employment while being economically sustainable.