From biorefinery landfills towards a sustainable circular bioeconomy: A techno-economic and environmental analysis in Atlantic Canada

Abstract

Recycling and upgrading of low-grade materials plays a pivotal role in building a sustainable circular bioeconomy. The present study explored the potential of energy recovery from biorefinery landfills by means of in-situ thermal processing of municipal solid waste (MSW) with a techno-economic analysis and using RETScreen clean energy project analysis software. An environmental assessment was performed to validate the sustainability of the proposed process. The biorefinery landfill uses existing MSW landfill infrastructure to move from a disposal-only paradigm to a product-creation paradigm. This innovative concept can reduce the extra costs of ex-situ conventional power plants by avoiding waste transportation to a secondary site. A case study in Atlantic Canada was employed to optimize energy reclamation from MSW via two principal pathways: (1) Rankine cycle steam power plant and (2) gas turbine. A plant with a 30 t h−1 capacity and 2 MW power production was proposed as a base case. The results indicated that the gross reduction in annual greenhouse gas emissions was 1115 t CO2 greater for a gas turbine than a steam cycle. Further, for a steam power plant, the capital cost was approximately three-fold higher, and the operating and maintenance costs were nearly eight-fold higher than a gas turbine plant. Study results will encourage progress towards a sustainable biopower system and lay the foundation for comprehensive analysis of renewable resources like MSW. The key outcomes of this study target growth of the circular bioeconomy. Moreover, they can serve as the basis to draw recommendations on the techno-economic feasibility of implementing such biorefineries, specifically at high latitudes where energy costs are relatively high.