Assessment of waste-to-energy strategies for municipal solid waste landfills in Chennai: A case study using energy-economic-environmental (3E) approach

The utilization of municipal solid waste (MSW) for energy production has been widely adopted across the globe for several decades. In contrast, Chennai city continues to rely heavily on landfilling for MSW disposal, with Kodungaiyur and Perungudi being the city's two major dumpsites. Given the growing concerns over greenhouse gas (GHG) emissions and diminishing availability of land, there is a pressing need to explore sustainable alternatives for solid waste management in Chennai.

This study evaluates the energy, economic, and environmental (3 E) feasibility of implementing Waste-to-Energy (WtE) technologies at the Kodungaiyur and Perungudi landfill sites in Chennai. Eight technology scenarios, including Landfill Gas Recovery Systems (LFGRS), Anaerobic Digestion (AD), incineration, gasification, and their hybrid combinations, are preferred. AD demonstrated Anaerobic Digestion (AD) was identified as the Pareto-optimal solution for Chennai's 3 E nexus, offering the best balance between energy recovery, economic returns, and environmental performance. AD achieved the highest energy recovery, generating output and producing up to 492,712 m³/day of biogas and 1034.69 MWh/day of electricity. Economically, it delivered net profits ranging from 31,397 to 159,964 USD/day, supported by revenues from electricity, district heating, and fertilizer. Environmentally, AD demonstrated strong climate benefits, with net emissions reduced to 136.36 tCO₂/day, compared to the landfill, which emits an average of 2452 tCO₂/day from AD and conventional landfilling. The hybrid LFGRS & AD achieve substantially lower net emissions, with AD averaging −136.36 tCO₂/day. The scenario also performed well, offering a practical balance across all dimensions. These results underscore AD's potential as a scalable and LFGRS & AD averaging 259.24 tCO₂/day, demonstrating strong climate benefits, which also enables digestate recovery and a sustainable WtE strategy for urban solid waste management in India.