Techno-economic feasibility and environmental sustainability of waste-to-energy in a circular economy: Sri Lanka case study

Abstract

Many countries in Asia-Pacific region have programs in place for clean energy transition aligned with their Nationally Determined Contributions. However, in most of these countries waste-to-energy (WtE) has no major role in the current programs. The study presented in the paper has examined WtE in a circular economy as a solution that can have economic, financial, social, and environmental co-benefits through efficient use of natural resources, reduced emissions, and fostering innovation. The case study involving Sri Lanka has shown that similar countries have the potential to implement WtE projects coupled with appropriate circular economy elements with adequate financial and economic returns. The results show the viability of a centralized incineration plant of 500 tons/day capacity and decentralized biogas facilities of 150–200 tons/day capacity for each of the three districts in the country's Western province. The estimated total power generation capacity from incineration is about 20.3 MW and the annual exported electricity is 129.86 GWh. The estimated power generation capacity of the biogas plants is about 7.16 MW, and the annual exported electricity is about 41.4 GWh. The total amount of compost produced is estimated to be about 43,000 tons/year by processing digestate and 125 tons of recyclable waste expect to be recovered daily. The proposed development plan positively impacts the grid emission factor of the country and the estimated avoided annual GHG emission is about 380,000 tons of CO2. This pioneering case study can be used as a basis for immediate action to solve waste management issues within a circular economy helping similar economies in the Asia Pacific region in their efforts to achieve net zero emission target by the middle of this century.