Implementation of waste-to-energy options in landfill-dominated countries: Economic evaluation and GHG impact

The economic and environmental impact of several waste-to-energy (WtE) schemes to produce electricity from municipal solid waste (MSW) refuse is evaluated and compared with landfill disposal. Both incineration and gasification alternatives are considered. The gasification option includes three different configurations: (1) a fluidized bed gasifier (FBG) with internal combustion engine (ICE), (2) a FBG with organic Rankine cycle (ORC) and (3) a grate gasifier with steam Rankine cycle (SRC). The study is primarily applied to regions where the management system is based on Mechanical Biological Treatment (MBT) plants, generating a large share of refuse (>70%), which is currently landfilled. The specific case of Andalusia, a region in the south of Spain with 23 MBT plants distributed over a region of 87.000 km², where about 80% of municipal solid waste (MSW) is currently landfilled, is taken as main reference; thereafter, the study is further extended to preliminary assess other regions of some European landfill-dominated countries with similar characteristics. The results show that both incineration and gasification improve landfill disposal, contributing favorably to greenhouse gas (GHG) reduction and fulfilling EU environmental regulations, although the three gasification options analyzed yield lower GHG emissions than incineration. In addition, gasification enables better integration of WtE into existing MBT plants, especially in the particular case of Andalusia, where MBT plants are widespread on the region, making it a more promising option than incineration, which is mainly based on large centralized plants, and less socially accepted. From the options analyzed, the WtE scheme based on FBG with ICE gives the highest profitability for a given gate fee, due to much higher electrical efficiency. However, FBG with ORC seems to be a better option in the short-term for landfill-dominated countries, due to its higher technical reliability and the low gate fee currently available in these countries.