## 5 Conclusions  
This paper presents a multi-criteria decision analysis approach to evaluate different thermal gasification techniques for municipal solid waste. The different options prioritized during the evaluation of the gasification technologies are based on the different attribute values collected for the specific gasification technologies from the preliminary research. For the non-recycling and recycling scenarios, the study ranks the thermal gasification techniques based on their technology performance indicators, economic performance indicators, environment performance indicators, fuel requirements, and attribute values. The selection of a specific gasification technology for an overall economic, energy, and environment purpose is a challenging task; thus, a sensitive decision-making strategy is required based on the available input factors to meet the different requirements of the gasifier. This study uses a decision matrix to standardize the criteria and sub-criteria related to the thermal gasification techniques for MSW. The entropy weight method by [PERSON] is used to determine the weight of the criteria and sub-criteria. This study adopts five weighting scenarios, and the closeness to an ideal solution for each alternative thermal gasification technique for a given criterion and the alternative thermal gasification technique rankings are determined. Though the entropy weight method adopted using the MCDM approach is straightforward for selecting the alternative thermal gasification method that is the closest to the ideal thermal gasification technique and farthest from the negative ideal thermal gasification technique, it is sensitive to the available internal and external conditions for the gasification technology. Downdraft gasifiers exhibit the best performance in terms of a higher weight of 60% for environmental effects under the recycling scenario, with 0.1% and 0.0125% by volume of carbon dioxide and methane emissions, and under the non-recycling scenario, with 0.125% and 0.02% by volume of carbon dioxide and methane emissions. Downdraft gasifiers have a maximum close value for the ideal solution, with maximum values of 0.710 and 0.706 for the non-recycling and recycling municipal solid waste for entropy based on the non-recycling data set and 0.727 and 0.703 relative to the entropy weight based on the recycling data set. Circulating fluidized beds demonstrate the best ranking when a greater weight of 60% is chosen for the economic criterion. Dual-bed gasifiers rank well for non-recycling MSW, whereas updraft and dual-bed gasifiers rank equally for recycling MSW. The selection of the best gasification technique for MSW waste is sensitive to the environment and economic scenario based on the expert's preferences. As per the expert 1 criteria, which give maximum weight to the environment, downdraft gasifiers emerge as the best suitable alternative considering the preference for the environmental impact. Decision-makers should carefully consider the weighting scenarios and the importance assigned to different criteria based on the environmental, economic, technological, and fuel requirement performance aspects. Experimental analysis: Z.K., A.U.R., and A.S.; Methodology: Z.K., A.U.R., Y.S.U., and A.S.; Theoretical model: Z.K., A.U.R., and A.S.; Writing and Original draft: Z.K. and A.S.; and Review and editing: A.S. and H.S.A. All authors have read and agreed to the published version of the manuscript. This research was funded by the Deputyship for Research and Innovation, \"Ministry of Education\" in Saudi Arabia, grant number IFKSUDR_E155. Not applicable. The data presented in this study are available in this article. The authors extend their appreciation to the Deputyship for Research and Innovation, \"Ministry of Education\" in Saudi Arabia for funding this research through the project number IFKSUDR_E155. The authors declare no conflict of interest.