Green Supplier Selection with Fuzzy Multi-Objective Linear Programming and Interval Type-2 Fuzzy AHP Method

In recent years Green Supplier Selection (GSS) has been confronted increasingly attention by companies, researchers and customers in recent years due to legislations, increased customer awareness, non-governmental organizations, public and social responsibilities. Supplier selection is one of the most important factor playing a role in supply chain management. Improving the environmental performance of suppliers is a critical importance for development of green supply chains. Suppliers have a great importance for improving the performance of green supply chain management as they supply the raw materials required for production in any business. As a result, more and more organizations are investing in various green initiatives such as green purchasing, green packaging and reverse logistics to improve business performance and competitiveness. However, in supplier selection traditional criteria such as price, quality, delivery, etc. are taken into consideration and other criteria for measuring the green performance of suppliers are ignored. In order to achieve higher performance and competitiveness objectives, decision makers should apply the best method to solve the GSS problems and choose the most appropriate criteria. In general, the green supplier evaluation and selection problems are uncertain and the fuzzy set theory helps to convert decision makers preferences and opinions into meaningful results using linguistic variables for the evaluation of suppliers according to various criteria. Due to lack of information, limited quantitative information, companies’ specific contexts, and changing supplier histories, GSS evaluation and selection problems are a challenging process. In this study, an integrated method using interval type-2 Fuzzy Analytical Hierarchy Process (FAHP) method and Fuzzy Multi-Objective Linear Programming (FMODP) model is proposed for evaluating the performances of green suppliers. The interval type-2 FAHP method is more suitable than the type-1 fuzzy sets to reflect the uncertainty of decision makers opinions and in the first stage weights of the criteria are obtained by using the interval type-2 FAHP method for the GSS. In the second stage, a new FMODP model is proposed consists of objectives such as cost, late delivery CO2, emission, pollution production and usage of environmentally friendly material. Then weights obtained from the FAHP method are used in the FMODP model and the optimal solution is obtained for evaluation of suppliers. The applicability of the proposed method is demonstrated on an example.