## 1 Introduction  
Wind power is the use of air flow through wind turbines to provide the mechanical power to turn electric generators. Wind power, as an alternative to burning fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, consumes no water, and uses little land [1].  
Nowadays, at least 90 other countries are using wind power to supply their electric power grids [2]. Annual wind power capacity additions in 2018 is 539.581 MW [3]. Yearly wind energy production is also growing rapidly and has reached around 10.8% of worldwide electric power usage [4].  
Existing coal and gas fields in the near future will be exhausted, so many countries are now focused on developing wind resources. Wind energy is the latest and most powerful source of energy in the world today. The development of wind energy in Vietnam toward the objective of mitigating the impacts of climate change is among the solutions that are considered feasible today. Currently, the first 100 MW wind farm has been operating and is conducting research into phases up to 2025, for up to 1000 MW.  
In this work, the author considered seven Decision Making Units (DMUs) including Quang Ninh, Binh Thuan, Quang Tri, Ninh Thuan, Ninh Thuan, Tra Vinh and Hai Van for building wind power plants in Vietnam. This is because these provinces have the greatest potential for harnessing wind energy. Wind power could reach 800 MW. In addition to high average speed, local wind tends to be steady due to the small number of storms. During the monsoon period, winds reach speeds of six to seven meters per second. Wind power plant site selection is identified as a critical issue that could affect economic, environmental, technological, and social factors. Further, location selection is complicated, in that decision-makers must have broad perspectives concerning qualitative and quantitative criteria. Furthermore, there is no work that applies these models for wind power plant location selection in Vietnam Thus, the authors propose a Multi-Criteria Decision Making (MCDM) model, including Fuzzy Analytic Hierarchy Process (FAHP) and The Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), to select the optimal location for construction of wind power plants in Vietnam. FAHP is proposed for defining the weight of each potential location in the first stages of this work. The FAHP embeds the fuzzy theory to basic analytic hierarchy process (AHP), which was developed by [PERSON] [5]. FAHP is a widely used decision-making technique in many MCDM problems. In a general AHP model, the objective is in the first level, and the criteria and subcriteria are in the second and third levels, respectively. Finally, the options are found in the fourth level. A general MCDM process model is shown in Figure 1.  
The FAHP can be used for ranking alternatives, but the disadvantage of the FAHP model is that input data, expressed in linguistic terms, depends on the experience of experts. Thus, the authors proposed TOPSIS models for ranking potential locations in the final stages. TOPSIS is a multi-criteria decision analysis method. TOPSIS is based on the concept that the chosen alternative should have the  
Figure 1: General Multi-Criteria Decision Making (MCDM) process [6; 7].  
shortest geometric distance from the positive ideal solution (PIS) and the longest geometric distance from the negative ideal solution (NIS).  
The remainder of the article provides background materials to assist in developing the MCDM model. Then, hybrid FAHP-TOPSIS approaches are presented to select the best location for wind power plant construction from seven potential locations in Vietnam. The results and contributions will be discussed at the end of this paper.