The introduction of automated material handling systems such as automated guided vehicles (AGVs) and autonomous mobile robots (AMRs) is becoming increasingly widespread in the manufacturing industry due to their potential to improve operational efficiency and reduce labor costs. While these systems automate tasks previously performed by humans, discussions regarding the scope of their implementation have often focused on the idea that simple transportation tasks can be automated by simply introducing automated equipment. However, while automating transportation may seem as straightforward as creating a conveyor line to connect multiple locations, it actually involves significant initial costs, energy consumption, and operational expenses such as maintenance. Additionally, environmental taxes being introduced by various countries to achieve carbon neutrality by 2050 and the costs of batteries for automated transport systems must not be overlooked. The objective of this study is to investigate the environmental and economic impacts of deploying automated transport systems in factories, focusing on electricity consumption, associated carbon dioxide emissions, carbon taxes, and battery costs for automated transport vehicles. Using a simulation model, this study evaluates the investment payback at the time of implementation, considering the environmental tax impact of carbon dioxide emissions from automated systems, power consumption accounting for degradation, and battery replacement costs, using Thailand, Japan, Germany, and the United States as examples. The findings reveal that emerging countries not only face challenges in achieving investment payback due to low labor costs but also, as they rely on fossil fuels, will face increasing carbon taxes as the 2050 carbon neutrality target approaches, further eroding investment payback over time.