The behavior of the solid waste gasification system, methanol production technology, and internal combustion engine fueled by syngas has been investigated. The purpose of this study is to investigate the probability distribution of data related to waste, syngas, methanol production, and power generation using the Monte Carlo method. In fact, in this paper, the purpose of this study is to obtain the probability distribution of synthesis gas from gasification technology, the probability distribution of methanol production from methanol production from synthesis gas, and the probability distribution of power generation from internal combustion engine technology. Also, this study presents a method for estimating the capacity factor of a waste-to-energy power plant. Monte Carlo simulation was performed using MATLAB R2019a. The results showed that the system has a syngas flow rate of 33.53 Nm3/h, a methanol production amount of 16.49 kW, a production power of 10.35 kW, and a power factor of 0.985.By examining the research related to waste gasification and power generation with an engine, it is observed that all of them have considered a constant analysis for waste, while in reality, the analysis of waste in waste gasification plants is variable and has a statistical form. After obtaining the probability distribution of outputs, two scenarios of electricity sales and methanol sales from synthesis gas were examined economically. The results show that the scenario of electricity production from synthesis gas is more economical overall. Also, the economic factors are suitable for the methanol production scenario and both scenarios are economically justifiable.