چكيده به لاتين
In this research, a solar cell supply chain including a domestic supplier, an external supplier, and an assembler in the presence of the government is considered. The market demand is dependent on the price and efficiency of both the internal and external solar systems. In this research, the solar cell supply chain model is investigated under four situations. The model incorporating the government's interference includes three scenarios: (1) the presence of the domestic supplier in a monopolistic market; (2) the entry of an external competitor into a competitive market (3) government involvement in a competitive market under non-cooperative Nash behavior (decentralized). Besides, due to the importance of government and tariffs, the third scenario is also formulated and analyzed considering both the centralized and collaboration setting. At the end, the function of the government is considered as the main objective in order to calculate the optimal government tariffs. The government intervention model shows that the third scenario results in the lowest price and the highest efficiency thanks to the government interference. Improvement is observed in efficiency of implementing the second scenario, which is resulted from the competition between domestic and foreign suppliers. Profit and the values of decision variables under collaboration setting are close to the centralized one, both of which result in higher values compared to the decentralized conditions. In the model considering the policies of the supply side and the government's demand side in the solar cell supply chain, a new mathematical model is presented in which the supply side and demand side policies are presented taking into account the government and the competition between the suppliers. At first, both policies are formulated under the non-cooperative Nash game, and then the government function is optimized under these two policies to obtain government’s tariffs. In this model, the impact of the qualitative factors, economic, and tax is observed on the government revenue growth. A greater impact of the qualitative aspects in comparison with the economic factor is also observed in raising government’s profit. The positive impact of government’s tariffs on improving the price, efficiency, and profits of government and members is another significant result in this model. In the optimal scenarios for the solar cell supply chain, considering the degradation in the power plants, in the first stage, the three scenarios are modeled and formulated for two types of solar cells (dye-sensitized and Perovskite) under the non-cooperative Nash game. In the next step, the optimal solutions resulted from the three scenarios of Nash models are inputted in the solar cell's math mathematical model. The solar cell power model determines how many internal or external solar panels, dye-sensitized, or Perovskite, should be installed or replaced under which scenario and in which period. This model specifies the amount of energy generated in each scenario and each period, and the optimal scenario is finally determined. Scenario 3 shows better results in terms of installing and replacing solar panels at a power plant with respect to the price and efficiency. In the closed loop supply chain model considering the government interference and collection efforts, a new mathematical model is presented without the presence of the government and also considering the government intervention, and then, formulated under the follower-leader Stackelberg game. The model addresses a three-level solar cell supply chain which consists of a supplier, an assembler, and a third-party logistics in which the third-party logistics is a follower, and the supplier and assembler are the chain's leaders. This model expresses the impact of government tariffs on reducing technology costs and improving the efficiency of solar cells. It also identifies the effect of government intervention on reducing the cost of collection efforts, motivating the third-party logistics in collecting solar cells which have been used before. This model shows the effect of using the subsidy policy of the supply- side in improving the closed-loop supply chain for solar cells. Finally, the proposed models are solved using MATHEMATICA and GAMS software, the results of which investigated under several numerical examples. In addition, sensitivity analysis on key parameters is implemented to provide management insights to enhance the efficiency of the solar cell supply chain.
