Investigations carried out by various researchers on Solar Chimney Power Plant (SCPP) have proven its potential capability to generate large quantities of electrical energy, and now it seems this area of research has entered a new phase of the Hybrid SCPP. By combining the SCPP with other systems, researchers intend to eliminate its weaknesses and provide supplementary strengths for the conventional SCPP. In this paper, authors attempt to model a combination of SCPP and flare gas combustion products numerically, first to find a better application to diminish the tremendous amount of energy lost in gas flaring processes, second to improve the performance of SCPP Therefore, a three-dimensional model of the SCPP in Manzanares, Spain, was developed. Once grid independence evaluation and model validation had been completed, the combustion products of the flare gas were injected into the SCPP. Finally, the effects of hot gas injection on output power enhancement, the geometric optimization of the SCPP, and the contributions of solar radiation and hot gas to power generation were analyzed.The outcomes of this research determined that this combination can efficiently improve the power generation of the hybrid solar chimney power plant from 50 kW to 788 kW, shortening the chimney height of the plant by half, while not only does it avoid declining power generation, but also enhances it by four times, from 50 kW to 215 kW. Furthermore, it was found that the optimal gas injection location was under the collector near the inlet.