In this presentation, the partial alteration of fuel consumption of conventional fossil-fueled power plants by biomass gasification will be described and considered by presenting the novel models. For this purpose, energy modeling of the advanced gasification systems to supply a share of the gas fuel will be fulfilled. The results of the advanced cycles will be shown by considering the reasonable capacities for the design and implementation. Primary fossil fuels such as natural gas, oil, and coal could be replaced with syngas produced by gasifiers. In addition, heat recovery of the plant’s stack using the high and low-temperature cycles has been improved in recent years, so that the total efficiency modification potentials will be discussed in this chapter. Therefore, the competitive advantage of the proposed cycles will be enhanced compared to conventional power generation systems. Furthermore, the parametric studies of the components affecting the integrated cycle performance, such as alternative biomass fuels, moisture content of biomass fuel, steam to biomass ratio, and equivalence ratio of the gasifier, have been performed, that each factor will be obtained. Eventually, by utilizing the proposed approaches, it will be possible to gradually substitute the consumed fossil fuels of power plants with renewable resources to achieve the targets of sustainable energy development.