## 2 Materials and Methods  
This paper follows the following structure:  
* Problem definition is given.
- Previous literature research is shared.
* The boundaries of the research due to the YEKDEM incentive are shared.
- Integration of CST and biomass as a topping cycle is explained.
- The detailed schematic of the hybrid plant is given.
- The details of the share of steam generation between CST and biomass are shared.
- The hybrid plant simulation model made in TRNSYS is explained.
* The important parameters are given.
- The energetic performances are shared.
- The economic results are shared.
* The results are discussed, and the shortcomings are shared.
* Conclusions  
Figure 1: The graphical summary of the literature review and how each item influenced this paper.  
The main points from the paper are summarized.  
In 2005, Turkiye established YEKDEM as an incentive for domestic RE power plants [19]. YEKDEM is a power purchasing agreement that guarantees the purchase of power in US Dollars. This incentive is valid for all plants built before or in 2020 and lasts for ten years. Although the KZD-2 plant has completed its ten years under this incentive, this study also considers utilizing YEKDEM to obtain both perspectives of a power purchasing incentive and spot market prices. Plants benefiting from YEKDEM are allowed to add hybridizations with other RE sources up to 20% of the original power plant. Consequently, this study sizes the topping cycle to generate an additional 16 MW\({}_{\text{e}}\) (i.e., 20% addition 80 MW rated capacity). Moreover, by generating additional steam flow using the topping cycle, the excess turbine capacity of the IPT of KZD-2 will be utilized. Figure 2 shows the energy flow of the hybrid plant and the proposed integration. The red and blue colors represent the high and low operating temperatures for the topping and bottoming cycles, respectively.  
Figure 3 shows the detailed schematic of the hybrid plant. All elements above the dashed box are additional components added by this hybridization, with the exception of the WCT, which belongs to the KZD-2. The topping cycle powered by CST and biomass is shown in Figure 3, and the share of steam generation in the topping cycle is illustrated. The topping cycle pump adjusts the water flow rate to the CST or biomass parts. The condenser serves as the connection between the topping and bottoming cycles. The figure also shows that the exit of IPT feeds the LPT.  
Figure 2: Energy flow diagram of the hybrid plant.  
Figure 3: Hybrid plant schematic.  
The share of steam generation between CST and biomass is determined as follows. The CST field and biomass boiler are sized to generate sufficient steam to generate 10 MW\({}_{\text{e}}\) and 6 MW\({}_{\text{e}}\) power, respectively. However, to compensate for the variable solar resources, the biomass boiler is oversized by adding an additional 4 MW\({}_{\text{e}}\). Specifically, OR is more abundant in the winter, and this additional 4 MW\({}_{\text{e}}\) will be utilized entirely in winter, but only 2 MW\({}_{\text{e}}\) will be used in summer. Lastly, during the night, the biomass will continue to operate to produce 10 MW\({}_{\text{e}}\) in winter and to produce 8 MW\({}_{\text{e}}\) in summer. This flexibility of biomass helps to strengthen its synergistic hybridization with CST.