Novel schemes to hybridize geothermal power plants with concentrated solar thermal and biomass.

Date

2024-6-27

Author

Çelebi, Bertuğ Serhan

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A novel three-way hybridization, having geothermal-CST-biomass, is studied in this research. Kızıldere-2 (KZD-2) triple flash and binary hybrid geothermal power plant (GPP) is used as a case study. Furthermore, its issues related to enthalpy decrease with years, causing excess capacities in turbines, declining performance during summer days, and lack of flexibility and dispatchability are addressed. A topping cycle of hybrid CST-biomass running on a steam Rankine cycle is designed. This topping cycle would generate its own power and also supply an additional steam flow to the bottoming KZD-2 GPP, using its excess turbine capacity. The model is built and simulated on the TRNSYS environment to study the effects of daily and seasonal resource variations. The biomass resource used is the local Olive Residue (OR), found more during winter harvest times. Moreover, for CST, parabolic trough collectors are used. The resulting study showed that the solar resources during summer times can help cover for the declining performance of KZD-2. Moreover, the biomass resource OR can add more power during winter when solar resources are lacking. The two combined can supply KZD-2 with an additional steam flow that brings its Intermediate Pressure Turbine (IPT) back to total capacity. Lastly, biomass can be used as a readily available energy resource with variable combustion rates to account for hourly fluctuations. This way, the flexibility and dispatchability of the plant are increased. The results showed that in sunny and clear sky conditions, more than 20 MWe of additional power can be obtained. The resulting biomass fuel consumption rate changes between 4.2 - 5.8 kg/s, depending on the season and solar resources available. Lastly, a techno-economic analysis is performed, resulting in an LCOE of 81.19 $/MWh, and a payback period of 5 years with YEKDEM purchasing agreement and 9 years with spot market prices. which are competitive values among renewable energy technologies.

Subject Keywords

hybridization, geothermal, Concentrated Solar Thermal (CST), biomass

URI

https://hdl.handle.net/11511/110390

Collections

Graduate School of Natural and Applied Sciences, Thesis