Technical and economical analysis of a solar–geothermal hybrid plant based on an Organic Rankine Cycle

Abstract A combined concentrating solar power system and a geothermal binary plant based on an Organic Rankine Cycle (ORC) is analyzed. Given a supercritical ORC, designed for the optimal utilization of an intermediate enthalpy geothermal source, a solar parabolic trough field was included in the plant, introducing an additional high temperature heat source for the cycle and increasing power production. The off-design performance analysis of the power cycle was performed first. An hour-by-hour simulation was then carried out to estimate the yearly production using a detailed solar field model. Finally, a differential economic analysis was performed to determine the cost of the additional electricity generated with the solar source. On the basis of the current cost of solar collectors, levelized costs of electricity of 145–280 €/MWh were obtained depending on the location of the plant: a competitive value with respect to large, stand-alone concentrating solar power plants.

[1]  M. McLinden,et al.  NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP, Version 8.0 , 2007 .

[2]  Ennio Macchi,et al.  Design Limits, Basic Parameter Selection and Optimization Methods in Turbomachinery Design , 1985 .

[3]  Y. Jaluria,et al.  An Introduction to Heat Transfer , 1950 .

[4]  Ronald DiPippo,et al.  Second Law assessment of binary plants generating power from low-temperature geothermal fluids , 2004 .

[5]  Ruggero Bertani,et al.  Geothermal power generation in the world 2005–2010 update report , 2012 .

[6]  K R Williams,et al.  Power from the sun , 1979 .

[7]  S. L. Dixon,et al.  Fluid mechanics, thermodynamics of turbomachinery , 1966 .

[8]  Susan Eitelman,et al.  Matlab Version 6.5 Release 13. The MathWorks, Inc., 3 Apple Hill Dr., Natick, MA 01760-2098; 508/647-7000, Fax 508/647-7001, www.mathworks.com , 2003 .

[9]  A. Lentz,et al.  Parabolic troughs to increase the geothermal wells flow enthalpy , 2006 .

[10]  Eckhard Lüpfert,et al.  Advances in Parabolic Trough Solar Power Technology , 2002 .

[11]  A. Lentz,et al.  Solar–geothermal hybrid system , 2006 .

[12]  R. Forristall,et al.  Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver , 2003 .

[13]  Ennio Macchi,et al.  Efficiency Prediction for Axial-Flow Turbines Operating with Nonconventional Fluids , 1981 .

[14]  Gregory J. Kolb,et al.  Final Report on the Operation and Maintenance Improvement Program for Concentrating Solar Power Plants , 1999 .