Techno-Economic Evaluation of reversible Organic Rankine Cycles in geothermal combined Heat and Power PlantsTechno-Economic Evaluation of reversible Organic Rankine Cycles in geothermal combined Heat and Power Plants

Organic Rankine Cycles (ORCs) are widely used in geothermal combined heat and power (CHP) plants to generate electricity when the geothermal heat supply exceeds the demand of the attached district heating network (DHN). In recent years, the reversible use of ORCs as high-temperature heat pumps (HTHPs) has gained interest in both academia and industry. These enable flexible plant operation in either operation mode requiring only minor modification in the plant components. The use of a RHP in a geothermal CHP plant has a significant potential to reduce the need for fossil peak load boilers by providing the required heat using the HTHP. Between the DHN heat exchanger and the reinjection well, the geothermal brine is used as a heat source for the HTHP. Existing studies suggest the general potential of RHP applications, however a detailed thermo-economic evaluation is missing for a geothermal CHP application. This work evaluates the potential of RHPs to optimize the economic performance of a geothermal CHP plant by a detailed techno-economic plant analysis based on annual simulations of realistic heat demand profiles with an hourly resolution. Established cost estimation methods from literature and real energy cost data from recent years are used. With the heat and electricity pricing used in this work, employing a RHP increases the return on investment from 1.97% for a conventional plant layout to 2.09%. A sensitivity analysis with respect to gas and electricity purchase prices indicates economic benefits of RHP plant designs over conventional plants in future energy systems.     «

Organic Rankine Cycles (ORCs) are widely used in geothermal combined heat and power (CHP) plants to generate electricity when the geothermal heat supply exceeds the demand of the attached district heating network (DHN). In recent years, the reversible use of ORCs as high-temperature heat pumps (HTHPs) has gained interest in both academia and industry. These enable flexible plant operation in either operation mode requiring only minor modification in the plant components. The use of a RHP in a ge...     »