Geological context and thermo-economic study of an indirect heat ORC geothermal power plant for the northeast region of Algeria

Abstract

This article presents a study of the electricity generation potential using ORC systems of the most important geothermal sites in northeastern Algeria, combining geological, thermodynamic and economic analysis. The results highlight that geothermal electricity is technically feasible with the selected indirect heat ORC geothermal plant. Such production can present an interesting economic profitability when considering the international electricity price. The best economic performance was obtained for the geothermal site of Meskhoutine leading to a depreciated payback period of 10.8 years. The electricity production cost was evaluated at 0.21$/kWh for an electricity production capacity of 498 kW. Such performance is completely breakdown when considering Algerian subsidised electricity prices. These subsidies must be revised. Otherwise, it will harm the profitability of renewable energy systems, limit their development, and constrain seriously the Algerian energy transition road map. In addition, this study highlights that the selected indirect ORC configuration presents an important internal auxiliary consumption, especially for the Air Condenser (AC) unit, and was not suitable for geothermal temperatures below 117 °C. Other configurations, especially hybridisation and combined heating and power production are prioritized for future investigation.