Environmental benefits for a geothermal power plant with CO2 reinjection: case study of the Kizildere 3 U1 geothermal power plant

Abstract

Geothermal power plants (GPP) with high non condensable gases (NCG) content geothermal fluid have shown to be environmental impacting relating to their energy production, which could be critical if no corrective actions are achieved. The GPP of Kizildere 3 U1, located in Türkiye (Denizli), in where the geothermal fluid contains high percentage of CO2, 99% of the NCG fraction, which represents the 3% of the geothermal fluid mass, is taken as a relevant case study to implement a new innovation consisting of NCG reinjection to reduce the amount of NCGs released to the atmosphere. In order to calculate the present environmental impacts which the plant is causing (baseline); and the potential reduction of environmental impacts which can be achieved with the innovation (reinjection), a life cycle assessment (LCA) calculation were developed. Primary data were collected for all the relevant stages of the energy conversion cycle and complemented where necessary with secondary data from other geothermal power plants studies. The main results of the baseline environmental assessment show that the construction phase is the most impacting phase due to the materials used in the power plant building construction, electrical generation equipment and distributed machinery and infrastructures; the effects in the operation phase are dominated by the geothermal fluid composition. In this sense, the application of CO2 reinjection at the Turkish site into the reservoir will prevent the emission of 1,700 tons·year−1 in the pilot site and 10% of the total emissions released along the life span of the GPP.