CO2 emission assessment of the geothermal power station Los Humeros, Mexico. (September 2022)

• Record Type: Journal Article
• Authors: González-García, H.; Francke, H.; Göllner-Völker, L.; Welsch, B.; Kranz, S.; Huenges, E.; Schebeck, L.; Sass, I.
• Is Part Of: Geothermics. Volume 104(2022)
• Publication Date: 2022-09
• Subjects: CO2 footprint -- Global warming potential -- Geothermal power plant -- Life cycle assessment -- Los Humeros; Hydrogeology -- Periodicals; Geothermal resources -- Periodicals; Énergie géothermique -- Périodiques; GEOTHERMAL ENGINEERING; GEOTHERMAL ENERGY; GEOTHERMAL EXPLORATION; Geothermal resources; Hydrogeology; Periodicals; Electronic journals; 621.44
• DOI: 10.1016/j.geothermics.2022.102471
• Languages: English
• ISSNs: 0375-6505

Abstract

Highlights: Estimation of the CO2 eq per kWhel for a geothermal power station in Mexico. Creation of a detailed life cycle inventory. Identification of the CO2 eq hotspots within the generation process. Mitigation options to reduce the power station CO2 footprint. CO2 emissions due to exploitation is 10 times higher than the natural CO2 release in the area covered by the power station. Abstract: This work presents the estimation of the CO2 eq emissions of the geothermal power station in Los Humeros, Mexico. The calculation takes the emissions of the CO2 contained on the extracted geothermal brine plus the CO2 footprint by the power station construction. The carbon footprint estimation is based on technical reports generated by the owner company. It considers all the commissioning activities and also the operational phase of the power plant, which is assumed to span a lifetime of 30 years. The results indicate a total emission from 442 to 568 g C O 2 eq / kW h el . Of these emissions 9 to 12% are contributed indirectly by the power station construction whereas 88 to 91% are released directly during operations due to the natural content of CO2 in the steam. When comparing the results with the natural discharge of CO2 in the production area, the emissions of CO2 eq is 10 times faster. Solutions are proposed to reduce the footprint of CO2 eq per kWhel . In the short term the use of all the installed capacity in the field reduces the footprint by 25%. Another option is to use closed cycle technology with a binary power station instead of the single-flash power plants. This showed 82% reduction of CO2 eq emissions; accompanied by a reduction of electricity production by 16% due to the lower conversion efficiency. Graphical abstract: Image, graphical abstract