GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.1 GNGTS 2024 The European project SUCCEED for coupling Geothermal Energy and CCUS: innovatve monitoring technologies by actve-source seismic data acquisiton C. Bellezza, E. Barison, F. Poleto, A. Schleifer, F. Meneghini, G. Böhm, B. Farina OGS - Natonal Insttute of Oceanography and Applied Geophysics, Italy Geothermal energy is a natural and renewable energy source, but geothermal power producton generates greenhouse gas (GHG) emissions, in partcular CO 2 . Some studies estmated that the GHG emission from geothermal power plant can be higher than 1000 g/kWh (Fridriksson et al., 2017). In the view of reducing CO 2 emissions from geothermal power plants, for climate change mitgaton (carbon capture utlizaton and storage - CCUS) purposes, the Synergetc Utlisaton of CO 2 Storage Coupled with Geothermal Energy Deployment (SUCCEED) ACT project (2019-2023) aims to prove the feasibility of re-injectng the emited CO 2 into the same geothermal system to improve its performance and in the meanwhile to permanently storage the CO 2 by mineralizaton. The project investgated two diferent existng geothermal power plants, one is the Kizildere geothermal feld, located in the East of Büyük Menderes graben in Western Anatolia, Turkey, the other is the Hellisheiði geothermal feld, in Iceland. Here we present the work done for the geophysical monitoring and the results achieved at the Hellisheiði geothermal feld. In the framework of the project, our research focused on the development of innovatve reservoir- monitoring technologies at the Hellisheiði geothermal feld, an actve geothermal power plant located in the southern part of the Hengill volcanic system in the southwestern Iceland, close to the city of Reykjavik. The Hengill volcanic system is consttuted by a central volcano and a fssure swarm with a graben structure that extends to the northeast and southwest and it is located at the juncton of Reykjanes Volcanic Belt (RVB), the Western Volcanic Zone (WVZ) and the South Iceland Seismic Zone (SISZ) (Jóhannesson and Sæmundsson, 1998). The Hellisheiði geothermal feld has a temperature higher than 300°C at a depth of 1000 m below sea level and the steam combined heat and power plant is one of the biggest in the world with an installed producton capacity of 303 MWe and 210 MWh of energy. The CO 2 is added to the re- injected geothermal fuid as dissolved gas. The monitoring experiment consisted in a baseline survey and a tme lapse survey afer a long-lastng, contnuatve (a few months) injecton of CO 2 . The monitoring is performed by actve-source seismic data acquisiton using a novel electric seismic vibrator source (E-Vibe) and permanently installed Helically Wound Cable (HWC) fbre- optc distributed acoustc sensors (DAS) in shallow trenches. We present the resultng tme-stacked secton from the baseline HWC DAS acquisiton (July 2021) to investgate the complex basaltc system prior the CO 2 injecton. At the same tme, two co-linear acquisitons have been done with two- and three-components geophones to validate the results from the baseline HWC DAS system. The results showed a good consistency in the refected events and helped to defne the reservoir where we expect the injected CO 2 to be stored (Bellezza et al., 2023, under revision). We also show