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CO2 Emission in Geothermal Systems and Resources

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "H2: Geothermal".

Deadline for manuscript submissions: closed (16 May 2022) | Viewed by 10999

Special Issue Editors


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Guest Editor
Earth Science Department, Pisa University, Pisa, Italy
Interests: Geothermics; Exploration of geothermal resources; Geothermal systems in volcanic areas; CO2 emissions in geothermal areas; Volcanology

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Guest Editor
Earth Science Department, Pisa University, Pisa, Italy
Interests: Volcanology; feeding systems of volcanoes; magma chambers; volatile components and magma explosivity; reconstructions of explosive eruptions; surface natural degassing in geothermal areas

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Guest Editor
RE&E, Rethinking Energy and Environment, 00184 Rome, Italy
Interests: Experienced manager with over 32 years of experience in senior commercial and technical roles in Exploration&Production and Renewable companies, including Eni, Enterprise Oil, OMV, Shell and Enel. Direct experience of working on North Africa, Middle East, S. Europe/Mediterranean Sea, North Sea/Norway, Russia, Balkans/Black Sea, South America.

Special Issue Information

Geothermal energy provides a valid contribution to the mitigation of climate change because greenhouse gases, in particular CO2, are not produced in the electricity and thermal energy generation cycles; geothermal energy is considered CO2-free in respect to fossil fuels. The natural degassing of CO2 from the Earth is a known and partially quantified phenomenon in volcanic and non-volcanic areas. Several papers evidence the occurrence of huge natural emission of CO2 in geothermal areas. The Special Issue is devoted to increasing our knowledge of the natural phenomenon of Earth degassing due to thermal and geodynamic processes occurring at depth in the Earth, further highlighting relations between natural gas emissions and emissions driven in power plants and their reciprocal influence in respect to the total budget of CO2 emissions in atmospheric in geothermal systems. This Special Issue is also open to contributions exploring geothermal areas through mapping of CO2 natural flux and as a tool for fault and fracture tracing.

Prof. Alessandro Sbrana
Dr. Paola Marianelli
Dr. Roberto Gambini
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Geothermal Energy
  • Natural CO2 emissions
  • CO2 natural soil flux

Published Papers (4 papers)

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Research

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22 pages, 11766 KiB  
Article
Thermodynamic Modeling of Mutual Solubilities in Gas-Laden Brines Systems Containing CO2, CH4, N2, O2, H2, H2O, NaCl, CaCl2, and KCl: Application to Degassing in Geothermal Processes
by Salaheddine Chabab, José Lara Cruz, Marie Poulain, Marion Ducousso, François Contamine, Jean Paul Serin and Pierre Cézac
Energies 2021, 14(17), 5239; https://0-doi-org.brum.beds.ac.uk/10.3390/en14175239 - 24 Aug 2021
Cited by 7 | Viewed by 2088
Abstract
With the growing interest in geothermal energy as a renewable and sustainable energy source, nowadays engineers and researchers are facing technological and environmental challenges during geothermal wells’ operation or energy recovery improvement by optimizing surface installations. One of the major problems encountered is [...] Read more.
With the growing interest in geothermal energy as a renewable and sustainable energy source, nowadays engineers and researchers are facing technological and environmental challenges during geothermal wells’ operation or energy recovery improvement by optimizing surface installations. One of the major problems encountered is the degassing of geothermal brines which are often loaded with dissolved gases, resulting in technical problems (scale formation, corrosion, reduced process efficiency, etc.) and environmental problems through the possible emission of greenhouse gases (CO2, CH4 and water vapor) into the atmosphere. In this work, a method to predict, from readily available information such as temperature and GLR, the bubble point pressure of geothermal fluids as well as the GHG emission rate depending on the surface conditions is presented. This method is based on an extended version of the Soreide and Whitson model with new parameters optimized on the solubility data of several gases (CO2, CH4, N2, O2 and H2) in brine (NaCl + CaCl2 + KCl). The developed approach has been successfully used for the prediction of water content of different gases and their solubilities in different types of brines over a wide temperature and pressure range, and has been applied for the prediction of bubble point pressure and GHG emissions by comparing the results with available industrial data of geothermal power plants including the Upper Rhine Graben sites. Full article
(This article belongs to the Special Issue CO2 Emission in Geothermal Systems and Resources)
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22 pages, 98094 KiB  
Article
Analysis of Natural and Power Plant CO2 Emissions in the Mount Amiata (Italy) Volcanic–Geothermal Area Reveals Sustainable Electricity Production at Zero Emissions
by Alessandro Sbrana, Alessandro Lenzi, Marco Paci, Roberto Gambini, Michele Sbrana, Valentina Ciani and Paola Marianelli
Energies 2021, 14(15), 4692; https://0-doi-org.brum.beds.ac.uk/10.3390/en14154692 - 02 Aug 2021
Cited by 4 | Viewed by 3376
Abstract
Geothermal energy is a key renewable energy for Italy, with an annual electric production of 6.18 TWh. The future of geothermal energy is concerned with clarity over the CO2 emissions from power plants and geological contexts where CO2 is produced naturally. [...] Read more.
Geothermal energy is a key renewable energy for Italy, with an annual electric production of 6.18 TWh. The future of geothermal energy is concerned with clarity over the CO2 emissions from power plants and geological contexts where CO2 is produced naturally. The Mt. Amiata volcanic–geothermal area (AVGA) is a formidable natural laboratory for investigating the relative roles of natural degassing of CO2 and CO2 emissions from geothermal power plants (GPPs). This research is based on measuring the soil gas flux in the AVGA and comparing the diffuse volcanic soil gas emissions with the emissions from geothermal fields in operation. The natural flux of soil gas is high, independently from the occurrence of GPPs in the area, and the budget for natural diffuse gas flux is high with respect to power plant gas emissions. Furthermore, the CO2 emitted from power plants seems to reduce the amount of natural emissions because of the gas flow operated by power plants. During the GPPs’ life cycle, CO2 emissions in the atmosphere are reduced further because of the reinjection of gas-free aqueous fluids in geothermal reservoirs. Therefore, the currently operating GPPs in the AVGA produce energy at a zero-emission level. Full article
(This article belongs to the Special Issue CO2 Emission in Geothermal Systems and Resources)
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16 pages, 4334 KiB  
Article
Tracing Ancient Carbon Dioxide Emission in the Larderello Area by Means of Historical Boric Acid Production Data
by Alessandro Lenzi, Marco Paci, Geoffrey Giudetti and Roberto Gambini
Energies 2021, 14(14), 4101; https://0-doi-org.brum.beds.ac.uk/10.3390/en14144101 - 07 Jul 2021
Cited by 4 | Viewed by 2638
Abstract
The impact of natural CO2 emissions in the development of geothermal areas is presently gaining more attention than ever before. In Italian geothermal fields, a reduction in the natural CO2 emissions has been observed. This paper reviews and provides an analysis [...] Read more.
The impact of natural CO2 emissions in the development of geothermal areas is presently gaining more attention than ever before. In Italian geothermal fields, a reduction in the natural CO2 emissions has been observed. This paper reviews and provides an analysis of the historical production data of boric acid from 1818 to 1867 used to calculate the natural emissions of CO2 associated with boric acid production that pre-dates the use of geothermal resources for power production, which started in 1913. Boric acid was already being extracted from the natural geothermal fluids in geysers and natural ponds emitting steam and gases. After 1827 the ‘lagone coperto’ (covered lake) equipment optimized production, and the drilling of shallow wells (20–30 m) starting in 1836, which further increased the quantity of its extraction. The first geothermal reservoir was developed at the turn of the century and the Larderello geothermal field began to grow. The use of deep wells, keeping pace with the power production, led to the gradual disappearance of the natural ponds and the ‘lagoni’ (lakes) in the historical area, so the residual natural emission of CO2 is presently restricted to diffuse soil emission. Comparisons of the ancient CO2 emissions with those of the Geothermal Power Plant (GPP) in the Larderello area show that both amounts are in the same order of magnitude, suggesting a balance between the depletion of natural emissions and geothermal activity. Full article
(This article belongs to the Special Issue CO2 Emission in Geothermal Systems and Resources)
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Review

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15 pages, 4908 KiB  
Review
The Carbon Dioxide Emission as Indicator of the Geothermal Heat Flow: Review of Local and Regional Applications with a Special Focus on Italy
by Giovanni Chiodini, Carlo Cardellini, Giulio Bini, Francesco Frondini, Stefano Caliro, Lisa Ricci and Barbara Lucidi
Energies 2021, 14(20), 6590; https://0-doi-org.brum.beds.ac.uk/10.3390/en14206590 - 13 Oct 2021
Cited by 7 | Viewed by 2013
Abstract
We review the methods based on the measurement of CO2 emissions for the computation of geothermal heat flow, both at a local (hydrothermal sites, a few km2) and regional scale (hundreds km2). At the local scale, we present [...] Read more.
We review the methods based on the measurement of CO2 emissions for the computation of geothermal heat flow, both at a local (hydrothermal sites, a few km2) and regional scale (hundreds km2). At the local scale, we present and discuss the cases of the Latera caldera and Torre Alfina (Italy) geothermal systems. At Torre Alfina and Latera, the convection process sustains a CO2 emission of ~1 kg s−1 and ~4 kg s−1, and heat flows of 46 MW and 130 MW, respectively. At the regional scale, we discuss the case of the central Apennine (Italy), where CO2 mass and enthalpy balances of regional aquifers highlights a wide and strong thermal anomaly in an area of low conductive heat flow. Notably, the CO2/heat ratios computed for the central Apennines are very similar to those of the nearby geothermal systems of Latium and Tuscany, suggesting a common source of CO2-rich fluids ascribed to the Tyrrhenian mantle. Full article
(This article belongs to the Special Issue CO2 Emission in Geothermal Systems and Resources)
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