Zürich, Switzerland
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Muraoka H.,Japan National Institute of Advanced Industrial Science and Technology | Gunnlaugsson E.,Reykjavik Energy | Song Y.,Korea Institute of Geoscience and Mineral Resources | Lund J.,Oregon Institute of Technology | And 2 more authors.
Current Applied Physics | Year: 2010

Under a framework of the Geothermal Implementing Agreement (GIA) of the International Energy Agency (IEA), chemistry of thermal water is compared among Iceland, Japan, South Korea and the USA. The pH value of thermal water in Iceland shows 9 or 10, that is evidently higher than those of other silicic crust countries. It is ascribed to the host rock controls that hydrothermal water only attacks anorthite in basalt. The boron and chloride components of thermal water in Iceland are significantly lower than those in Japan and the USA. Their variation ranges show that the boron component in Iceland is 1 magnitude lower than other two countries and the chloride component is 0.5 magnitudes lower. It is also explained by the host rock controls that the basaltic crust in Iceland is 1 magnitude lower in boron and 0.5 magnitudes lower in chloride than the silicic crust in Japan and the USA. © 2009 Elsevier B.V.

Ollinger D.,GEOWATT AG | Baujard C.,GEOWATT AG | Kohl T.,GEOWATT AG | Moeck I.,German Research Center for Geosciences
Geothermics | Year: 2010

The main objective of the study was to develop and calibrate the thermal model of the Groß Schönebeck test site in Northeastern Germany, and to perform sensitivity analyses based on the availability of high-quality temperature data from deep wells. A 3D geological model of the area was constructed and then discretized into a finite element mesh that included 13 different lithologic units of variable thickness. Forward numerical calculations of the temperature field were performed based on measured and assumed data and properties. Finally, inverse modeling was used to improve parameter estimation and to obtain comprehensive statistic information. The results of the computations indicate some spatial thermal conductivity inhomogeneities in the different geologic layers and imply that the basal heat flux in the area is about 60 mW m-2. © 2009 Elsevier Ltd. All rights reserved.

Agency: Cordis | Branch: FP7 | Program: CP | Phase: ENERGY.2009.2.4.1 | Award Amount: 7.12M | Year: 2010

The project contributes to the improvement of the concept of Enhanced Geothermal Systems by investigating the role of induced seismicity, which is twofold: (i) an instrument to image fluid pathways induced by hydraulic stimulation treatments, which has been done to some extent in previous projects; and (ii) an implication of such treatments to potential seismic hazards. The mitigation of induced seismicity to an acceptable level is the major intent of this project. For this purpose, we set as our goals (1) to understand why seismicity is induced in some cases but not in others; (2) to determine the potential hazards depending on geological setting and geographical location; (3) to work out licensing and monitoring guidelines for local authorities, which should include a definition of what level of ground motion is acceptable; and (4) to develop strategies to fulfil the task of the stimulation and improve the hydraulic properties of the geothermal reservoir without producing large magnitude events. To accomplish the project goals a high quality database of case studies will be assembled. This will include data on seismicity and ground motion, geomechanics, reservoir characteristics, injection/production, and surface deformation, as well as information on the local stress field and local geology. The interpretation will be based on data from the sites: Soultz-sous-forts (France), Basel (Switzerland), Gro Schnebeck (Germany), KTB (Germany), Larderello/Latera (Italy), Campi Flegrei (Italy), Hengill, Krafla, Reykjanes (Iceland), Groningen (Netherlands), and others (Berlin, El Salvador; The Geysers, USA). The GEISER-project will overcome shortcomings of previous work by including model based forecast of stimulation and/or production induced seismicity. Developing soft stimulation strategies and guidelines on how to react on induced seismicity will support the acceptance of geothermal applications.

Baujard C.,GEOWATT AG | Schoenball M.,Karlsruhe Institute of Technology | Kohl T.,Karlsruhe Institute of Technology | Dorbath L.,EOST
Geothermics | Year: 2014

The occurrence of induced seismicity during reservoir stimulation requires robust real-time monitoring and forecasting methods for risk mitigation. We propose to derive an estimation of Mmax (here defined as the largest single seismic event occurring during or after reservoir stimulation) using hydraulic energy as a proxy to forecast the total induced seismic moment and to model the transient evolution of the seismic moment distribution (based on the Gutenberg-Richter relation). The study is applied to the vast dataset assembled at the European pilot research project at Soultz-sous-Forêts (Alsace, France), where four major hydraulic stimulations were conducted at 5km depth. Although the model could reproduce the transient evolution trend of Mmax for every dataset, detailed results show different agreement with the observations from well to well. This might reveal the importance of mechanical and geological conditions that may show strong local variations in the same EGS. © 2014 Elsevier Ltd.

Bayer P.,ETH Zurich | Saner D.,ETH Zurich | Bolay S.,ETH Zurich | Rybach L.,GEOWATT AG | Blum P.,Karlsruhe Institute of Technology
Renewable and Sustainable Energy Reviews | Year: 2012

An overview is presented on the last decade of geothermal heating by ground source heat pumps (GSHPs) in Europe. Significant growth rates can be observed and today's total number of GSHP systems is above 1 million, with an estimate of about 1.25 million mainly used for residential space heating in 2011. These systems are counted among renewable energy technologies, though heat pump operation typically consumes electricity and thus only a fraction of the energy produced is actually greenhouse gas (GHG) emission free. Consequently, only in the most mature markets of the Scandinavian countries and in Switzerland, calculated emission savings reach more than 1% compared to standard heatings. However, Sweden shows that more than 35% is possible, with about one third of these systems in Europe concentrated in this country. Our calculations demonstrate the crucial role of country-specific heating practices, substituted heat mix and primary electricity mix for country-specific emission savings. For the nineteen European countries studied in 2008, 3.7 Mio t CO 2 (eq.) are saved in comparison to conventional practice, which means about 0.74% on average. This reveals that many countries are at an early stage with great potential for the future, but even if the markets would be fully saturated, this average would barely climb to about 30%. These numbers, however, take the current conditions as reference, and when extrapolated to the future can be expected to improve by greener electricity production and increased heat pump performance. © 2011 Elsevier Ltd. All rights reserved.

Poppei J.,AF Consult Switzerland | Altenburger A.,Lucerne University of Applied Sciences | Mettauer P.,Mettauer AG | Papritz K.,Dr. Bernasconi AG Beratende Geologen und Hydrogeologen | Signorelli S.,Geowatt AG
Grundwasser | Year: 2016

The utilization of groundwater for heating and cooling is the second most common application of shallow geothermal energy. In contrast to closed-loop ground-coupled heat exchangers, changes in groundwater temperature and pumping in open-loop systems can have far-reaching impacts, often exceeding property limits. The limited resources on one hand, and the justified protection of groundwater on the other hand, result in a need for standardisation of this energy source. The Swiss Society of Engineers and Architects (SIA) released the standard 384/6 “Ground-coupled heat exchanger” in 2010, which was followed in April 2015 by standard 384/7 “Thermal utilization of groundwater”. The authors—associates and head of the commission—give an overview on how to deal with the specific needs, resulting from the interdisciplinary subject area, and from differences in demands and claims of the involved parties. We show how the challenges in quality assurance, functionality and environmental aspects are being met with a consensus of planners, managers and authorities during the implementation of the new standard. © 2015, Springer-Verlag Berlin Heidelberg.

Calcagno P.,Bureau de Recherches Géologiques et Minières | Baujard C.,GEOWATT AG | Guillou-Frottier L.,Bureau de Recherches Géologiques et Minières | Dagallier A.,Bureau de Recherches Géologiques et Minières | Genter A.,GEIE EMC
Geothermics | Year: 2014

The geothermal potential of a deep sedimentary-rock reservoir, in a Tertiary graben, the Limagne d'Allier basin (Massif Central, France), is assessed. The most interesting geothermal target is identified as a thick basal Tertiary sandstone overlying crystalline Paleozoic basement. The total amount of recoverable energy in this clastic aquifer is estimated at over 500PJ (500×1015J) in the modelled area. The most promising zones appear along the north-western edges of the basin, where sediment infill is thickest. The methodology used for estimating geothermal potential starts from geological field data. The first step is to obtain a better understanding of the structure and geometry of the target zone, using various data such as field measurements, and borehole and geophysical data. These data are reinterpreted through the construction of a 3D geological model. Inconsistencies are checked and turned into a coherent 3D interpretation. The second step consists in meshing the geological model into an unstructured 3D finite-element mesh where realistic thermal boundary conditions are applied. The temperature field is computed in a third step. The thermal calculation is achieved by assuming a purely conductive behaviour and through comparison with existing borehole profiles. The computed temperatures fit the measurements in the deepest part of the Limagne d'Allier basin, while the potential role of fluid flow is highlighted in its upper part, either within more permeable formations, or around the boreholes. A fourth, final, step maps the geothermal potential (recoverable energy) in the deepest part of the Tertiary graben, where the total amount of geothermal energy available is calculated. The result of this work provides valuable guidelines for geothermal exploration in the area and our methodology can be replicated elsewhere. © 2014 Elsevier Ltd.

Beardsmore G.R.,Hot Dry Rocks PL | Rybach L.,Geowatt AG | Blackwell D.,Southern Methodist University | Baron C.,Google
Transactions - Geothermal Resources Council | Year: 2010

This paper establishes a Protocol to estimate and map the Theoretical and Technical potential for Engineered (or Enhanced) Geothermal Systems (EGS) in a globally self-consistent manner compatible with current geothermal public Reporting Codes. The Protocol, derived and modified from that designed by the team lead by Professor David Blackwell at Southern Methodist University (Dallas, Texas), is divided into five stages: • Model the temperature, heat flow and available heat of the Earth's crust down to a depth of 10,000 m • Estimate the Theoretical Potential for EGS power in the crust down to a depth of 10,000 m • Estimate the Technical Potential that can be realized with current technology, and considering geographic, ecologic, legal and regulatory restrictions • Define a level of confidence in the estimated Technical Potential at each location, consistent with public Reporting Codes • Present results using common visualization and data architecture The goal of the Protocol is the production of regional estimates and maps of EGS potential that are directly comparable to one another globally. The maps, estimates and source data will be made freely available for public use and presented in common data formats such as the Keyhole Markup Language (KML) for Google Earth.

Badoux V.,Geowatt AG | Ollinger D.,Geowatt AG | Megel T.,Geowatt AG
International Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage | Year: 2013

The hydro-mechanical code HEX-S has been developed in the framework of geothermal projects to predict the risk of induced seismicity and to evaluate the development of the reservoir productivity while stimulating the reservoir. The investigations carried on so far considered geothermal reservoirs exploited by vertical to sub-vertical boreholes. In this paper, HEX-S is applied in a generic case study where the geothermal doublet is composed of two horizontal boreholes. The HEX-S simulator is then used to assess the performance of the reservoir configuration (hydraulic and thermic) and to evaluate the risk of induced seismicity.

Rybach L.,Geowatt AG
Transactions - Geothermal Resources Council | Year: 2010

Tunnels drain the rock zones located above them; as a result a considerable amount of warm water flows into the tunnels and subsequently to the portals. On accounts of its temperature this water cannot be released into nearby rivers without previously being cooled down, due to environmental regulation This energy reserve (drained hot water and heated air) can, however, be used at the tunnel portals for various applications. From Switzerland a whole suite of uses can be reported: space heating, greenhouses, balneology and wellness, fish farming (incl. caviar production).

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