Ladislaus Rybach

Ladislaus Rybach
ETH Zurich | ETH Zürich · Institute of Geophysics

Professor emeritus, Dr. Dr.h.c.

About

251
Publications
125,835
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7,225
Citations
Additional affiliations
August 1973 - present
ETH Zurich
Position
  • Professor Emeritus

Publications

Publications (251)
Article
Full-text available
Geothermal heat pump systems (GHP), producing from shallow resources, are the spearhead of geothermal achievement and development. Global heat delivery grew exponentially to 600 PJ in 2020. GHP is the fastest growing segment in geothermal technology and one of the fastest growing application of renewable energy technologies worldwide. Other, variou...
Article
Full-text available
Tunnel geothermal systems hold the potential to promote decarbonization of the building heating and cooling sector. They can be integrated into existing infrastructure, resulting in low additional costs. In addition, these systems have large contact areas with the ground leading to larger heat fluxes. However, tunnel geothermics is relatively unkno...
Article
Full-text available
Heat mining” is, in fact a complete deceptive misnomer. When a mineral deposit (e.g. copper) is mined and the ore has been taken out, it will be gone forever. Not so with geothermal resources: The heat and the fluid are coming back! Namely, the heat and fluid extraction create heat sinks and hydraulic minima; around these, strong temperature and pr...
Technical Report
Full-text available
The flights of the civil part ARM20c of the exercise were performed between June 12 th and June 19 th , 2020. According to the alternating schedule of the annual ARM exercises, the environs of the nuclear power plants Beznau (KKB) and Leibstadt (KKL) and the nuclear facilities of the Paul Scherrer Institute (PSI) and the Zwischenlager Würenlingen A...
Chapter
The Article describes the characteristics, design, and use of Geothermal heat pump systems, and consists of 12 Chapters: Introduction—The resource—Geothermal heat pumps (GHP) (Common types of ground coupling components, Further types: Energy piles, geothermal baskets, The core piece: The heat pump)—Heating and cooling with GHPs—Site investigations...
Technical Report
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Results of the airborne gamma spectrometry measurements within the framework of the 2019 Swiss exercise ARM19.
Article
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Sedimentary basins usually have significant geothermal potential. Deep aquifers are key components. The factors, conditions, and processes that define and control the potential are: processes during basin formation like sedimentation, karstification, fracturing; rock porosity, permeability/fluid content; depth/temperature; hydrogeology; production...
Technical Report
Full-text available
The measurement flights of the exercise ARM18 were performed between May 28th and June 1st, 2018. The exercise was organized by the National Emergency Operations Centre (NEOC) under coordination from the Expert Group for Aeroradiometrics (FAR). Representatives of KompZen ABC-Kamir participated both in the exercise and performed separate measuring f...
Technical Report
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Description of airborne Gamma spectrometry Systems of participating Teams, Results of the measurements, Comparison of the results of the different Teams and comparison with ground measurements, suggestions for a version 2.0 of ERS data Format.
Technical Report
Full-text available
The measurement flights of the exercise ARM16 were performed between June 27 th and July 1 st , 2016. The exercise was organized by the National Emergency Operations Centre (NEOC) under coordination from the Expert Group for Aeroradiometrics (FAR). Representatives of KompZen ABC-Kamir participated with a second Super Puma helicopter carrying the pr...
Chapter
Full-text available
Thanks to the regular reporting at World Geothermal Congresses, there is a reliable statistical base to assess the status and development trends in European countries. The assessment reveals that the geothermal heat pump (GHP) technology is present and growing in application. The top five countries engaged in developing this technology are Sweden,...
Article
Borehole temperature logs in urban areas often show deviation from the regional geothermal gradient that increases towards the land surface in the top ∼100 m. This deviation is the sum of two effects: atmospheric global warming and urban heating. To invert the temperature profiles (T-logs), a novel analytical model is presented to distinguish effec...
Article
Full-text available
When considering and reporting resources, the term "geothermal potential" is often used without clearly stating what kind of potential is meant. For renewable energy resources it is nowadays common to use different potentials: theoretical, technical, economic, sustainable, developable – decreasing successively in size. In such a sequence, the poten...
Article
Full-text available
The heat content of shallow or deep aquifers can be used for space heating. Two innovative systems are described below in detail: A geothermal heat pump system based on a single well in China (= shallow), and a cascading use of tunnel waters (= deep) in Switzerland. The "Single Well System" (HYY SWS) was invented and developed by Beijing Ever Sourc...
Article
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Based on global statistical data the current status of deep geothermal resource utilization for electricity generation is presented. Particular attention is paid to growth rates. The rates are compared with those of other renewable energies (biomass, hydro, solar photovoltaic (PV), wind). Whereas wind and solar PV exhibit annual growth rates of 25%...
Article
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A comprehensive overview of potential environmental effects during the life cycle of geothermal power plants is presented using widely scattered available information from diverse literature sources. It is shown that so far only few studies provide quantitative estimates on both direct and indirect environmental consequences. Life cycle assessment...
Article
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The a-priori knowledge of in-situ rock temperatures is of paramount importance in deep tunnels, e.g. for the design of ventilation and cooling during construction and operation. New 3D numerical model simulation was applied for rock temperature prognosis, with increasing degree of complexity (e.g. thermal and hydraulic ground properties, topography...
Chapter
Full-text available
A geothermal heat pump (GHP) is a central heating and/or cooling system that pumps heat to or from the ground. It uses the earth as a heat source (in the winter) or a heat sink (in the summer). They can be established in sizes from a few thermal kW to several MW capacity. GHPs are among the fastest growing renewable energy technologies: from 1995 t...
Article
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Das Buch beschreibt die vielfältigen Nutzungsmöglichkeiten geothermischer Energieressourcen. Bis zum Bau und Betrieb von Geothermie-Anlagen führt ein langer Weg. Es braucht dabei viele Weggefährten: Spezialisten aus zahlreichen Disziplinen. Strukturgeologen und Hydrogeologen, Geophysiker und Geochemiker, Bohr- und Reservoir-Ingenieure, Anlageplaner...
Article
Full-text available
Annually since 1989, biannually since 1994 the sites of the Swiss nuclear facilities (4 power plant sites, a nuclear research institute and a waste storage facility) are surveyed flying the same survey lines by airborne gamma ray spectrometry. The equipment and the data processing software used for those surveys was built and developed at the Insti...
Method
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This paper presents a revised version of the Global Protocol for Estimating and Mapping EGS Potential, first published in 2010
Technical Report
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This paper presents a revised version of 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 was first published in the Proceedings of the Geothermal Resources Council...
Conference Paper
Full-text available
This paper presents a revised version of 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 was first published in the Proceedings of the Geothermal Resources Council...
Conference Paper
Full-text available
The energetic performance of geothermal heat pump systems depends strongly on the local ground conditions. The key property dominating the performance is the ground thermal conductivity. Reliable values are needed for the design of large-scale systems. These can be determined in-situ. Site investigations, by specific equipment and procedures (wirel...
Article
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Under a framework of the Geothermal Implementing Agreement (GIA) of the International Energy Agency (IEA), an international database of hydrothermal chemistry is now under construction among the six participating countries including Iceland, Japan, South Korea, USA, Switzerland and New Zealand. The pH value of thermal water in Iceland shows 9 or 10...
Article
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...
Conference Paper
Full-text available
The Geothermal Implementing Agreement (GIA) provides a framework for international geothermal cooperation under the auspices of the International Energy Agency (IEA). The promotion of sustainable utilization of geothermal energy is the main aim of the IEA-GIA’s current 5-year term. Therefore, a task was set up under Annex I (Environmental Impacts o...
Conference Paper
Full-text available
The Geothermal Implementing Agreement (GIA) provides a flexible and powerful framework for international cooperation on geothermal research and technology under the auspices of the International Energy Agency (IEA). It connects national and industry programmes for exploration, development and utilization of geothermal resources and establishes dire...
Conference Paper
Full-text available
Under the IEA-GIA Annex VIII collaborative research framework, we have devised and circulated a questionnaire to identify barriers and opportunities in promoting geothermal direct use. The twelve countries answered to the questionnaire are Australia, Canada, France, Hungary, Spain and Sweden and six original Annex VIII participating countries such...
Article
Full-text available
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 heat...
Article
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Crystalline basement can contain notable quantities of thermal/mineral waters. Knowledge about their movement and it characteristics (fluxes, velocities, trajectories) is of great relevance for subjects like waste disposal or geothermal resources. Geothermal methods enable to quantify these flow characteristics. The use and potential of several met...
Article
Full-text available
Geothermal technologies for power generation or direct use operate with little or no greenhouse gas emissions. Since no burning processes are involved they are low in CO2 emissions. Geothermal energy development has thus great CO2 emission reduction potential when substituting fossil sources of energy. Geothermal heat pumps (GHP) represent the fast...
Conference Paper
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The IEA Geothermal Implementing Agreement (GIA) is one of 10 IEA collaborative renewable energy technology projects. It provides a versatile scheme for international cooperation in geothermal R&D activities, with a focus on enhancing effectiveness through establishing direct cooperative links among geothermal experts in the participating countries,...
Article
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Hungary has favorable geothermal conditions. The paper discusses the thermal and hydrogeologic conditions of the Neogene groundwater reservoir below the Great Hungarian Plain. In the exploration of the reservoir one of the most problematic issues, is the interaction between gravity-driven and overpressured flow regimes, especially along conductive...
Article
Full-text available
Airborne gamma‐spectrometry is able to obtain fast radiological information over large areas. The airborne gamma‐spectrometry unit deployed in Switzerland by the Swiss National Emergency Operations Centre (NEOC) consists of a Swiss army Super Puma helicopter equipped with four NaI‐Detectors with a total volume of 17 liters, associated electronics a...
Article
Annually since 1989, biannually since 1994 the sites of the Swiss nuclear facilities are surveyed flying the same survey lines by airborne gamma ray spectrometry. The equipment and the data processing software used for those surveys were built and developed at the Institute of Geophysics, ETH Zurich. For mapping the ground radiation around the nucl...
Conference Paper
Full-text available
The International Energy Agency (IEA) Implementing Agreement for a Cooperative Programme on Geothermal Research and Technology (GIA) is now in its 11th year, with a growing membership (17) of participating countries and industry partners. The wideranging and expanding efforts of the IEA-GIA are targeted towards accelerating sustainable development...
Article
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Electricity is produced by geothermal in 24 countries, five of which obtain 15-22% of their national electricity production from geothermal energy. Direct application of geothermal energy (for heating, bathing etc.) has been reported by 72 countries. By the end of 2004, the worldwide use of geothermal energy was 57 TWh/yr of electricity and 76 TWh/...
Article
Full-text available
Deep tunnels drain the rock mass above them; often large amounts of ingressing warm water flow out to the portals. Due to the elevated temperature these waters cannot be disposed in the surroundings without furtherr cooling, however the heat content (of water and/or warm air) can be used for various applications. Examples from Switzerland demonstra...
Article
Full-text available
The geothermal conditions and processes in the Rhine Graben in Germany, are discussed. The Rhine Graben has generally favorable conditions for geothermal energy development and utilization, generally elevated subsurface temperatures, regional aquifers at suitable depth. The Rhine Graben, being part of the European mid-continental rift system, is ch...
Article
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Geothermal energy is a classified as a renewable resource, where "renewable" describes a characteristic of the resource: the energy removed from the resource is continuously replaced by more energy on time scales similar to those required for energy removal. Consequently, geothermal exploitation is not a "mining" process. Geothermal energy can be u...
Conference Paper
Full-text available
Strategies to successfully manage geothermal fields in the long term will optimize sustainability and promote beneficial environmental effects. Sustainable development may involve cyclic utilization. Factors to consider will include time-scales of depletion and recovery, and rates of mass and heat recharge. Practical environmental enhancement strat...
Article
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The immense store of heat in the earth (∼1013 EJ), provided mainly by decay of natural radioisotopes, is the ultimate source for geothermal resources. It results in a global terrestrial heat flow of 40 million MW 1, which alone would take over 109 years to exhaust the earth's heat. So, the geothermal resource base is extremely large and ubiquitous....
Article
Full-text available
Increased interest in geothermal energy has led to the need for more sophisticated analyses of available geothermal resources for heating and power production. The evaluation methods have traditionally used 1D models, but progress in computing power allows us now to perform joint interpretations that include large-scale effects of geological, topog...
Article
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Surface heat flow measurements over active geothermal systems indicate strongly positive thermal anomalies. Whereas in “normal“ geothermal settings, the surface heat flow is usually below 100–120 mW m−2, in active geothermal areas heat flow values as high as several watts per meter squared can be found. Systematic interpretation of heat flow patter...
Article
Airborne gamma spectrometry is a technique especially useful for environmental monitoring and emergency preparedness. Because time is a critical factor in emergency response a fast data processing and mapping software is needed, which also supports online monitoring and data processing features. Therefore a new online data processing and mapping so...
Article
Full-text available
At WGC 1995 in Florence a paper was presented that brought to the attention of the worldwide geothermal community the increasing activity in geothermal heat pumps. With increasing pressures for reductions in building energy consumption and rising targets for reductions in CO2 emissions from buildings, the drivers for installing geothermal heat pump...
Article
Full-text available
Sustainability and renewability aspects of a group of borehole heat exchangers (BHE) are treated by numerical model simulations. The software FRACTure (Kohl and Hopkirk, 1995) is used as the modeling tool which implies transient, coupled heat and mass transfer, rock mechanics and rock/water interaction in 3D. The tool is equipped with a semiautomat...