Geothermal Energy

Goldstein, Barry; Hiriart, Gerardo; Bertani, Ruggero; Bromley, Chris; Gutiérrez-Negrín, Luis Carlos; Huenges, Ernst; Muraoka, Hirofumi; Ragnarsson, Arni; Tester, Jefferson W.; Зуй, Владимир Игнатьевич; Blackwell, David; Demayo, Trevor; Heath, Garvin; Lee, Arthur; Lund, John W.; Mongillo, Mike; Newell, David; Sanyal, S.K.; Williamson, K.H.; Wyborne, Doone; Zemedkun, Meseret Teklemariam; Wratt, David

doi:10.1017/cbo9781139151153.008

Cited by 43 publications

(30 citation statements)

References 15 publications

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“…There are a broad range of geophysical systems for which this is an excellent approximation, including the convection of saline groundwater driven by evaporation at the upper surface (Duffy & Al-Hassan 1988;Wooding, Tyler & White 1997a;Wooding et al 1997b), and the extraction of geothermal energy driven by underground heat sources (Cheng 1978;Goldstein et al 2011). We consider a fluid that initially contains a dissolved solute at some concentration C * − .…”

Section: Overview Of Physical Systemsmentioning

confidence: 99%

Convective shutdown in a porous medium at high Rayleigh number

2013

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Convection in a closed domain driven by a dense buoyancy source along the upper boundary soon starts to wane owing to the increase of the average interior density. In this paper, theoretical and numerical models are developed of the subsequent long period of shutdown of convection in a two-dimensional porous medium at high Rayleigh number Ra. The aims of this paper are twofold. Firstly, the relationship between this slowly evolving 'one-sided' shutdown system and the statistically steady 'two-sided' Rayleigh-Bénard (RB) cell is investigated. Numerical measurements of the Nusselt number Nu from an RB cell (Hewitt et al., Phys. Rev. Lett., vol. 108, 2012, 224503) are very well described by the simple parametrization Nu = 2.75 + 0.0069Ra. This parametrization is used in theoretical box models of the one-sided shutdown system and found to give excellent agreement with high-resolution numerical simulations of this system. The dynamical structure of shutdown can also be accurately predicted by measurements from an RB cell. Results are presented for a general power-law equation of state. Secondly, these ideas are extended to model more complex physical systems, which comprise two fluid layers with an equation of state such that the solution that forms at the (moving) interface is more dense than either layer. The two fluids are either immiscible or miscible. Theoretical box models compare well with numerical simulations in the case of a flat interface between the fluids. Experimental results from a Hele-Shaw cell and numerical simulations both show that interfacial deformation can dramatically enhance the convective flux. The applicability of these results to the convective dissolution of geologically sequestered CO 2 in a saline aquifer is discussed.

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Section: Overview Of Physical Systemsmentioning

confidence: 99%

Convective shutdown in a porous medium at high Rayleigh number

2013

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“…The actual energy output is always lower than the maximum energy output since a power plant can be out of service or operating at a lower capacity due to equipment maintenance or failure or, in the case of solar or wind power, due to lack of resources. According to Goldstein et al (2011), the average CF of all operational geothermal power plants is 74.5 %, while new plants often reach 90 % or more. This is higher than the CF of coal-and gas-fired power plants and much higher than the CF of other renewable energy technologies that are dependent on weather, such as solar and wind power (Goldstein et al, 2011;U.S.…”

Section: Levelized Cost Of Energymentioning

confidence: 99%

“…According to Goldstein et al (2011), the average CF of all operational geothermal power plants is 74.5 %, while new plants often reach 90 % or more. This is higher than the CF of coal-and gas-fired power plants and much higher than the CF of other renewable energy technologies that are dependent on weather, such as solar and wind power (Goldstein et al, 2011;U.S. Energy Information Administration, 2012;REN21, 2014).…”

Section: Levelized Cost Of Energymentioning

confidence: 99%

Assessing the prospective resource base for enhanced geothermal systems in Europe

et al. 2014

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Abstract. In this study the resource base for EGS (enhanced geothermal systems) in Europe was quantified and economically constrained, applying a discounted cash-flow model to different techno-economic scenarios for future EGS in 2020EGS in , 2030EGS in , and 2050. Temperature is a critical parameter that controls the amount of thermal energy available in the subsurface. Therefore, the first step in assessing the European resource base for EGS is the construction of a subsurface temperature model of onshore Europe. Subsurface temperatures were computed to a depth of 10 km below ground level for a regular 3-D hexahedral grid with a horizontal resolution of 10 km and a vertical resolution of 250 m. Vertical conductive heat transport was considered as the main heat transfer mechanism. Surface temperature and basal heat flow were used as boundary conditions for the top and bottom of the model, respectively. If publicly available, the most recent and comprehensive regional temperature models, based on data from wells, were incorporated.With the modeled subsurface temperatures and future technical and economic scenarios, the technical potential and minimum levelized cost of energy (LCOE)

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“…Nevertheless, available major exploration methods to determine a target fracture by imaging subsurface geothermal reservoirs until the present are confined only to the resistivity and seismic surveys, where they use electromagnetic and elastic waves, respectively, both of which do not go straight on. The positioning resolutions of imaging by these methods are not so satisfactory such that the drilling of exploration wells in greenfield areas is reported to have a success rate of typically about 50 to 60 % (Goldstein et al, 2011). About half of the drilling cost is wasted.…”

Section: Resultsmentioning

confidence: 99%

Interpreting muon radiographic data in a fault zone: possible application to geothermal reservoir detection and monitoring

Tanaka

Muraoka

2013

Geosci. Instrum. Method. Data Syst.

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Abstract. Rainfall-triggered fluid flow in a mechanical fracture zone associated with a seismic fault has been estimated (Tanaka et al., 2011) using muon radiography by measuring the water position over time in response to rainfall events. In this report, the data taken by Tanaka et al. (2011) are reanalyzed to estimate the porosity distribution as a function of a distance from the fault gouge. The result shows a similar pattern of the porosity distribution as measured by borehole sampling at Nojima fault. There is a low porosity shear zone axis surrounded by porous damaged areas with density increasing with the distance from the fault gouge. The dynamic muon radiography (Tanaka et al., 2011) provides a new method to delineate both the recharge and discharge zones along the fault segment, an entire hydrothermal circulation system. This might dramatically raise the success rate for drilling of geothermal exploration wells, and it might open a new horizon in the geothermal exploration and monitoring.

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Geothermal Energy

Cited by 43 publications

References 15 publications

Convective shutdown in a porous medium at high Rayleigh number

Convective shutdown in a porous medium at high Rayleigh number

Assessing the prospective resource base for enhanced geothermal systems in Europe

Interpreting muon radiographic data in a fault zone: possible application to geothermal reservoir detection and monitoring

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