The Ohaaki Geothermal field is situated in the Taupo Volcanic Zone of New Zealand. It was the second geothermal field in New Zealand to be developed and is used primarily for electricity generation. Wells were first drilled in the Ohaaki field during the early 1960’s. After a period of well testing following drilling, there was a long period of field recovery until steam production for electric...

Detailed and preliminary field investigations delineating the most recent fault ruptures in vicinity of the Dixie Valley, Beowawe, and Bradys geothermal fields allow an assessment of static stress changes and their possible influences on the geothermal environments. Our models for the Dixie Valley and Beowawe regions show increased failure stress on faults and fractures associated with the geot...

Directional drilling systems generate complex curved boreholes in the earth’s crust for the exploration and harvesting of oil, gas and geothermal energy. In practice, boreholes drilled with such systems often show instability-induced borehole spiraling, which negatively affects the borehole quality and increases drag losses while drilling. This paper presents a dynamic state-feedback controller...

Due to Iceland’s location on the Mid-Atlantic ridge, the island is provided with a great amount of geothermal energy. Hence, Iceland is well on the way to becoming completely independent of fossil fuels. Whereas high-temperature areas are mainly used for electricity generation, the more frequent low-temperature areas are utilized for direct application like space heating, bathing and greenhouse...

Examination of thousands of fluid inclusion gas analyses has led us to question some working hypotheses associated with interpretations of N2/Ar ratios in geothermal volatiles. Fluid inclusion gas analyses, some confirmed by analyses of present fluids, indicate that geothermal fluids have N2 and Ar concentrations about 10 times greater than in air saturated water. Also, high N2/Ar ratios are as...

The use of geothermal resources for space heating dominates the direct use industry with approximately 37% of all direct use development. Of this, 75% is provided by district heating systems. In fact, the earliest known commercial use of geothermal energy was in Chaudes-Aigues Cantal, France, where a district heating system was built in the 14 century. Today, geothermal district space heating p...

The geochemical and isotopic (strontium, boron, radium, oxygen, hydrogen) variations of geothermal waters from five different regions in Morocco were investigated in order to evaluate the sources of solutes and the mechanisms of water-rock interaction. During 2008 to 2010, twenty-two geothermal water samples were collected from the southern, central, and northern parts of Morocco. The water sam...

Background Energy is a fundamental condition for the social growth of the community, being an essential ingredient for almost all human activities and services. During the past decade, the energy policy has been working towards more environmental-friendly renewable power plants in order to achieve maximum advantages and/or fewer impacts from the exploitation of fossil-fuel resources (Kalaiselva...

Flooded mine workings have good potential as low-enthalpy geothermal resources, which could be used for heating and cooling purposes, thus making use of the mines long after mining activity itself ceases. It would be useful to estimate the scale of the geothermal potential represented by abandoned and flooded underground mines in Europe. From a few practical considerations, a procedure has been...

Background Engineered or enhanced geothermal systems (EGS) have been promoted as a technology that exploits geothermal heat and power production from regions of the crust devoid of shallow high enthalpy reservoirs (also referred to as high-grade hydrothermal resources) (e.g., MIT 2006). The status of EGS development was reviewed by Breede et al. (2013) who reported on 14 EGS projects that were ...