The conditions of heat source and heat sink in a geothermal ORC system may frequently vary due to variations in geological conditions, ambient temperature and actual operation. In this study, an off-design performance prediction model for geothermal ORC systems is developed according to special designs of critical components, and an optimal control strategy which regards the turbine guide vane ...

The use of renewable energy sources can provide a path toward sustainable development and regional energy independence. In particular, renewable-based energy autonomy constitutes a viable option in remote areas. This work presents a survey on the use of renewable energy as part of an energy autonomy plan on a Mediterranean island. The study also included personal communications with residents a...

The five Nordic countries have aggressive climate and energy policies in place and have already emerged to be leaders in renewable energy and energy efficiency. Denmark is renowned for its pioneering use of wind energy, Finland and Sweden bioenergy, Norway hydroelectricity and Iceland geothermal energy. All countries aim to be virtually “fossil free” by 2050. This study explores the Nordic ener...

In an effort to tap the vast geothermal resources of the western United States, Secretary of Energy Bill Richardson and U.S. Senator Harry Reid of Nevada recently announced a DOE initiative to expand the production and use of energy generated from heat within the earth. The new initiative is known as GeoPowering the West. During a news conference on Capitol Hill, Secretary Richardson also annou...

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%–30% since 2004, geothermal growth is only abou...

Waters located at greater depths usually exhibit high mineral content, which necessitates the use of closed systems, i.e. re-injecting them into the formation after recovering the heat. This significantly reduces investment efficiency owing to the need to drill absorption wells and to perform anti-corrosion and anti-clogging procedures. In this paper, possibilities for the efficient utilisation...

Editorial Topic 4 of the Renewable Energy Program of the Helmholtz Association focusses inter alia on the sustainable and cost-efficient use of geothermal reservoirs for base-load supply of heat and electricity by EGS. Current EGS projects show the limitations of such systems. Firstly, the localization of a potential reservoir prior to drilling still remains a major challenge. Secondly, the min...

INTRODUCTION Early humans probably used geothermal water that occurred in natural pools and hot springs for cooking, bathing and to keep warm. We have archeological evidence that the Indians of the Americas occupied sites around these geothermal resources for over 10,000 years to recuperate from battle and take refuge. Many of their oral legends describe these places and other volcanic phenomen...

Climate change has played a critical role in the evolution and structure of Earth's biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this "geothermal glacial refugia" hypothesis has yet been undertaken, but Antarctica provides a ...

An important aspect of geothermal resource assessment methodology is the development of geothermal resource models consistent with the production histories of exploited geothermal fields. The primary method applied in past United States Geological Survey (USGS) assessments was the volume method, in which the recoverable heat is estimated from the thermal energy available in a reservoir of unifo...