FAQ

 

Below you 'll find answers to most commonly asked questions  of the use of geothermal energy in heating and cooling networks.
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General Questions

Three main types of geothermal technologies may consider for district heating and cooling systems: Direct use geothermal, Deep and enhanced geothermal systems (EGS) and Ground source heat pumps. EGS can be decribed as engineered reservoirs that have been created to extract economical amounts of heat from low permeability and/or porosity geothermal resources. Schulte et al. (2010) defined the typical geological settings for EGS, varying from igneous (e.g. Iceland), metamorphic (e.g. Lardarello, Italy), magmatic (e.g. Soultz, France) and sedimentary (e.g. Groß Schönebeck and Horstberg, Germany).

Schulte T, Zimmermann G, Vuataz F, Portier S, Tischner T, Junker R, Jatho R, Huenges E: Enhancing geothermal reservoirs. In Geothermal energy systems. Edited by: Huenges E. Wiley, Weinheim; 2010

Katrin Breede, Khatia Dzebisashvili, Xiaolei Liu and Gioia Falcone: A systematic review of enhanced (or engineered) geothermal systems: past, present and future, Geothermal Energy 2013, 1:4
Geothermal energy use for heating and cooling is supported by the third generation of DH systems, which was introduced in the 1970s and took a major share of all extensions in the 1980s and beyond (Lund, H., et al, 2014). Today 4th and 5th generation of district heating networks is available. The 4th generation of district heating networks is characterized by lower temperatures and can allow easier integration of cost-efficient renewable energy technologies (like solar energy or geothermal heat pumps) which are not linked to combustion processes. A further division of 4th generation systems can be made between so-called low temperature district heating (LTDH) and ultra-low temperature district heating (ULTDH). LTDH networks are usually characterized by supply temperatures in the range 50–70 ◦C, while ULTDH networks have supply temperatures below 50 ◦C.
Marco Pellegrini and Augusto Bianchini, The Innovative Concept of Cold District Heating Networks: A Literature Review, Energies, 2018
More than 25% of the EU population lives in areas directly suitable for Geothermal District Heating. There is a large potential, with GeoDH systems in operation in 22 European countries. Geothermal generation has its roots in Europe.
http://geodh.eu
Geothermal district heating and cooling systems can be found here
Our COST Action Geothermal-DHC will provide information on additional case studies not included in this map
Geothermal district heating (GDH) is the use of geothermal energy to provide heat to buildings and industry through a distribution network. Geothermal energy can be utilized for space heating and cooling, domestic hot water supply, and industrial process heat requirements by district heating using peaking stations, a distribution system, central pumping stations, and in-building equipment (heat exchangers, circulation pumps, etc.).
Ibrahim Dincer, Hasan Ozcan, in Comprehensive Energy Systems, 2018
Geothermal energy systems can provide environmentally friendly, reliable and affordable hot water for DH systems (Tester et al., 2006; Thorsteinsson, 2008; Reber et al., 2014). They have a small land area footprint, are scalable in size and emit few to zero greenhouse gas emissions. Further, they utilize low-tech technology and offer dispatchable baseload capacity and cascading opportunities.
J.W. Tester, ... M.Z. Lukawski, in Advanced District Heating and Cooling (DHC) Systems, 2016
Geothermal district heating systems are classified into two types depending on the utilization of the geothermal energy. If it is used indirectly by transferring the geothermal heat to the secondary system via heat exchangers, the district heating system is called the primary system. If the geothermal energy is utilized directly in the house heating systems, the district system is called the secondary system.
Ibrahim Dincer, Muhammad F. Ezzat, in Comprehensive Energy Systems, 2018.