Greece is rich in geothermal resources due to active extensional tectonics and volcanic activity. In a presentation given in 2017, Dr. Apostolos Arvanitis, Geologist at the Institute of Geology and Mineral Exploration, shared a fantastic overview on geothermal energy, exploration, fields, exploitation and the legal framework for development.
Geothermal exploration in Greece began by IGME (Institute of Geology and Mineral Exploration of Greece) in the early 1970’s. Two high enthalpy geothermal fields (temperatures 280-350 degrees Celisius at depths of 1,000-1,816 m) have been identified in Milos and Nisyros islands located along the South Aegean Active Volcanic Arc with proven geothermal potential 30 MWe and estimated possible potential >200 MWe.
A large number of low enthalpy fields have been identified throughout the country mostly associated with grabens, extensional tectonics and deep water circulation along fault systems. In spite of the enormous geothermal potential, the exploitation is still limited.
There is no power generation due to negative attitude of the inhabitants of Milos and Nisyros islands. The direct uses of geothermal energy include greenhouse/soil/space heating, aquaculture, dehydration, balneotherapy and ground-source heat pumps (GSHP).
The total installed capacity is estimated to be at 231.76 MWt (March 2016) and the GSHP applications represent more than 60% of that total.
The GSHP market has grown rapidly since 2007 including mostly installations of heating and cooling of residential, office and public buildings as well as hotels, swimming pools and a few agriculture/industrial applications. The geothermal exploration and exploitation in Greece are defined by Geothermal Law 3175/2003 (“Exploitation of geothermal potential, district heating and other provisions”) and the relative Ministerial Decrees.
A few amendments were made by Law 3734/2009 (article 37). The current geothermal legislation classifies the geothermal fields into “high” (T>90oC) or “low temperature” (T?90oC) and “proven” or “probable” fields.
Nowadays, 32 areas have been officially characterized as “geothermal fields” corresponding to more than 40 “proven/probable” and “high/low temperature” geothermal fields.
Licenses for exploration, exploitation and management of a field (or part of it) are provided by the Decentralized Administrations (for low temperature fields) or directly from the Ministry of Environment and Energy (for high temperature fields). Balneology and the “development of curative tourism” are defined by Law 3498/2006 and the relative Ministerial Decrees.
Finally, the exploitation of very shallow geothermal potential using GSHP systems is mentioned in Law 3175/2003 and the procedures are defined by Ministerial Decree (Government Gazette, 1249/B/24 June 2009).