| Abstract |
Geothermal resource exploration, assessment and evaluation started through Spain in the seventies with a general geological and geochemical survey of known thermal springs and areas showing signs of thermal activity. The most interesting sites were then selected, based on geological criteria and the findings of the survey mentioned above. Over the following decades, each of the selected areas has been investigated utilizing techniques from geology, geophysics, geochemistry and related disciplines, the intensity of the investigation depending on each area's geothermal potential. Lastly, deep drilling has been done, enabling the geothermal potential of the more important areas to be evaluated. These major areas are located in the southeast (Granada, AlmerÌa and Murcia), northeast (Barcelona, Gerona and Tarragona), northwest (Orense, Pontevedra and Lugo) and center (Madrid) of the Iberian Peninsula. Other, more minor areas located in Albacete, LÈrida, LeÛn, Burgos and Mallorca have also been investigated. The geothermal resources evaluated in all these cases exhibit low temperatures, 50-90 ?C. The only area where high-temperature fluids might possibly exist at depth lies in the volcanic archipelago of the Canary Islands. Hot dry rock resources have been evaluated on the islands of Lanzarote and La Palma. On the island of Tenerife, the presence of high-temperature areas has been investigated, but no commercially viable geothermal reservoirs have been found. Low-temperature geothermal sites are currently being exploited on a small scale. For example, geothermal fluids are being used for heating and to provide hot water to spa buildings in Lugo, Arnedillo (in La Rioja), Fitero (in Navarra), MontbriÛ del Camp (in Tarragona), Archena (in Murcia) and Sierra Alhamilla (in AlmerÌa). In Orense and LÈrida, geothermal waters are being used to heat homes and schools. Greenhouses are being geothermally heated at MontbriÛ del Camp (Tarragona), Cartagena and MazarrÛn (in Murcia), and Z?jar (in Granada); these facilities cover a total area of over 100,000 m2. |