| Abstract |
During the last few years, new legal dispositions have favored the promotion of non-conventional energy sources in Colombia: The law 697 of 2001 declared the rational and efficient use of energy and the utilization of non-conventional energy sources, as a social and public interest matter as well as a national convenience issue. The same law, demands stimulus for developing non-conventional energy sources from the government. The edict 3683 dated December 2003, regulates the promotion of non-conventional energy sources, inside the frame of sustainable development, following the recommendations of The Johannesburg Summit, in which Colombia participated. Since 2000 the geothermal project of INGEOMINAS which is the institution in charge of the geothermal exploration in Colombia, have worked on two topics: 1) The inventory of hot springs, in two areas: Cerro Bravo - Cerro MachÌn Volcanic Complex and Cundinamarca Department and 2) the first stage of exploration two areas: Azufral volcano (NariÒo Department) Paipa geothermal area (Boyac· Department). The inventory of hot springs at Cerro Bravo - Cerro MachÌn Volcanic Complex was based in the reinterpretation of the geochemical existing information. The Santa Rosa de Cabal group, constituted by the springs of San Vicente and Santa Rosa sectors, revealed the highest interest as an energy resource given the highest geochemical temperatures inferred in the reservoir. This is proposed as an independent system from Nevado del Ruiz. The inventory of hot springs from Cundinamarca department indicate the existence of this surface manifestatons at 27 municipalities, from which 52 mineral and hot springs were characterized. The spatial distribution of the springs shows a trend to increase their temperature towards the East of the Department, reaching a maximum of 73.6?C at Paratebueno locality. From the geochemistry of the springs, Cundinamarca has geothermal resources of low temperature related to a normal geothermal gradient. The first stage of exploration at Azufral volcano included the preparation of the geological cartography of the area as well as the updating of the chemical composition of hot springs. The stratigraphy of Quaternary deposits together with a geochronological study allowed defining a new geological formation. The geochemistry of the springs shows a probable contribution of a saline non geothermal source. The quartz geothermometers indicate a minimum probable temperature of 180?C. At Paipa geothermal area the work included geological studies of cartography, tectonics and volcanological, electromagnetic surveys and geochemistry of the aqueous phase of the hot springs. From them a high temperature geothermal system is proposed with a magmatic heat source, an upflow controlled by deep faults and a shallow mixing process with a highly sodium sulfate mineralized water which "masks" the chemical composition of the deep reservoir fluid. |