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Geothermal Country Update for Ecuador, 2000-2005

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Geothermal Country Update for Ecuador, 2000-2005 Proceedings World Geothermal Congress 2005 Antalya, Turkey, 24-29 April 2005 Geothermal Country Update for Ecuador, 2000-2005 Bernardo Beate, Rodney Salgado Escuela Politecnica Nacional, Dept de Recursos Minerales, PO Box 17-01-2759, Quito/Ecuador [email protected] Keywords: Ecuador, geothermal exploration, heat source, The energy market is dominated by Hydro (50.6 %) and hot springs of Ecuador, assessment of geothermal prospects, Fossil Fuel (49.4 %) generation, with a total installed use of geothermal energy. capacity of 3451 Mwe, yielding a gross electricity production of 12357 GWh/yr (as of Dec 2002). ABSTRACT Production from renewable energy sources in Ecuador, Due mainly to its favorable geodynamic setting along the including geothermal, solar and wind, is still neglegible, but active convergent plate margin of Southamerica, is planned to increase in the future. The Tufiño-Chiles characterized by a broad continental volcanic arc with geothermal prospect owns the especial status of Bi-National numerous active volcanoes and intense seismicity, and to Project, due to its location on the Ecuador-Colombia border. the elevated oil prices of the time, Ecuador started the This and several other high and low-medium temperature exploration of its geothermal resources about 30 years ago, geothermal prospects in Ecuador await state and private aiming on high enthalpy prospects, suitable for electricity investment to be developed in order to lessen the production. dependence on fossil fuel use. Finally, in Ecuador, geothermal energy is challenged to be cost-efficient in front Exploration for geothermal resources was carried out from of an abundant hydro resource, as well as to be the mid 1970´s through the early 1990´s by ecuadorean environmentally safe. government institutions (former INECEL and INE) with the aid of foreign technical assistance programs (mainly OLADE, IAEA, UNDP). 1. INTRODUCTION Ecuador needs energy resources to keep pace with the fast Reconnaissance studies focused on areas with recent track of globalization, therefore it is the government´s volcanic and tectonic activity in the Plio-Quaternary priority to explore and develop indigenous energy resources, volcanic arc, which covers most of the northern andean both conventional and renewable, which includes highlands of Ecuador. Results from geo-scientific surveys geothermal energy. Ecuador is a democratic republic, revealed the presence of several active hydrothermal located on the western edge of equatorial Southamerica; it systems. Tufiño-Chiles, Chachimbiro and Chalupas has 12 156 608 inhabitants living in a territory of 256 370 appeared as the most promissing prospects, with deep km2 (INEC 2001); the official language is Spanish and the temperatures in excess of 200 °C and a combined potential GNP was 17 302 986 000.- USD for the year 2002. of about 500 Mwe. This potential was inferred from surface data only, since no geothermal exploratory wells have been Lead government agencies involved in geothermal energy drilled yet in Ecuador. are the MEM (Ministerio de Energía y Minas - Ministry of Energy and Mines), CONELEC (Consejo Nacional de A dozen other geothermal prospects, related to silicic Electricidad – National Council for Electricity) and the calderas and /or evolved stratovolcanoes can substantially CNRH (Consejo Nacional de Recursos Hídricos – National increase the inferred potential, but quantitative data are Council for Water Resources). scarce or even nonexistent. Other areas of interest, including the Galapagos hot spot islands, still remain unexplored. Geothermal Energy is considered a renewable type of energy and has a special status to encourage its development Low to medium temperature resources are abundant along involving private investment. This policy is part of the the volcanic arc and are mainly related to recent NNE strike modernization trend of the ecuadorean state. slip faulting and local pull appart structures; these geothermal resources are not confined to the volcanic In the following pages we present an overview of Ecuador´s highlands, but are also present in the fore-arc plains as well geological setting, a description of the geothermal resources as in back-arc areas, mostly related to deep cutting basement and potential, together with the history of exploration, the faults. state of geothermal utilization and a discussion of the actual and future development. As for now, geothermal utilization in Ecuador is currently restricted to direct use in swimming pools, only. Basic 2. OVERVIEW OF ECUADOR´S GEOLOGICAL research, applicable to geothermal is done, scarcely, at few SETTING universities. Geographically and geomorphologically, mainland Ecuador Geothermal is considered a renewable non-conventional consists of three regions: the coastal plains or COSTA, the type of energy, together with solar, wind, biomass and Andes mountain chain or SIERRA and the Amazon basin or others. CONELEC and MEM (Ministry of Energy and ORIENTE. A fourth region comprises the Galapagos Islands, Mines) are the leading national agencies for energy issues located about 1000 km W in the Pacific Ocean (see fig.1) and promote the use of renewable resoures by assigning them a especial status regarding priority for development and connection to the national grid, as well as a favorable price for selling electricity. 1 Beate and Salgado 90ºW 88ºW 86ºW 84ºW 82ºW 80ºW 78ºW 4ºN 16 2400 E 2 Cocos MALPELO RIFT m N 7 (Extint) Ridge O Z 15 CO E LOMBIA 3 R U 2 Key 6 T 2 C 60-70 A 12 mm/yr R 3 0 4 F 0 Thrust fault 0 A 1 3 10 m 2ºN Normal fault 3 M 4 A 10 22 N Dextral strike-slip fault 2 A 6 Galapagos Rift P 12 Main city 7 2 H 2 C Quaternary volcano N 3 10 E O 70 R C Active volcano m T V 3 m/ yr A R I 4 Quito 0º 18 Magnetic isochrones in Ma 12 O GALAPAGOS D 2400m Bathimetry (depth below sea level) A ISLANDS U Ca C 1000m rnegie E Elevation in masl (HOT SPOT) Ridge Costa Oriente CO Coordillera Occidental 2400 CR Coordillera Real m Sierra 80ºW Guay IAV Interandean Valley 17 aquil 2ºS COCOS PLATE 18 R ECUADOR C 0º 19 SOUTH Redrawn after the Plate Tectonic AMERICAN 20 20 N E 0 AZCA N 0 Map of the Circum-Pacific PLATE O 0 PLA Z 1 NAZCA TE 2 RE m Region (1981) amd modified 2 TU PLATE AC 4ºS from Spikings et al., 2001 FR LVA JA ST 2 Huancabamba RI U 9 G CR PLATE N Deflection LO AL TIC R TAR FA 2 PERU AN 5 TE PLA Fig. 1 Geodynamic Setting of Ecuador, showing mainland Ecuador on South American plate and the Galapagos Islands on Nazca plate The Andes are the backbone of the country. They were extensive volcanism (Lonsdale, 1978). The northern half of formed by multiple accretion since Jurassic times (Aspden the country is part of the North Andean Block, which moves &Litherland, 1992; Eguez and Aspden, 1993), and consists at 6-10 mm/yr in a NE direction along strike-slip faults of two paralell NNE striking mountain chains: a) the entering the gulf of Guayaquil (Ego et al.,1993). This Cordillera Real (CR or Eastern Cordillera), made up of compressive regime formed several intramontane basins of sublinear belts of metamorphic rocks intruded by both, S pull-appart nature between the two cordilleras since the and I – type granitoids of early Mesozoic age. b) the Miocene. The IAV has been formed as a spindle shaped Cordillera Occidental (CO or Western Cordillera) consists of basin by displacement along a restraining bend in a late Mesozoic to Early-Cenozoic basalts and volcaniclastics, transpressive regime since about 6 My due to an increase in which represent accreted oceanic terrains (Hughes and the coupling of Carnegie ridge in the subduction zone Pilatasig, 2002); these rocks are intruded by Tertiary (Spinkings, 2001; Winkler, 2002; Villagomez, 2002). This granitoids. Both cordilleras have been uplifted and are setting, as well as the extensive Quaternary volcanism, capped by late Tertiary volcanics. Between the two favours the presence of high heat-flow anomalies along the Cordilleras is the Interandean Valley (IAV), which is ecuadorean Andes, hence, the availability of heat sources for laterally bonded by active faults, mostly thrust faults, and geothermal systems to exit is plentyful. comprises thick Late-Tertiary to Recent volcaniclastic and epiclastic sedimentary sequences. Covering both Cordilleras 3. GEOTHERMAL RESOURCES AND POTENTIAL in its northern half, a well developed, broad, calk-alkaline The Reconnaisance Study of the Geothermal Resources of volcanic arc extends northwards into Colombia (Barberi et Ecuador, carried out from 1979 to 1980, started geothermal al., 1988; Hall & Beate, 1991). The arc is of Quaternary age exploration in Ecuador. It was aimed to find high- and consists of more than 50 volcanoes, of which at least 30 temperature hydrothermal systems along the Andes in the are active. The southern part of the Andes shows only areas of recent volcanism, following the methodology extinct volcanic activity due to the flattening of the slab recommended by OLADE (1978). The report since late Miocene (Gutscher et al., 2000). (INECEL/OLADE 1980) produced by INECEL (Instituto Ecuatoriano de Electrificación, now defunct) and OLADE The Oriente is an extensive sedimentary basin, which (Organización Latinoamericana de Energía), together with overlies cratonic basement (Baldock, 1982) Older rocks AQUATER (Italy) and BRGM (France), summarized the include Jurassic batholiths and a Cretaceous carbonate areas of interest in two main groups: Group A (high- platform, covered by Tertiary epiclastic sediments. Large temperature; Tufiño, Chachimbiro and Chalupas) and Group thrust folds cut the sequence with a NS strike. B (low-temperature; Ilaló, Chimborazo and Cuenca). INECEL, through its Geothermal Project, carried out follow- Quaternary alcaline volcanoes are present along the central up prefeasibility studies between1981 and 1992, first at W margin of the basin in a back-arc setting.
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