With a total installed energy capacity of 951 MWe (for 2018) and four developed geothermal fields, i.e. Cerro Prieto, Los Azufres, Los Humeros, and Las Tres Virgenes, Mexico is currently one of the top geothermal power producers worldwide. Installed geothermal power represents around 2% of the total installed electric capacity. In Mexico, the generation, transmission, and distribution of electric power are carried out by two public utilities i.e. the Comision Federal de Electricidad (CFE) and the Companıa de Luz y Fuerza (CLF).
Fig. 1. Location of potential hydrothermal sites and geothermal fields within the Mexican territory (Birkle P., 2007)
Geothermal energy is used across Mexico almost entirely for electricity generation. Its direct uses still remain under development and are mainly utilized for balneology. In the period between 1963 to the end of 2008, 556 exploration, production, and injection geothermal wells, have been drilled with a combined depth of 1188 km and an average depth of around 2137 m per well. Approximately 66% of all wells and 73% of the combined length have been constructed in the Cerro Prieto geothermal field, which currently accounts for 75% of the geothermal-electric installed capacity and 73% of electric generation. It is worth noticing that the average depth of wells in the Cerro Prieto, the Los Humeros and even the Las Tres Virgenes is similar, whereas wells at the Los Azufres are much shallower, with a total average depth of approximately 1351 m. The reservoir rocks of Mexico’s high-temperature geothermal systems are mostly sandstones, andesites, and granodiorites. From 2000, CFE started performing the matrix acidizing technique in order to improve the production and injection capacity of deep wells in various geothermal fields across Mexico. Since that time, many wells have been acidized, inducing gains in production and injection capacity.
Fig. 2. Los Humeros geothermal field (photo: Michal Kruszewski)
The Cerro Prieto field is the oldest in Mexico and the largest known water-dominated geothermal field in the world with 720 MWe installed capacity and 138 production and 13 injection wells (as for 2009). The first unit installed at the Cerro Prieto, located in the part of the field known as CP-I, was commissioned in the April of 1973. The Cerro Prieto geothermal field is located within a pull-apart basin, locally limited by the Cerro Prieto and Imperial faults, both being a part of the San Andreas Fault System. The annual average production rate per well in 2009 amounted to approximately 29 t/h.
Extensive exploratory studies of geology, geochemistry, and geophysics made it possible to access various areas of high, medium and low enthalpy geothermal potential interest in Mexico of around 500 MW. The most likely soon-to-be-developed areas of Mexico are:
Using available geothermal energy resources across the territory of Mexico can significantly decrease the dependence on fossil fuels, reduce the emissions of greenhouse gases and increase the added value of economic activities. Mexico, due to its very favorable location, has immense potential in renewable energy development, especially high-temperature geothermal resources, and provides ample opportunities to be exploited and meet the challenges of global warming.
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