Power Generation in Cerro Prieto Geothermal Field

Abstract

In 2011 four of thirteen turbines were shut down permanently (decommissioned) due to lack of steam in Cerro Prieto reducing the installed capacity from 720 MWe to 570 MWe. Since then CFE is trying to increase energy generation by different means. In 2012 a 5MWe installed capacity power plant was installed (commissioned) in Cerro Prieto using 4 different technologies: polycrystalline panels with one and two axis tracking system, thin film panels with one axis tracking system and solar concentration panels with two axis tracking system. The solar radiation is 5.5 W/m2 in Cerro Prieto is above the average of 5.0 W/m2 in the rest of the country, plus the land was already part of the geothermal field. This project open the door for a 10MWe thermo solar plant to be commissioned in 2015 to evaporate the blow down residual water from the geothermal cooling towers and feed the steam to the Cerro Prieto pipeline grid that goes into the steam turbines in the power plants. A water treatment plant is going to be installed to remove mud and solids from the blow down before entering the thermo solar plant. Organic Rankine Cycle in Cerro Prieto has been elusive because of the high scaling silica problem, but in 2015 a new well is going to be drilled to install a deep well pump to maintain high pressurized brine into a heat exchanger and avoid silica polymerization and precipitation.