Restoration of the generating capacity of the Guatape hydroelectric powerplant

Since 1978, when the second stage of the Guatape Hydroelectric Powerplant (560 MW), owned by Empresas Públicas de Medellin, started operating, some problems in the performance of the refrigeration system of the units were noticed. It was found, after having devoted a long time to investigations, that the water used for refrigeration, taken from the reservoir, gave rise to scales in the heat exchanger tubes. That entailed a rapid decreasing of the tube capacity, and compelled the operations personnel to frequently shut down the units to clean the exchangers, with serious technical and economical consequences. After having identified the problem, different solutions have been attempted, such as physical and chemical treatments in the reservoir, the waterways, the pump pits, the refrigeration system, and even in the tailrace tunnels. It was finally decided, after having analyzed different alternatives, to redesign the system and change the water source, as the only solution guaranteeing a reliable operation of a public facility fundamental for the electric system of the country.