This paper reports on the first phase of the Colón Solar Project, originally conceived as the hybrid
repowering of an existing thermal power plant, with the addition of a gas turbine in a topping configuration
integrating thermal energy (steam) produced by a solar system. However, the project developed in a changing
economic environment, in which a new legal structure, still incomplete, as of January, 1998 has liberalized the
electricity generation market. This forced the original configuration to be modified, resulting in an all-new combined
cycle with solar energy integrated into a Heat Recovery Boiler. Basic plant engineering placed special emphasis on the
most important solar components (heliostat and receiver), and an economic analysis showed that the plant is profitable
under the assumptions of the analysis. Nevertheless, the relatively low IRR, as well as the uncertainty of realization of
some of those assumptions, made the utility postpone its decision to build the plant
