Performance model to assist solar thermal power plant siting in northern Chile based on backup fuel consumption

In response to environmental awareness, Chile introduced sustainability goals in its electricity law. Power producers must deliver 5% from renewable sources by 2010 and 10% by 2024. The Chilean desert has a large available surface with one of the highest radiation levels and clearest skies in the World. These factors imply that solar power is an option for this task. However, a commercial plant requires a fossil fuel system to backup the sunlight intermittency. The authors developed a thermodynamical model to estimate the backup fraction needed in a 100 MW hybrid -solar-fossil- parabolic trough power plant. This paper presents the model aiming to predicting the performance and exploring its usefulness in assisting site selection among four locations. Since solar radiation data are only available in a monthly average, we introduced two approaches to feed the model. One data set provided an average month with identical days throughout and the other one considered an artificial month of different daylight profiles on an hourly basis for the same monthly average. We recommend a best plant location based on minimum fossil fuel backup, contributing to optimal siting from the energy perspective. Utilities will refine their policy goals more closely when a precise solar energy data set becomes available.