Performance model to assist solar thermal power plant siting in northern Chile based on backup fuel consumption Teresita Larraı ´n, Rodrigo Escobar * , Julio Vergara Departamento de Ingenierı ´a Meca ´nica y Metalu ´rgica, Pontificia Universidad Cato ´lica de Chile, Vicun ˜a Mackenna 4860, Macul, Santiago, Chile article info Article history: Received 5 January 2009 Accepted 10 January 2010 Available online 3 March 2010 Keywords: Concentrated solar power Utilizability Chile abstract 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. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction The last Intergovernmental Panel on Climate Change (IPCC) report has confirmed that a global warming process is underway, reflected in global temperature increases, widespread melting of snow and ice reservoirs, average sea level rising, and other conse- quences [1] directly related with greenhouse gases (GHG), which dominate the radiative forcing of the climate system producing for higher concentrations a warming rate increase. The atmospheric concentration of GHG such as CO 2 , methane and nitrous oxide which are product of human activities has increased by 70% between 1970 and 2004, with current values far exceeding pre- industrial levels. Then, human activities are the principal cause of these processes, mainly due to the sustained use of fossil fuels. As fossil fuel utilization presents serious environmental impacts, climate change could be stopped with the replacement with other energy sources. An additional problem is that fossil fuels, the main energy sources in use by today’s society, are subject to resource depletion due to their non-renewable status. As a consequence, a peak of fossil fuel production is expected, which will force society to seek alternative energy resources not subject to depletion [2]. An exact date of fossil fuel peak production cannot be accurately pre- dicted, although experts seem to reach a consensus that it will eventually happen within the next two decades [3,4]. Considering both the environmental and depletion issues of fossil fuels, it is therefore necessary to find adequate substitutes and plan a transition to other energy sources, which must meet adequate price levels in order to ensure proper access by the population, provide minimum environmental impact, and be available in sufficient quantities in order to satisfy demand ensuring security of energy supply [4]. Within renewable energy sources, solar energy is an attractive alternative for some countries, as it takes advantage of an infinite source of energy, the sun. Power generation systems that use solar energy as a source can result in greatly reduced equivalent GHG emissions. Additionally, in most cases they are not subject to land use issues or controversies, since the best locations for installing these systems are deserts or arid regions, which generally present low population densities. Chile is an example of a country that could benefit from solar thermal power generation, as it exhibits both the need for electric energy and the proper conditions for ample solar power plant deployment. The main objective of the present study is to present a solar power plant model for computing its electricity generation and the fossil fuel backup required to sustain continuous operation. The * Corresponding author. Tel.: þ56 2 3545478; fax: þ56 2 3545828. E-mail address: rescobar@ing.puc.cl (R. Escobar). Contents lists available at ScienceDirect Renewable Energy journal homepage: www.elsevier.com/locate/renene 0960-1481/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.renene.2010.01.008 Renewable Energy 35 (2010) 1632–1643