ISSN 0003-701X, Applied Solar Energy, 2009, Vol. 45, No. 3, pp. 166–175. © Allerton Press, Inc., 2009. 166 1 1. INTRODUCTION Over the last years energy and environmental issues became worldwide concerns. Renewable sources of energy are the need and solution in today’s lack of fos- sil fuels and “green” issues. Solar energy is considered one of the most dominant and “pure” forms of energy. Photovoltaic modules are the functional unit of the solar energy. This paper, through Life Cycle Analysis (LCA) on energy aspects of a PV module producing power 185 Wp, sized 1660 × 830 × 50 mm (H L W) and weighted 17 kg, focuses on the calculation of the time needed for a PV module to reimburse the amount of energy consumed in order to be produced. The indica- tor of the energy reimbursement in this research is the Energy Payback Ratio or the Energy Payback Time (EPR/EPBT) [1]. The information needed for the LCA and the EPR were drafted from previous researches [1, 2] and the use of two softwares in order to verify the results: (1) CES EduPack 2008, eco-audit tool, Granta (energy inspection) (2) RETScreen 2005, RETScreen (estimation of the energy ascription of the PV panel). LCA studies the environmental aspects and potential impacts throughout a product’s life (i.e. cradle-to-grave) from raw material acquisition through use and disposal. The general categories or environmental impacts need- ing consideration include resource use, human health and ecological consequences (ISO 14040). In bounds of LCA and specifically on energy aspects, EPR is placed among, which is an indicator estimating the energy reimbursement of a product, spe- 1 The article is published in the original. cifically in this paper of a PV panel. EPR is defined as the fractal of the energy spent to produce the PV mod- ule to the energy returned to the line through the mod- ule’s life cycle, as expressed by the fractal [1]: Material procurement energy + production energy + lamination energy + operation energy + service energy Energy produced over a given product lifetime. Usually the measurement of the EPR for a PV mod- ule is done in years or months. In this paper an LCA study, focused on energy aspects, for a 185 Wp PV module installed in north eastern Greece, in the city of Xanthi, has been accom- plished. A description of the functional unit and the cli- mate conditions of the research in addition to the struc- ture, the materials and the processes of the photovoltaic is presented in Section 2. The energy analysis based on two methods is developed in Section 3. Afterwards, the estimation of the EPR, in both ways, is worked out in Section 4 to conclude in Section 5 where the results and conclusions are presented. 2. PHOTOVOLTAIC MODULE A life-cycle assessment generally begins with the definition of the goal and the scope of the assessment to be undertaken. The goal of this study is the estimation of the Energy Payback Ratio. Along, the scope refers to the conditions under which the goal is being accom- plished, analytically, the functional unit that is studied and the climate conditions. In particular, the goal set is the estimation and veri- fication, according to previous researches [1, 2] as well, of the time needed for a PV module of specified dimen- Estimation of the Energy Payback Time (EPR) for a PV Module Installed in North Eastern Greece 1 P. N. Botsaris and F. Filippidou Democritus University of Thrace, School of Engineering Department of Production Engineering and Management, Greece Received July 05, 2009 Abstract—Energy Payback Time is defined as the time necessary for a photovoltaic panel to generate the equivalent amount of energy used to produce it. The goal of this paper is to estimate the energy payback ratio for a 185*Wp multicrystalline photovoltaic module with specific characteristics and structure. The methodol- ogy followed was attested in two ways of extracting the EPR (Energy Payback Ratio). The first one was based on precedent researches, whereas the second one was based on the use of two softwares (CES EduPack 2008 and RETScreen). The results, then, were compared and confirmed in order to deal with crossbred information. DOI: 10.3103/S0003701X09030086 SOLAR POWER PLANTS AND THEIR APPLICATION