PRACTICAL METHOD to Estimate Energy Potential Generated by Photovoltaic Cells: Practice Case at Merida City

Abstract

Nowadays, the use of renewable energy continues growing, particularly the solar photovoltaic, due to photovoltaic cells cost reduction and the grid connection ability, however a major challenge to encourage their use, is to rely on a method to estimate the potential energy generated by solar cells at specific location, it is important to sustain its viability or estimate generation projects in large and small scale. The photovoltaic cell conversion efficiency (η) and the maximum power point generated (Pmpp), is reduced by radiation (E) and temperature (T) variation, affecting the output current (Io) and output voltage (Vo) respectively. This paper presents a practical method to calculate the energy generated per unit area based on cell mathematical model (P-N junction), the V-I and P-I characteristic curves, solar cell manufacturer data sheet, and a specific location climate database. This method provides the energy generated (kWhr) per square meter, per year, and the photovoltaic cell real conversion efficiency. A practice case at Merida City, México, is presented to expose the application method, for a five different 110W photovoltaic panel. As a result, the real conversion efficiency is lower almost 50% than conversion efficiency under standard test conditions (T=25oC, E=1000W/m2).