Solar panels: Real efficiencies, potential productions and payback periods for major Australian cities

In spite of continuous campaign and efforts large scale adoptions of solar panels are yet to be materialised, mainly due to lack of confidence on potential energy savings. This paper presents real efficiencies achieved from four houses in two Australian cities; Melbourne and Adelaide. Based on actual solar energy productions and actual incoming solar radiations during a monitoring period, efficiencies of solar panels installed in the selected houses were calculated. It was found that among the four monitored houses, a maximum efficiency of 7% was achieved. Considering this maximum achievable efficiency and annual average incoming solar radiations, potentials of energy savings for eight major cities of Australia are presented considering two different solar panel systems; 2 kW and 5 kW. It was found that for a typical 4-members household winter-demand, a 2 kW system and 5 kW system is expected to generate 19-29% and 49-73% of total energy. In addition, considering the current costs and expected savings, payback periods of different sized solar systems are presented for the eight cities.