SIMPLIFIED LIFE-CYCLE ANALYSIS OF PV SYSTEMS IN BUILDINGS - PRESENT SITUATION AND FUTURE-TRENDS

The integration of photovoltaic (PV) systems in buildings shows severa l advantages compared to conventional PV power plants, The main object ives of the present study are the quantitative evaluation of the benef its of building-integrated PV systems over their entire life-cycle and the identification of best solutions to maximize their energy efficie ncy and CO2 mitigation potential. In order to achieve these objectives , a simplified life-cycle analysis (LCA) has Been carried oat, Firstly , a number of existing applications have been studied. Secondly, a par ametric analysis of possible improvements in the balance-of-system (BO S) has been developed. Finally, the two steps have been combined,Pith the analysis of crystalline silicon technologies. Results are reported in terms of sever al indicators: energy pay-back time, CO2 yield and specific CO2 emissions, The indicators show that the integration of PV systems irt buildings clearly, increases the environmental benefits o f present PV technology. These benefits will further increase with fut ure PV technologies, Future optimized PV roof-integrated systems are e xpected to have an energy pay-back rime of around 1.5 year (1 year wit h heat recovery) and to save during their lifetime more than 20 times the amount of CO2 emitted daring their manufacturing (34 times heat re covery). (C) 1998 John Wiley & Sons, Ltd.