Deciphering the uncertainties in life cycle energy and environmental analysis of organic photovoltaics

Organic photovoltaic (OPV) technologies are rapidly emerging as a viable alternative for traditional silicon and thin film technologies. OPVs are projected to be comparatively inexpensive and have a low energy payback time (EPBT) with lower levels of anthropogenic emissions during their lifetime. In this paper, we have analyzed the life cycle environmental impacts and EPBT of a scalable OPV module in the three cities Chicago, New York and San Francisco, for the current, near-term future and long-term future scenarios. Instead of using the deterministic or 'single point estimate' method, we employed a probabilistic approach by applying an uncertainty analysis to each of these scenarios using the Monte Carlo simulation method, and thereby quantifying the uncertainty and risk associated with each scenario. By comparing the proposed OPV technology with four typical silicon-based and thin-film photovoltaics in the aspects of EPBT and greenhouse gas (GHG) emissions, we demonstrate the great potential of OPVs in environmental sustainability. The probabilistic approach displayed a wide distribution for the EPBT and CO2 emission factor values, rather than squeezing around a single value. This demonstrated the insufficiency of deterministic analysis, which would give a false impression of certainty in the outcomes.