A comparative human health, ecotoxicity, and product environmental assessment on the production of organic and silicon solar cells

Abstract

A life cycle assessment case study involving organic photovoltaic technology using phenyl-C 61 -butyric acid methyl ester and poly(3-hexylthiophene) is presented. Although solar technology converts freely available solar radiation into more useful forms of energy, potential environmental impacts can occur during the life cycle of the product. A cradle-to-gate life cycle assessment is completed, comparing organic solar cells with traditional silicon-based cells across 18 multiple criteria. The functional unit is defined as the production of 1 watt-peak of electricity produced. The inventory is based on prospective organic solar cell technology and two traditional silicon technologies. The results demonstrate that from a life cycle perspective, organic solar cells can outperform conventional silicon solar cells with impacts reduced by 93%. The energy payback time for the default organic photovoltaic cell was 0.21 years (75 days) compared with multicrystalline silicon and amorphous silicon's 2.7 and 2.2 years, respectively. The minimum required lifetime of the organic cells, so that their impacts were no worse than amorphous silicon's over 25 years, was measured between 1.2 and 8.9 years. Results of the sensitivity analysis demonstrate that consideration of manufacturing routes (e.g., fullerene or solar cell production) can be targeted using life cycle assessment for further improvements in the environmental, human health, and ecotoxicity profile of organic solar cells.

Green and Clean: Reviewing the Justification of Claims for Nanomaterials from a Sustainability Point of View

“…In the solar sector, the deposition process, which is the synthesis of nanomaterials in layers, has been recorded in most reviewed studies, except of the studies of Roes et al [17] and Tsang et al [20], as one of the most important contributors for both primary energy consumption and climate change impact. Different deposition methods have been included in the reviewed studies.…”

“…This indicates that results were more promising for polymer PVs on flexible substrate. In the case of Tsang et al [20], the minimum required lifetime for the OPVs to compete a-Si PVs in terms of climate change potential is 4.8 years. At the time the study was performed the maximum lifetime of OPVs was 7 years.…”

“…In the studies of Roes et al [17] and Tsang et al [20] the performance of polymer PVs and organic PVs are on a per watt-peak basis. In the case of Roes et al [17], the reason that watt-peak has been chosen as a functional unit is that at the time the study was performed, the lifetime of polymer PVs was much lower compared to multicrystalline silicon PVs.…”

“…Other impact categories have been analyzed in five of the reviewed studies in the solar sector [17,18,20,21,24]. The study from Zhang et al [24] calculates the environmental impacts of TNT perovskite solar cells from cradle to gate, for different impact categories, but the comparison among other type of solar cell technologies is based only on greenhouse gas emissions.…”

“…In terms of carbon emissions, three studies have concluded that nano-based photovoltaic cells perform better to alternatives. These studies are from Roes et al [17], Sengul and Theis [18] and Tsang et al [20], for the environmental assessment of glass/flexible polymer photovoltaics, quantum dot photovoltaics and organic photovoltaics respectively. Greijer et al [19] found that nanocrystalline dye sensitized solar cells have comparable emissions as amorphous silicon solar cells.…”