First results regarding the environmental impact of perovskite/silicon tandem PV modules

CHEOPS member SmartGreenScans has recently completed an initial study evaluating the life-cycle environmental impact of perovskite/silicon tandem modules from Oxford PV. The results are positive regarding the impact of perovskite devices on global warming and energy demand.

Given their low cost and high power conversion efficiency, perovskite solar cells have gained attention in recent years. However, the use of this perovskite solar cell technology has also raised concerns about their environmental impact, notably due to the presence of lead.
SmartGreenScans, a CHEOPS partner specialising in Life-Cycle Assessment (LCA) of photovoltaic technologies, has conducted a preliminary study to assess the life-cycle environmental impact of the perovskite/silicon tandem modules to be commercialised by Oxford PV, another CHEOPS partner. The analysis covers all activities from “cradle” up to the factory “gate” where it is manufactured and assembled. This “cradle-to-gate analysis” is considered a partial product life-cycle.

The study takes into account the following:

  • Resource depletion, climate change, ozone depletion, cancer and non-cancer toxicity effects, particulate matter, ionising radiation, photochemical ozone formation, acidification, terrestrial eutrophication, freshwater ecotoxicity and land use. All were assessed through the ILCD2011 impact assessment method.
  • The Global Warming Potential (greenhouse gas effect) has been assessed with the IPCC2013 GWP100a method.
  • The Cumulative Energy Demand: the energy used throughout the life cycle of a good or a service including direct and indirect uses.

The results were as follows:

  • According to the ILCD2011 single scores, the highest impact for the tandem module originates from the monocrystalline silicon solar cell (43%). Other contributors are indium in the transparent conducting oxide (29%), metallization paste (11%), silver (5%) and aluminium frame (4%).
  • Emitted lead from the tandem module contributes only 0.27% or less to the total freshwater ecotoxicity, total cancer effects in human toxicity or total non-cancer human toxicity.
  • Regarding the Global Warming Potential of the tandem module, the dominant contribution comes from the monocrystalline silicon solar cell (73%). Lesser factors are electricity consumption (7%), glass (7%), aluminium frame (5%), and metallization paste (1%). The Cumulative Energy Demand has a similar ranking.

These preliminary results indicate that the primary impact on the use of resources, global warming and energy demand comes from the standard silicon device and not from the perovskite device.
This study is a first step towards a full “cradle-to-grave” LCA analysis which will also include the installation, operation, maintenance and end-of-life phases of the photovoltaic module.