How much does recycling uncertainty affect the environmental trade-off?
The choice of how to model recycling in life-cycle assessments can change the estimated climate impact of perovskite-silicon tandem modules by roughly 30%. One study tested six different recycling modeling approaches and found that the carbon footprint ranged from 45 to 59 kg CO2-equivalent per square meter of module [1]. This means that depending on whether you assume the module will be recycled efficiently or not, the environmental cost could be significantly higher or lower. The authors recommend using the Circular Footprint Formula as a middle-ground approach, but also stress that sensitivity analysis is needed to check results [1]. For a typical reader, this means the trade-offs are not fixed—they depend heavily on future recycling infrastructure, which is still uncertain for this emerging technology.
What specific materials or design choices drive the environmental impact?
At the lab scale, the perovskite cell itself is responsible for about three-quarters of the total environmental impact of a perovskite-silicon tandem solar flow battery system, while the frame accounts for the rest [3]. A key culprit is the use of gold as a back electrode—switching to a different material could substantially reduce the cell's footprint [3]. The same study also notes that as the system scales up, the relative impact of the frame will shrink, but the importance of the electrolytes (used for energy storage) will grow [3]. This suggests that current estimates may underestimate trade-offs if they assume lab-scale material choices (like gold) will persist in commercial production.
Can the higher efficiency of tandem cells offset these environmental costs?
Yes, the higher efficiency of perovskite-silicon tandems is a major environmental advantage that can compensate for some of the trade-offs. One study notes that tandem modules have already reached 26% efficiency and are expected to exceed 30% by 2030, compared to around 20-22% for standard silicon panels [2]. This means you need fewer panels and less land to generate the same amount of electricity, which reduces the overall environmental impact per kilowatt-hour. However, the same study emphasizes that the long-term stability of perovskite layers has been a weakness, and pairing them with silicon in a tandem configuration is a way to combine stability with high efficiency [2]. So the trade-off is not just about materials and recycling—it's also about whether the efficiency gains are large enough to make the extra complexity worthwhile.
About These Sources
This answer is built on 3 studies (2 peer-reviewed, 1 preprint) — published from 2021 to 2024, 1 from 2024 or later — selected as the most relevant from 3 studies that passed quality screening, drawn from 48 papers retrieved from a database of over 500 million.
Sources used in this answer
Modelling recycling for the life cycle assessment of perovskite/silicon tandem modules
Modeling recycling for perovskite-silicon tandem modules using six different approaches showed that the climate change impact varies from 45 to 59 kg CO2-eq/m², a non-negligible 30% range, highlighting that end-of-life assumptions strongly affect environmental trade-offs.
Comparative and Prospective LCA of Perovskite-Silicon Tandem PV Modules
A comparative and prospective life-cycle assessment found that perovskite-silicon tandem modules have reached 26% efficiency and are expected to exceed 30% by 2030, offering a significant efficiency advantage over standard silicon, but stability remains a key concern.
Life Cycle Assessment of Perovskite/Silicon Tandem Solar Cells Coupled with Solar Flow Battery Systems
For a lab-scale perovskite-silicon tandem solar flow battery, the perovskite cell causes 75% of the environmental impact, largely due to the gold back electrode, while the frame accounts for the rest; switching to a different electrode material could reduce the impact.