How do the environmental impacts of perovskite solar cells compare to those of silicon solar cells

The environmental impacts of perovskite solar cells (PSCs) differ from those of traditional silicon solar cells in several important ways, with both advantages and concerns.

Environmental Advantages of Perovskite Solar Cells Compared to Silicon

• Lower Carbon Footprint and Energy Payback Time: Perovskite solar cells have significantly lower carbon footprints and shorter energy payback periods than silicon solar cells. Manufacturing silicon panels requires intense heat to purify silicon, resulting in higher CO2 emissions. In contrast, perovskite cells can be made by low-temperature, solution-based processes such as screen printing, which are less energy-intensive and cheaper. For example, the energy payback period for silicon panels is about 1.52 years, while perovskite-perovskite tandem cells have a payback period as short as 0.35 years (about four months).
• Potential for Higher Efficiency and Reduced Environmental Impact Over Lifespan: Perovskite-silicon tandem solar cells achieve higher efficiencies (above 29%) than silicon alone, and despite additional manufacturing steps, they can have 6% to 18% less overall environmental impact over a 25-year lifetime due to higher energy output offsetting production impacts. The largest environmental impacts in tandem modules stem from silicon wafer production, not the perovskite layer itself.
• Lower Manufacturing Costs with Reduced Resource Use: Single-junction perovskite modules can be manufactured at costs significantly below those of crystalline silicon modules, which might reduce resource use and associated environmental impacts.

Environmental and Health Concerns Specific to Perovskite Solar Cells

• Lead Toxicity and Potential Environmental Release: A key environmental concern for PSCs is the presence of lead in most high-performance perovskite materials. The lead is in a soluble form that can leach into the environment, particularly if the solar modules break or degrade, releasing lead iodide which is water soluble and toxic. Lead present in PSCs can increase soil lead concentrations if not managed properly.
• Degradation and Stability Issues: Perovskite materials are susceptible to degradation from moisture, oxygen, and heat, which not only lowers their operational lifetime but also increases the potential for toxic lead release into the environment. Research efforts are underway to improve encapsulation and stability to mitigate this risk.
• End-of-Life Management and Recycling Challenges: Proper recycling and end-of-life management are essential to prevent environmental contamination from lead and other heavy metals in PSCs. Innovative recycling methods are being developed to recover valuable materials like lead and silver, aiming to create a circular economy that reduces environmental impacts.

Comparative Summary Table

Overall Assessment

While PSCs offer environmental benefits in terms of reduced carbon footprint, energy use, and manufacturing cost compared to silicon solar cells, their lead content presents significant environmental and health concerns that require careful management through improved stability, encapsulation, and recycling strategies. The environmental impacts of PSC technology can be lower than silicon when considering lifetime energy generation, but addressing the toxicity and disposal challenges of lead is crucial for sustainable commercialization.

In contrast, silicon solar cells are more mature with well-understood environmental profiles and recycling systems but carry higher embodied energy and carbon emissions due to their manufacturing processes.

Thus, perovskite solar cells represent a promising, greener solar technology provided that advances in lead management and durability are successfully implemented.