Silver Linings of Solar: Unraveling the Silver Learning Curve for PhotovoltaicsPosted on: 2023-05-02 14:02:07
The global push for net-zero emissions by 2050 has amplified the importance of renewable energy, particularly solar photovoltaics (PV). An interesting aspect of PV technology is its reliance on silver, a critical material in solar panels. In this blog post, we delve into the article "The silver learning curve for photovoltaics and projected silver demand for net-zero emissions by 2050" to discuss the connection between advancements in PV technology and silver consumption, as well as the implications for future silver demand.
The Silver Learning Curve:
The article explores the relationship between PV technology improvements and silver consumption. Silver, with its excellent electrical conductivity, is essential in solar panels to enhance energy efficiency. The term "silver learning curve" describes the trend of decreasing silver content in solar cells as PV technology progresses.
This learning curve was measured to have a rate of 20.3 ± 0.8%, indicating that silver consumption decreases by about 20% for every doubling of cumulative installed PV capacity. The learning curve is expected to have a significant impact on the silver demand for PV installations in the coming decades.
Technical Specifics of Silver in PV Cells:
Silver is predominantly used in solar cells as a conductive material in the form of silver paste, which forms the electrical contacts on the front and back of the solar cells. As PV technology has advanced, manufacturers have been able to reduce the amount of silver used per cell without compromising performance. This trend can be attributed to innovations such as thinner silver paste layers, more precise screen-printing techniques, and alternative conductive materials that partially replace silver in the paste.
Silver consumption in solar cells is largely determined by the choice of solar cell technology. The widely used p-type PERC cells consume 14.4-15.7 mg of silver per watt, while next-generation, high-efficiency n-type TOPCon and SHJ cells have higher silver requirements, consuming 20.4-26.0 mg/W and 30.3-37.4 mg/W, respectively (see Figure below). As the solar industry continues to grow, the demand for silver is expected to increase, particularly with the adoption of silver-intensive n-type technologies.
Projected Silver Demand for Net-Zero Emissions by 2050:
To assess future silver demand, the authors examined various scenarios, taking into account the expected growth in PV installations and the silver learning curve. They found that the demand for silver in PV manufacturing could range from 2.2 to 4.5 million metric tons by 2050, depending on the adoption rate of PV technology and the rate of silver consumption reduction in solar cells.
Based on the silver learning curve, the article projects that the cumulative installed capacity of photovoltaics could increase from 1 TW before the end of 2022 to 15-60 TW by 2050. This growth would create a significant silver demand risk. However, the learning curve suggests that advancements in PV technology could help reduce the silver consumption per solar cell, thereby reducing the overall demand for silver. As mentioned earlier, the current reduction in silver consumption might not be sufficient to offset the growing demand from the photovoltaic sector. Therefore, it is essential to continue investing in silver-lean PV technologies to meet the growing demand for silver in the solar industry without exhausting the world's silver reserves.
To avoid any decrease in the silver LR of the PV industry as a whole, any major deployment of silver-intensive screen-printed n-type TOPCon and SHJ technologies must be balanced by a substantial deployment of silver-free or silver-lean TOPCon and SHJ solar cells. For screen-printed TOPCon cells, silver consumption could be greatly reduced by replacing the silver/Al p-type contact by a pure Al contact, similar to that of PERC.
Challenges and Opportunities:
The study highlights the need for continued innovation in PV technology to further reduce silver consumption without sacrificing efficiency or performance. Additionally, it underscores the importance of investing in silver recycling and exploring alternative materials for solar cell manufacturing to meet the growing demand for PV installations.
In conclusion, the projected silver demand for net-zero emissions by 2050 will be heavily influenced by the silver learning curve and advancements in PV technology. By understanding the relationship between the learning curve and silver consumption, stakeholders can make informed decisions about the development and adoption of silver-lean photovoltaic technologies but also need to be aware that metrics show that even with a learning curve, we are likely to run up against supply issues as the economy is further scaled.