Solar panels have become popular as the demand for renewable energy has grown. Silver plays a vital role in producing solar power, with the average panel containing about 20 grams of silver and utilizing between 3.2 to 8 grams per square meter.
How is Silver Used in Solar Panels?
Silver is essential for solar energy. It is crucial for manufacturing photovoltaic (PV) solar panels because of its high electrical conductivity. Its primary application in solar cells is as a silver paste, which is applied to silicon wafers. This paste forms fine grid-like patterns known as “fingers” and “busbars” on the surface of the surface of solar cells. The conductive lines of these fingers and busbars help collect and transport electrons generated when sunlight hits the silicon, creating an electric current.
How Solar Panels Are Made
There are several steps to produce a solar panel:
Silicon Purification: Silicon is purified by heating quartz sand at high temperatures until it melts. This process removes impurities, leaving pure silicon, an essential component for producing efficient solar cells because it captures sunlight most effectively.
Wafer Processing: After the silicon is purified, it is sliced into thin pieces called wafers. The wafers are treated with chemicals like phosphorous and boron to craft two layers: a positive layer and a negative layer. The positive-negative junction is important as it imbues the silicon wafer with the ability to generate electricity when it is exposed to sunlight.
After the silicon wafers are produced, a silver paste made from silver particles is applied to the silicon wafer by means of a screen printing process. This process enables the silver paste to adhere to the wafer.
Solar Cell Creation: The treated silicon wafers are assembled into solar cells. When these cells encounter sunlight, energy from the sun excites electrons, generating a current.
Cell Interconnection: After the solar cells are produced, they are connected with thin silver or copper wire, which is soldered onto the cells in a grid pattern. This helps direct the current from one cell to the next. At this stage, the solar panel is complete, but there is still one step left before the panel is used.
Encapsulation and Framing: The solar cell is covered in a layer of ethylene-vinyl acetate (EVA), which binds the panel’s components in place. After applying the EVA, a sheet of tempered glass is placed over it. The final panel is framed with aluminum to provide structural support and facilitate easy mounting.
Glass is the largest component in a solar panel by mass, accounting for about 97% of a solar panel’s weight. It protects the solar cells and regulates heat and humidity within the panel. The combination of silicon, glass, aluminum, and other materials like plastic backsheets and EVA glue, creates a durable and efficient solar panel.
The Growing Demand for Silver in Solar Technology
A booming solar industry is driving a surge in the demand for silver to make photovoltaic (PV) panels. Global investment in solar PV manufacturing more than doubled in 2023, reaching about $80 billion and accounting for close to 40% of global investment in clean-technology manufacturing. Demand for silver from solar PV panel manufacturers is forecast to increase by almost 170% by 2030, potentially consuming around 20% of total silver demand.
In 2023 alone, photovoltaics consumed 142 million ounces of silver, representing 13.8% of total silver usage worldwide, up from nearly 5% in 2014. Despite this growing demand, the supply of silver has not kept pace, leading to increased prices and concerns about future availability.
Broader Implications of Silver Use in Solar Technology
Silver’s unique properties make it difficult to replace in solar technology. Its electric conductivity and efficiency are unmatched by most other metals, cementing its role as a critical component for renewable energy. The reliance on silver for silver cells poses challenges like supply constraints and cost fluctuations in the silver price. As the renewable energy industry grows, balancing the use of silver with the need for cost-effective and sustainable solutions will be crucial.
