Researchers at the University of New South Wales (UNSW), Sydney, have found that the current rate of reduction in silver consumption is insufficient to avoid the rising demand from the photovoltaic industry and requires increased investment to develop “silver-lean” photovoltaic technologies.

The team’s study titled, “The silver learning curve for photovoltaics and projected silver demand for net-zero emissions by 2050,” examined the impact of different PV technology pathways on silver demand.

The study reveals that the transition to high-efficiency technologies including TOPCon could greatly increase silver demand, posing both price and supply risks.

Use of Silver in Solar Cells

Solar cells typically use silver to conduct the electric charge out of the cell and into the system. Therefore, each cell when produced requires a few milligrams of silver.

But the problem arises when this adds up and with the rapidly growing solar industry much of the world’s known silver reserves are falling under threat of getting exhausted by 2050 or even earlier, the researchers noted.

Cell makers are keen on cutting the consumption of the metal, owing to the additional setback of heavy costs, as silver is one of the most expensive materials used in the process of manufacturing. The study finds reduction efforts need to ramp up significantly more to avoid a supply problem in the near future.

Particularly with the introduction of new n-type technologies, consumption is only increasing as these technologies require more silver than the Passivated Emitter and Rear Contact (PERC) cells which currently represent more than 80% of the market today.

Measures to Reduce Consumption

The team of researchers said the practice of copper plating represents a promising opportunity to accelerate the reduction of silver usage by the photovoltaic industry.

Over the longer term, the recycling of older solar modules could provide a significant source of silver.

Investment in research will be crucial in this regard, and it may still be several decades before the volume of photovoltaic waste processed is enough to account for more than a marginal contribution of new silver, the study said.

The team also warned against relying on the possibility of increased silver production, noting that the most accessible silver resources have already been mined. In this case, opening up new mines will likely mean digging deeper or processing lower-quality ores — all of which leads to increased energy consumption.

In December 2022, scientists at EMPA, Swiss Laboratories for Material Science & Technology, developed a low-temperature technique using silver to produce a bifacial perovskite-CIGS (copper indium gallium selenide) tandem solar cell, wherein the front side of the cell achieved record efficiency of 19.8% and the rear side displayed 10.9% efficiency.

In the same month, engineers at the Massachusetts Institute of Technology claimed to have developed an ultralight fabric solar cell that can turn any surface into a power source.