Silver scarcity need not trouble the PV industry, according to the authors of a paper on the topic, as long as efforts to reduce the metal's content in solar panels continue apace.
“The majority of them had the feeling this would not become an issue in the future,” University of Reading researcher Samuele Lo Piano told pv magazine.
Academics from Reading University, in the U.K., as well as Spain's Universitat Oberta de Catalunya and the University of Bergen, in Norway, compiled estimates of projected silver use trends from peers and several industry experts for the research. “We have tried to build scenarios on the basis of the quantitative estimates they provided us with,” added Lo Piano.
Asked how silver prices which are currently on the rise may have an impact on the PV industry, Lo Piano conceded they can be a good proxy during relative scarcity. “They cannot be considered, however, good proxies in a regime of absolute scarcity where the biophysical limits of an available commodity are close to being reached,” he explained. “In those settings … any market mechanism is bound to fail.”
Market agents can effectively intervene by triggering further efforts in exploration and technological solutions in an under-supply regime characterized by higher prices, he added. In these settings, companies would be motivated to improve the recovery conditions as well as to explore fields previously considered non-economically viable. “Conversely, any excess in supply would drive the opposite mechanism by lowering the commodity price and with it mining companies' efforts toward the exploration of new areas,” he stated. “However, market mechanisms are ineffective to perform any balancing function when the absolute physical limits are approaching.”
Lo Piano also explained that, when accounting for the possible overshooting of silver natural budget, the price of silver would act as a mere oscillatory mechanism alongside the overall trajectory toward the limit.
In the study, which was published in Frontiers Energy Research, Lo Piano and his fellow scientists stressed that most of the experts that participated in their survey agreed on the fact that, if a sudden rise in silver prices materializes, the industry could rapidly implement options to completely move away from silver use. “However, the pending issue remains at what pace this could take place,” the research group stated, adding that only one expert was convinced that silver availability may represent an issue for future PV deployment.
The paper highlighted that important research such as the 2011 version of the International Technology Roadmap for Photovoltaic (ITRPV) had forecast that silver would be completely replaced by copper in 2015. “However, this goal has been systematically moved forward in time and technological developments do not seem to promise a rapid and full silver replacement,” the report notes. During the past decade, the PV industry has reduced silver use but only for the rear contact of the cells with partial substitution with aluminum, and for the front side silver remains an unsolved issue, although copper-nickel alloys for the frontal contact metallization are considered a promising solution.
“Some of the engaged academics and experts from the industry that produced a quantitative estimate in the context of the study endorsed the estimates elaborated in the ITRPV,” Lo Piano explained. “Others assessed that silver would not be required anymore for the contact metallization of PV cells by the year 2050, or for a maximum of 20 mg silver per cell maximum.” The group of scientists quantified the yearly decrease in silver use for contact metalization in the range of 4 to 7%.
The authors of the study calculated the amount of yearly silver demand for the PV industry with a theoretical model that considered the amount of silver needed for silver pastes, the total production capacity of crystalline silicon modules, the increase in efficiency in crystalline solar cells, and silver demand in non-PV applications.
The 49 experts that participated in the study, which included 30 PV contact-metallization experts, 15 energy international agencies, and four silver-related consultancies, were asked to provide an estimation for the three parameters in the year 2050 and the speed at which future advances in solar cell metallization would be achieved.
“Several of the parameters have been randomized: rather than producing a single deterministic value, a range of possibilities has been evaluated,” the scientists explained. “To the best of our knowledge, it is the first time this type of approach is carried out in the assessment of the potentiality of silver constraint to a large scale solar photovoltaics development.”
The analysis conducted with the model suggests that the use of silver in the solar industry should proceed at a “meaningful pace,” if ambitious PV deployments targets need to be reached.
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