Dutch researchers used dynamic models to reveal the demand for silicon-based PV materials used in a wide range of silicon PV technologies, including perovskite-silicon tandem and back-contact modules. The model included calculating the impact of advances in module efficiency and material intensity, as well as closed-loop circular recycling.
A research group in the Netherlands used dynamic models to calculate the demand for silicon-based PV materials in future scenarios that include the deployment of perovskite-silicon tandem and back-contact technologies, implying that the goals of a net-zero greenhouse gas emissions are achieved. It included calculations with module efficiency and progress in material intensity.
Looking at the exponential growth of solar and silicon-based PV modules and the potential demand for materials, the group asked how much impact PV technology choices could have on demand for materials such as indium and silver.
To find the answers, the team used a dynamic material flow analysis (dMFA) model developed specifically for silicon-based PV. The dMFA methodology they used captured future annual dynamics in PV deployment capacity, module efficiency, material compositions, and market shares for different PV technologies.
“The most interesting aspect of the study is the model itself, which includes annual dynamics in PV deployment capacity, module efficiency, material compositions and market shares for different PV technologies until 2050,” said the lead author of the study, Chengjian Xu. pv magazine.
In its modeling, the group identified potential shortages of silver and indium, but also that technological advances, such as improved PV module efficiency and reduced material mass per module area, are an opportunity to influence demand. For example, annual demand for PV module materials, such as silicon, aluminum, silver and other materials, could be reduced by 46%, 35%, 30% and 13%, respectively, compared to scenarios without such improvements. In addition, closed-loop recycling can reduce demand for materials by 10% to 30%.
The model included a range of silicon PV technologies: aluminum back surface field (Al-BSF), passivated emitter and back contact (PERC), tunnel oxide passivated contact (TOPCon), silicon heterojunctions (SHJ), interdigitated back contact (IBC), and perovskite-silicon tandem, in four-terminal (4T) and two-terminal (2T) tandem variations.
“This study provides a more comprehensive technology roadmap compared to existing ones, which often focus on a limited number of technologies and overlook the perovskite-silicon tandem,” the researchers said.
The efficiency constraints were set at 20% for Al-BSF, 24% for PERC, 26% for both TOPCon and SHJ, 26.5% for IBC and 39% for perovskite-silicon tandem modules. Higher efficiency was taken into account for double-sided PV modules.
Historical data on PV deployment capacity from 2000 to 2022 comes from the International Renewable Energy Agency (IRENA). Two future scenarios for PV deployment were used: one from the International Energy Agency (IEA), representing the conservative PV scenario, and an optimistic scenario, based on 2021 forecasts by another research team. Both aimed to achieve net-zero emissions by 2050.
For the technology selection, the team used data from the International Technology Roadmap for Photovoltaic (ITRPV) up to 2030 and further extrapolated it to 2050 by incorporating estimates from other sources.
The results for the period 2022 to 2050 indicated that demand for indium could increase by between 38 and 286 times the status quo, and for silver by 4 to 27 times, while demand for other materials could increase by a factor of 2 to 20 could increase depending on the PV deployment scenario. .
“The demand for indium and silver is mainly influenced by the choice of PV technology,” the researchers said. Cumulative indium demand over the period 2022-2050 could range from 0 kt in a 100% PERC and TOPCon scenario to 209 kt in a 100% perovskite-silicon tandem PV with four terminals. Cumulative silver demand over the same period could range from 144 kt in a 100% PERC PV scenario to 1121 kt with 100% silicon heterojunction PV penetration.
They also highlighted that improvements in material intensity could reduce annual demand for PV module materials by 46% for silicon, 35% for aluminum, 30% for silver and 13% for other materials, compared to scenarios without such improvements.
Moreover, they said: “A promising approach to mitigate the increasing demand for primary materials is closed-loop recycling. By implementing efficient PV collection and recycling processes, cumulative primary material demand could be reduced by 10% to 30% between 2022 and 2050.”
The research is described in detail in “Future demand for materials for global silicon-based PV modules under the net-zero emissions target to 2050”, published by Resources, conservation and recycling. The participants in the study came from Delft University of Technology and Leiden University.
Looking ahead, Xu said there are plans to update the technology roadmap data and further expand the scope of research to include the relevant balance of material demand for system components in future scenarios.
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