Raw Material Needs for the Large-Scale Deployment of Photovoltaics - Effects of Innovation-Driven Roadmaps on Material constraints until 2050
The photovoltaic technological landscape is rapidly evolving. The current push to increasingly efficient solar cells is leading to the emergence of novel technologies such as heterojunction and multijunction with specific material requirements. In this paper, the metal and metalloid requirements for the global deployment of next-generation photovoltaics in the multi-terawatt range until 2050, in accordance with the Paris Climate Agreement, are assessed and compared for selected technology roadmaps. The potential for greater resource efficiency is highlighted. Both conventional and disruptive strategies such as frameless designs, substitution, alternative production processes offer substantial untapped potential for reducing material intensity. However, this is still insufficient to eliminate all supply risks identified based on a material demand-to-production comparison. In order of priority - gallium, indium, arsenic, bismuth and selenium - were found to be on short supply in all scenarios considered. They should be targeted by risk mitigation strategies from both demand and supply sides, or avoided altogether. Silicon supply, as a key enabler for photovoltaic, should also be closely monitored. The solar cell technologies are affected by these supply risks to varying degrees. Passivated and heterojunction cell designs without material shortages could be laid out within the scope of this paper. On the contrary, the multijunction concept could become unsustainable as early as 2030, when the gallium requirement for 20% market shares of multijunction exceeds its current supply potential. Overall, concerns regarding novel solar cell concepts call for stronger integration of sustainable material use considerations in technological development.