Researchers at the National Energy Laboratory (NREL) have recently conducted the first global assessment in the most promising approaches to recycling management for solar photovoltaic (PV) modules.
Traditional PV modules have a life span of 30 years. Currently, there is no set plan for how to manage the disposal of these modules. The volume of modules no longer in use will go up to 80 million metric tons by 2050. Additionally, the nature of the waste also poses various challenges. PV modules are made up of precious, valuable, and some toxic materials. There is no standard method for recycling the valuable ones and dispose of the toxic ones.
Several articles review individual options for PV recycling, but no one has performed a global assessment of all PV recycling efforts to identify the most promising approaches. Garvin Heath, a senior scientist at NREL, explained that PV is a significant part of the energy transition. Becoming good stewards of these materials and developing a circular economy for PV modules is necessary.
The team focused on the recycling of crystalline silicon, a material used in more than 90% of installed PV systems in the purest form. It accounts for about half of the energy, carbon emissions, and cost to produce PV modules, but only a small portion of their mall.
According to the experts, it takes a lot of investment to make silicon pure. For a PV module, these silicon cells are sealed up in a weatherproof package where they are touching other materials, and wait 20 to 30 years—all the while, PV technology is improving.
The research team found some countries have PV recycling regulations on point, while others are just beginning to consider various solutions. Currently, only one crystalline silicon PV-dedicated recycling facility exists due to the limited amount of waste being produced today.
Based on their research, the team recommends research and development to reduce recycling costs and environmental impacts while increasing material recovery. They suggest focusing on the high-value silicon versus whole silicon wafers. The intact silicon wafers are somewhat achievable, but they often crack and would not likely meet today’s standards to enable direct reuse. To recover high-value silicon, the team highlights the need for research and development of silicon purification processes.
They also emphasize that the environmental and economic impacts of recycling these particles should be explored using technological and financial analyses and life-cycle assessments. Finally, the team explained that finding ways to avoid waste is an integral part of the equation, including making solar panels last longer, using material that is effective, and producing electricity more efficiently.
The team states that research and development are needed because the accumulation of waste will cause trouble later. Much like the growth of PV installations, it will seem to move slowly and then rapidly increase. By the time there’s enough waste to open a facility dedicated to PV, the researchers will develop a proper process. If successful, these findings could contribute to the development of the PV circular economy.