Energy Return on Energy Invested (EROI) is a metric used to quantify the amount of energy produced by an energy source system compared to the amount of energy needed to build and operate the system. EROI is a unitless ratio of the energy produced for society to the energy required to make that energy. An energy source with an EROI of less than 1:1 is not considered viable. Thin film PV technologies provide the greatest return on energy invested as they require less energy during manufacturing.
Life-Cycle GHG Emissions of Different Energy Technologies
Energy Return on Energy Invested (EROI)
Reuse and Recycling for a Circular Economy
Thin film PV technologies contribute to a circular economy by providing a secondary use for mining byproducts that would otherwise be disposed of. Cadmium, gallium, germanium, indium, selenium, and tellurium are sourced as byproducts from the production of aluminum, zinc, lead, copper and coal. At the end of their 25+ useful lifetime, thin film PV modules can be recycled to recover glass and semiconductor metals for reuse in new thin film modules and glass products. With over 200GW of PV installed worldwide, proven high-value PV module recycling solutions are important for all solar technologies. In addition to PV Cycle, there are a number of innovative high-value thin film PV recycling initiatives operational worldwide that are helping to close the loop.
In 2014, Japan’s New Energy and Industrial Technology Development Organization (NEDO) developed an innovative PV recycling technology in 2014 which separates and processes various types of modules (crystalline-silicon, thin-film silicon, and CIS). The technology is currently in its pilot phase with a maximum annual throughput of around 12 MW for crystalline Si panels and 7 MW for CIS panels.
The European Union’s Seventh Programme for research, technological development and demonstration is funding the EU RE-CLAIM’s green technology recycling project. EU Reclaim is developing a high-value recycling plant pilot that can be applied in an industrial setting to contribute to a circular economy by recovering gallium, indium and valuable rare-earth elements used in PV technologies, solid-state lighting (SSL), and other electronic waste.