Citation: Tan, J.; Jia, S.; Ramakrishna, S. End-of-Life Photovoltaic Modules. Energies 2022, 15, 5113. https:// doi.org/10.3390/en15145113 Academic Editor: Gianpiero Colangelo Received: 14 June 2022 Accepted: 12 July 2022 Published: 13 July 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Review End-of-Life Photovoltaic Modules Jovan Tan 1,2, * ,† , Shuyue Jia 1,† and Seeram Ramakrishna 1,2 1 Center for Nanotechnology and Sustainability, Department of Mechanical Engineering, National University of Singapore, Singapore 119077, Singapore; shuyue@u.nus.edu (S.J.); seeram@nus.edu.sg (S.R.) 2 Solar Energy Research Institute of Singapore, Solar Energy System Cluster, Singapore 117574, Singapore * Correspondence: jovan@u.nus.edu † These authors contributed equally to this work. Abstract: More than 78 million tons of photovoltaic modules (PVMs) will reach their end of life (EOL) by 2050. If they are not responsibly managed, they can (a) pollute our terrestrial ecosystem, (b) indirectly encourage continuous mining and extraction of Earth’s finite resources, and (c) diminish the net environmental benefit of harvesting solar energy. Conversely, successfully recovering them could reduce resource extraction and waste and generate sufficient economic return and value to finance the production of another 2 billion PVMs by 2050. Therefore, EOL PVMs must participate in the circular economy, and business and political leaders are actively devising strategies to enable their participation. This article aims to facilitate and expedite their efforts by comprehensively reviewing and presenting the latest progress and developments in EOL PVM recovery methods and processes. It also identifies and thoroughly discusses several interrelated observations that impede or accelerate their efforts. Overall, our approach to this article differs but synergistically complements and builds upon existing life cycle assessment-based (LCA-based) contributions. Keywords: life cycle; circular economy; circularity; end-of-life; solar energy; photovoltaics; energy decarbonization; energy systems; photovoltaic modules; sustainability 1. Introduction Renewable energy will be the future as the push for energy decarbonization accel- erates. These energy sources are virtually inexhaustible and replenish naturally. They also do not pollute the air or emit harmful greenhouse gases. The total renewable energy produced worldwide grew by more than 75% in the preceding decade, from 4196.94 to 7443.81 Terawatt-hours (TWh) [1]. The International Energy Agency [2] projects that re- newable energy systems will account for almost 95% of the increase in the global power capacity over the next 5 years. Such accelerated growth is expected, with a more significant and concerted push towards net-zero emissions. By 2050, renewable energy systems will likely replace fossil fuel-based energy systems as the dominant energy source [3,4]. 1.1. Current State and Prospects of Solar Energy Systems Among all, harvesting solar energy is one of the fastest-growing avenues and most favored [5]. Solar energy systems accounted for over half of all renewable power expansion in 2021 [2]. It experienced the most growth in the preceding decade among all renewable energy systems. Its global output grew at a 38.8% compounded average growth rate, implying that annual solar power generation doubled every few years. If solar energy systems continued to grow at this rate, they would become the most significant contributor to power generation growth [1,2,4,6]. Solar energy is one of the safest forms of energy on Earth [7]. Sunlight, the richest and most abundant resource that reaches all parts of Earth’s surface [8], can be converted into electricity using photovoltaics, solar heating and cooling, and concentrating solar power [9]. Energies 2022, 15, 5113. https://doi.org/10.3390/en15145113 https://www.mdpi.com/journal/energies