A Roadmap to the Second life of Photovoltaic Modules

Abstract

Two words that could epitomize the focal point of today’s society are ”Energy Transition” and ”Sustainability”. The PV systems are at the forefront of this energy transition. In PV systems, first-generation Si-based PV modules are the market leaders with a market share of 92.5% in 2020. However, sustainability concerns have emerged in recent years regarding the module technology’s post-initial lifespan. In order to make solar panels truly sustainable, it is also important to focus on what happens to these solar panels at the end of their initial intended use. The aim of this thesis is to focus on enhancing the sustainability of the existing PV system by investigating strategies to prolong the lifespan of PV modules through the concept of second life. To accomplish this, the thesis investigates the boundary conditions (the price of the refurbished module) for an economically feasible second use of PV. This research is crucial, particularly given the projected increase in cumulative installed capacity from 1 TWp in 2022 to 5.2 TWp by 2030, in order to meet the Paris Climate Agreement target of limiting global warming to below 1.5°C. To propose a new market structure, it becomes important to understand the existing policies and practices. Overarching policies in the EU, such as the Waste from Electrical and Electronic Equipment (WEEE) directive sets out the targets for collection, preparation for reuse and recycling, and recovery targets for waste generated from EEE including PV modules. Glass and aluminum are the components of the PV module that are recycled. They make up close to 85% of the weight of a PV module and represent only 35% of the total value of the components in a module. Most of the recycling today is
downcycling, meaning that not even 35% is completely recovered. The remaining materials and sometimes the entire module is dumped in a landfill at e1 per module. Recycling these panels can cost between €15 to €30 per panel and post recycling a minimum value of €6.6 and a maximum of €21 can be derived from the recovered materials. However, these materials cannot be directly utilized to manufacture PV panels without further processing. The thesis estimates the quantity of materials in PV systems, such as silver, copper, silicon, glass, and aluminum. This estimation includes the weight of each material within PV modules, as well as the monetary value associated with these materials. In the year 2030, about €86 billion and €58 billion worth of silicon and silver, respectively, are contained in the installed PV panels. If the prevalent EoL processes are followed, these materials will be unaccounted for at the end of their lifetime. All processes must be economically viable and operate within well-established financial boundaries. In this study, the concept of the Levelized Cost of Electricity (LCOE) is utilized as a standardized metric for comparing a new PV module versus a refurbished module and setting up boundary conditions. To emulate the market, two scenarios are considered. On the one hand, the first scenario considers the entire system cost, including the second-hand PV module, Balance of Plant (BoP), and soft costs. In this scenario, a minimum second lifetime of 23 years ensures a positive cash flow for the manufacturers/suppliers. On the other hand, the second scenario considers the placement of a second-hand module into an existing system (eliminating the need for additional BoP and soft costs) and shows that no minimum second life of the panel is needed to ensure a cash inflow for the manufacturers/suppliers. The effect of subsidies and policies on LCOE are also analyzed utilizing discount rates. In general, the higher the discount rate, the higher the resultant LCOE. Finally, a market structure that utilizes the concept of a Product Service System (PSS) and aims to facilitate the utilization of second-life PV modules along with a proposal for the positioning of a Product Service System Provider (PSSP) is presented. Integration of the PSSP into the existing market structure is proposed in a stage-wise manner, utilizing the distribution system operator (DSO) for effective implementation. To achieve this integration, two strategies are recommended, one based on the size and capacity of the installed systems and the other based on geographical boundaries. Additionally, a brief overview of PV subscribe, which is a business model that stimulates the second-life market, is provided.