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| Solar Recycling Plant. (Source: Image created by Chetan3105 on Gencraft) |
Solar energy has been the most promising renewable energy source and has a major contribution in gigawatts out of the total renewable energy sources combined. Sun is the major source of solar energy and all are aware of that, even though it's not new to know that "Photovoltaics Cell" or the simple term "Solar Panel" is used to generate electricity through solar energy conversion.
As per the International Energy Agency (IEA) "Renewable Energy Market Update - Outlook for 2023 and 2024" Report, the solar PV capacity rose by 35% from 2021. With the rising demand for the shift from conventional to unconventional sources of energy, it is critical to understand the methodology to dispose of the solar panel after completion of the service life.
There has been a controversy about whether it is economically feasible to dispose of the panel after the completion of operation life rather than going through the recycling process. If not recycled properly, it is even predicted that the world will end up with tonnes of solar waste. In this article, we will delve into understanding the current process of recycling solar panels, its impact on the environment, and its associated costs.
The Dilemma of Solar Panel Disposal
Economic Considerations:
Decommissioning Costs: Exploring the expenses associated with dismantling and disposing of solar panels. The decommissioning cost is unpredictable since it is based on the waste and recycling markets and the labor cost required. For instance, it will be cheaper to dismantle panels in South Asian countries compared to the developed nations.
However, anywhere the panel is disassembled, the items that need to be recycled are aluminum frames, copper wires, racking, battery backup systems, trackers, inverters, mountings, and any plastic or fiber materials involved in it. According to one of the blogs published by CommercialSolarGuy on "What to do with old solar panels", decommissioning 15000 panels, roughly it cost around USD 11.71, and if we consider increasing rates of inflation and labor costs it can go beyond the given cost.
Market Dynamics: Understanding the economic factors influencing the recycling market for solar panels. The major factor influencing the market is geographical location, but let us look at each point one by one:
- If the cost of extracting raw materials in a particular country is lower than recycling then this might discourage the recycling market from putting an effort.
- Since the solar energy market is booming and we might see an increase in the volume of decommissioned panels, it might create an opportunity to recycle rather than extract.
- If more cost-effective and efficient processes emerge for recycling solar panels then this might attract businesses and start-ups to engage in recycling activities.
- There are incentives, rebates, and subsidies to install panels similarly if the government introduced new regulations and policies on proper disposal and recycling then this might impact the recycling market in a good way.
- Another factor is waste management costs or landfill disposal fees. Increasing the landfill disposal cost along with stricter environmental regulations might make recycling a more economically feasible option.
- Well-established infrastructure and facilities play a crucial role by handling capacity in large volumes and reducing recycling costs.
- Introducing some responsibility programs for producers for end-of-life management of their products, this approach might lessen and shift the financial burden from the government to manufacturers.
- The most important and underrated factor is public awareness. This not only influences consumer choices but also emphasizes sustainable practices.
Environmental Impacts:
E-Waste Concerns: Addressing the environmental consequences of improper disposal. Since solar panels are categorized as electronic waste (e-waste) and involve materials that are challenging to recycle, improper disposal contributes to major problems.
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| Electronic Waste also known as E-Waste has become a global concern. (Source: Image created by Chetan3105 on Gencraft) |
Toxic Materials: Unveiling the potential environmental hazards related to certain materials used in solar panels.
- The solar panel often contains heavy metals like lead and cadmium, if not handled properly it may lead to health issues and if disposed of in a landfill then it can leach into soil and contaminate groundwater.
- During the manufacturing phase, fluorine compounds are used in some types of solar panels, and they can lead to pollution if disposed of carelessly.
- Chemical like Silicon Tetrachloride is utilized in the production of solar panels and if they come in contact with water after their end-of-life, the chemical will react with water to form corrosive hydrochloric acid which is hazardous.
- Another chemical used while manufacturing is Ethylene glycol and it has hazardous risks for humans, plants, and aquatic life.
Cost Dynamics of Solar Panel Disposal
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| General flowchart to recycle Si-PV Modules. (Source: Deng, Rong & Chang, Nathan & Ouyang, Zi & Chong, C.. (2019)) |
According to "A techno-economic review of silicon photovoltaic module recycling" research article by Dr. Rong Deng and her team, the above-shown flowchart was used to study the sequence of recycling the photovoltaic modules. There are four generalized methods used for recycling solar cells, with the most probable method being "Method A: Landfill".
Recycling vs. Landfill:
Please note that the data for recycling cost vs. landfill cost is referred from "A techno-economic review of silicon photovoltaic module recycling" research article and is based on the recycling cost and associated costs:
Table 1: Recycling cost for End-of-Life Si PV Module
Recycling Method | Cost Component | Low Value | Median Value | High Value | Assumptions/Notes |
|---|---|---|---|---|---|
| Glass Recycling | Processing Cost | -30% | Baseline | +30% | Assumes mature technology with ±30% uncertainty. |
| Mechanical Recycling | Factory Operational Cost | -40% | Baseline | +40% | Referenced study with a 25% reduction for economies of scale. |
| Thermal Recycling | Processing Cost | Baseline | Baseline | 2x Baseline | Assumed based on comparison with commercial scale mechanical recycling process. |
Table 2: Non-Processing Costs and Revenues
Recycling Method | Cost/Revenue Component | Low Value | Median Value | High Value | Assumptions/Notes |
|---|---|---|---|---|---|
| All Methods | Si Recovery Value | 30% Discount | Baseline | Equivalent to New Wafers | Assumes reuse in the industry; Thermal recycling assumes equivalent value to virgin new wafers. |
| All Methods | Landfill Disposal | $10/tonne | $150/tonne | $400/tonne | Current landfill levies in EU 28 countries; Some regions may forbid landfills, treated as an infinite cost. |
Notes:
- Table 1 and Table 2 exhibit range: low, median, and high values for each cost associated with all methods.
- The assumptions for the processing costs are established on uncertainty ranges with each recycling method.
- Silicon recovery value assumes distinct values grounded on the recovered silicon type and its variation in potential future markets.
- Landfill disposal cost variation is established on the country, its regulations, and potential penalties for illegal dumping.
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| Probability and Cost distribution for Si-PV Panels with options A-D. (Source: Deng, Rong & Chang, Nathan & Ouyang, Zi & Chong, C.. (2019)) |
Based on the Monte Carlo uncertainty analysis of the alternative recycling scenario (as shown in the graph above) studied in the research article, the cost associated with each scenario is tabulated in Table 3 below.
Table 3: Net Recycling Cost Summary for Four End-of-Life (EoL) Methods
Method | Low Value (USD/kg) | Median Value (USD/kg) | High Value (USD/kg) | Revenue Source | Key Observations |
|---|---|---|---|---|---|
| A (Landfill) | $10/tonne | $64/tonne | $407/tonne | None | Expected to be cheaper due to simplicity and accessibility; No revenue from recycling. |
| B (Baseline Recycling) | $279/tonne | $393/tonne | $573/tonne | Si Recovery | Recycling cost distributions overlap with landfill cost; Financial attractiveness under certain conditions. |
| C (Upcycling Method C) | $748/tonne | $922/tonne | $1153/tonne | Si Recovery, Other | Higher expected revenue, but higher processing costs result in a worse net cost than Method B. |
| D (Upcycling Method D) | $1034/tonne | $1200/tonne | $1420/tonne | Si Recovery, Other | Higher expected revenue, but even higher processing costs than Method C; Worse net cost than Method B. |
Global Regulations:
SEIA National PV Recycling Program: The Solar Energy Industries Association (SEIA) has initiated a member-based National PV Recycling Program, encouraging responsible EoL management of PV modules. The program aggregates services offered by recycling vendors and PV manufacturers, creating a network of cost-effective recyclers. This initiative is industry-driven and aims to establish environmentally sustainable practices.
Silicon Valley Toxics Coalition Solar Scorecard: The Solar Scorecard developed by the Silicon Valley Toxics Coalition (SVTC) serves as a voluntary industry standard promoting transparent environmental and social justice practices. It includes criteria related to EoL PV management practices, emphasizing extended producer responsibility (EPR) and green design.
NSF/ANSI 457 Sustainability Leadership Standard: The NSF/ANSI 457 standard establishes sustainable performance criteria and corporate metrics for PV modules and inverters. This industry-led standard encourages solar manufacturers to demonstrate compliance with sustainable practices, influencing EoL management decisions based on environmental and corporate performance.
SERI Responsible Recycling (R2) Standard: The SERI Responsible Recycling (R2) standard, revised in 2020, encourages environmentally sustainable electronics recycling practices. While not explicitly applicable to PV modules at present, efforts are underway to evaluate whether the standard should be adapted for PV panels. The industry-led initiative reflects a commitment to responsible EoL management.
Recycling Industry Operating Standards (RIOS): The Recycling Industry Operating Standard (RIOS) integrates ISO standards into a single management system, providing a systematic framework for recyclers to achieve environmentally sustainable performance objectives. The collaboration of R2 and RIOS in a combined standard further emphasizes industry-driven efforts to ensure safe and sustainable recycling practices.
e-Stewards Standard: The e-Stewards Standard, developed by the Basel Action Network (BAN), focuses on ethical reuse, recycling, and disposition of electronic equipment. This industry-led standard, updated in 2020, incorporates ISO 14001 and aims to encourage environmentally responsible electronics recycling and resource recovery, impacting EoL management practices for electronic equipment, including PV modules.
Environmental Implications of Solar Panel Disposal
E-Waste Management:
Global Impact: Considering the broader consequences of increasing solar panel e-waste. Undoubtedly renewable energy like solar energy has contributed towards minimizing carbon emissions but due to rising utilization there have been a lot of challenges at a global level:
- Solar panels consist of rare earth metals and continuous extraction and processing can lead to resource depletion and environmental degradation. With rising demand, there is a need for raw materials for manufacturing.
- The lifespan of solar panels is about 25-30 years and with growth in panel installation at commercial and residential scales large volumes of panels end up accumulating which might create E-waste management challenges.
- The recycling process for solar panels is energy-intensive and there is a need to carefully assess the energy consumption and emissions associated with the recycling.
- Global trade of E-waste from developed nations to developing countries can create huge environmental and health issues if regulations and standards are not followed properly.
Circular Economy Approach:
Materials Recovery: Exploring methods to recover valuable materials from decommissioned solar panels. with time it would be cheaper to recover materials through recycling rather than extracting through ore. Even due to rising demand, there will be the accumulation of tonnes of solar panels which would not be environmentally feasible to dump in a landfill. Currently recycling techniques used to recover most out of solar panels:
- The easiest and least amount of effort required is Mechanical recycling, in which solar panel is dismantled and materials like glass, polymers, and metals are separated with a cutting and sorting process.
- Thermal processing like pyrolysis or burning is employed to heat panels and break down valuable materials and through the leftover ashes, invaluable metals are extracted.
- The most beneficial process is Hydrometallurgical recycling in which chemical solutions are used to dissolve and extract metals like copper, silver, and indium.
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| Workers dealing with the chemical solution in the recycling plant. (Source: Image created by Chetan3105 on Gencraft) |
Conclusion
Summary of Key Points:
Solar PV Growth: Solar energy has witnessed a significant increase in capacity, rising by 35% from 2021 according to the International Energy Agency (IEA).
Dilemma of Solar Panel Disposal: The increasing demand for solar panels raises concerns about their EoL disposal, considering economic, environmental, and regulatory factors.
Economic Considerations:- Decommissioning Costs: Costs associated with dismantling and disposing of solar panels vary based on waste and recycling markets and labor costs.
- Market Dynamics: Economic factors influencing the recycling market include geographical location, raw material extraction costs, emerging recycling processes, incentives, rebates, and waste management costs.
- Cost Dynamics of Solar Panel Disposal: Recycling costs vs. landfill costs are influenced by factors such as processing, Si recovery, and landfill disposal fees.
- E-Waste Concerns: Improper disposal of solar panels as electronic waste (e-waste) poses global environmental challenges.
- Toxic Materials: Solar panels contain hazardous materials like lead, cadmium, and chemicals used in manufacturing, contributing to potential health and environmental risks.
- Different recycling methods (Glass Recycling, Mechanical Recycling, Thermal Recycling) with associated costs and revenues impact the overall economics of solar panel recycling.
- Net recycling costs vary based on scenarios, revenue sources, and methods, emphasizing the need for economically viable recycling approaches.
Industry-led initiatives and voluntary standards, such as SEIA National PV Recycling Program, Silicon Valley Toxics Coalition Solar Scorecard, NSF/ANSI 457, SERI Responsible Recycling (R2), RIOS, and e-Stewards, play a crucial role in promoting environmentally sustainable end-of-life management for PV modules.
Environmental Implications:- E-Waste Management: Addressing the global impact of increasing solar panel e-waste, considering resource depletion, environmental degradation, and challenges in recycling processes.
- Circular Economy Approach: Exploring methods like mechanical recycling, thermal processing, and hydrometallurgical recycling for materials recovery from decommissioned solar panels.
- Extended Producer Responsibility (EPR): Advocating for EPR to make manufacturers accountable for the entire lifecycle of their products, promoting sustainable disposal practices.
Call to Action:
- Promote Sustainable Practices: Encourage the solar industry to adopt and prioritize sustainable practices, including responsible disposal and recycling of solar panels.
- Research and Development: Invest in research and development to improve recycling technologies, making them more cost-effective and environmentally friendly.
- Global Collaboration: Foster international collaboration to establish consistent regulations and standards for the recycling and disposal of solar panels.
- Consumer Education: Increase public awareness about the importance of responsible disposal and recycling of solar panels, influencing consumer choices and promoting sustainable practices.