Table of Contents:
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Manufacturing and transporting solar panels generate a significant carbon footprint, but that footprint is offset by energy savings during the operational stage of their life cycle.
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The most resource-intensive stage of a solar panel’s life is the extraction of the raw materials used to make them.
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While they do generate some emissions, solar panels have a vastly lower carbon footprint than fossil fuel-based energy.
The environmental benefits of solar panels are often talked about in the immediate sense, in terms of energy savings compared to grid energy derived from fossil fuels. While these metrics are key selling points for solar energy systems, they aren’t the complete picture. To understand their true carbon footprint, it’s important to take the entire solar panel life cycle into account.
In this article, we go over the stages in a solar panel’s life, examining the environmental impact at each stage. You’ll also learn what happens to panels at the end of their working lives, as well as what the future may hold for solar technology and its carbon footprint.
Solar panel life cycle overview
Every stage of a solar panel’s life, from sourcing its raw materials to disposing of it, is a factor in its environmental impact. Taking the entire life cycle into account gives you the complete picture of when and how your solar panels add to and reduce your carbon footprint. It also gives you the most accurate estimate of your overall energy return on investment (EROI).
We’ll explore these stages in detail later in the article, but we’ve listed some of the key information about each stage in the table below.
| Life cycle phase | Description | Key activities | Main environmental considerations |
|---|---|---|---|
| Raw material extraction | Sourcing of raw materials like quartz, silver, aluminum, and copper. | Mining, transport, refining | Habitat disruption, energy use, toxic runoff |
| Material processing | Conversion of raw materials into usable components (e.g., silicon wafers). | Purification, melting, doping, wafer slicing | High energy consumption, emissions, chemical use |
| Manufacturing | Assembly of solar cells into panels and addition of framing and encapsulants. | Cell production, panel lamination, quality control | Emissions, labor safety, material waste |
| Transportation | Delivery of finished panels to installation sites. | Packaging, shipping (often international) | Fuel consumption, packaging waste |
| Installation | Mounting of panels on rooftops or solar farms. | Structural setup, electrical integration | Land use, disruption to local ecosystems |
| Use phase (operation) | Panels generate electricity, typically 25 to 30 years. | Energy conversion, maintenance, performance monitoring | Energy generation, minimal emissions |
| Maintenance | Routine upkeep to ensure optimal performance. | Cleaning, inverter replacement, electrical inspections | Water use (cleaning), minimal waste |
| Decommissioning | Taking panels offline after their useful life. | Removal, transport to recycling or disposal facilities | Potential for breakage, hazardous material handling |
| Recycling or disposal | Treatment of end-of-life panels. | Material recovery, waste sorting, landfill or incineration | Toxic leaching, resource recovery, compliance with laws |
Material sourcing and resource extraction
The first stage of life for a solar panel is also its most resource-intensive: the extraction of the materials needed to produce them. Mining these raw materials uses substantial amounts of energy and water to power and cool mining equipment, as well as all of the resources needed by workers.
In the table below, we outline the primary materials used to make solar panels, how they are used, and how they are sourced.
| Raw material for solar panels | Use in solar panels | Sourcing method |
|---|---|---|
| Silicon | Making photovoltaic (PV) cells | Extracted from quartz sand through high-temperature furnaces |
| Silver | Producing conductive pathways in and between PV cells | Mined in open-pit and underground extraction sites |
| Aluminum | Building structural framing for panels | Bauxite ore is extracted from surface mines and then refined into alumina |
| Glass | Encapsulating PV cells in the framework | Made by melting raw materials like sand, soda ash and limestone in high-temperature furnaces |
Processing and component manufacturing
Taking those raw materials and turning them into functional components is the second part of the solar panel life cycle. This step requires the use of energy and other resources while also generating greenhouse gases.
The key processing steps in the manufacturing of solar panels include:
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Polysilicon purification: Uses the Siemens process to refine silicon to solar-grade quality.
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Wafer cutting: Large pieces of silicon ingots are sliced and chemically treated to prepare them for use in solar panels.
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Doping: Toxic chemicals like boron and phosphorus are added to silicon wafers to create positive and negative charges.
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Glass tempering: To make it more durable for use in panels, glass is heat tempered—a process in which it is heated to a high temperature then cooled rapidly, often several times.
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Aluminum extrusion: Refined aluminum is forced through a die to shape it for panel casing construction.
Module assembly and production
After the raw materials have been processed for use in solar panels, the next step is assembling the individual components into panels. While this stage does add to the carbon footprint, it is far less intense than the extraction and processing of raw materials.
The production steps for making solar panels include:
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Connecting and metallizing PV cells
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Encapsulating solar cells with ethylene-vinyl acetate (EVA)
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Laminating cells under tempered glass
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Fitting PV cell modules into framing
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Sealing the complete assemblies
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Testing solar panels for efficiency and durability
Shipping, distribution, and installation
After being assembled and tested, solar panels need to be distributed to vendors and later to installation sites. Transporting the panels adds to their carbon footprint, as container ships, trucks, and other modes of transportation burn fossil fuels to power their engines.
Installing solar panels also requires significant site preparation and supplementary infrastructure. This includes clearing roofs and other sites for steel or aluminum mounting systems used to secure the panels and other equipment.
Grid-tied solar energy systems require even more infrastructure. Technicians need to install a solar inverter to control the flow of electricity between the panels and the grid. These setups also need additional cabling to connect the solar system and the grid to each other.
Energy generation during operational lifespan
Until they become operational, every step in the life cycle of solar panels adds to their carbon footprint. However, once they are in operation, they begin to replace energy derived from fossil fuels with clean, renewable energy, effectively reducing the household’s carbon footprint in the process.
Generally speaking, solar panels have a carbon payback period of one and a half to three years. This is the time it takes for emissions savings from solar panels to fully offset the carbon footprint of producing them.
Solar panel working lifetime
Solar panels have an extensive working life, with most lasting between 25 to 30 years. Throughout this lifetime, they operate at between 15-22% efficiency, depending on the type of panel and environmental factors. Solar efficiency does degrade over time, but only at a rate of around 0.5% per year. That means most solar panels continue providing emission-free energy for more than two decades after completing their carbon payback.
Do solar components need to be replaced?
Some components need to be replaced more frequently than the panels themselves. The inverter, for example, has an average working life of 10 to 15 years. Solar batteries tend to need replacing every five to 15 years.
Does solar panel maintenance affect carbon emissions?
Maintaining solar panels has a negligible impact on their carbon footprint, as they do not require significant attention. Normal maintenance for solar panels is limited to occasional cleaning and performance checks in most cases.
End-of-life recovery and recycling
Eventually, solar panels reach the end of their working lives and need to be decommissioned. Disposing of old panels in a landfill adds significantly to their carbon footprint, but there are alternative options that are significantly better for the environment. These include:
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Reuse: Solar panels that are still functional can be refurbished and repurposed for secondary markets and lower-voltage applications like powering RVs or outdoor lighting.
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Recycling: The glass and aluminum used in solar panel housing is easy and economically efficient to recycle. Both materials can be repurposed without losing significant mass.
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Recovery: It is possible to recover the silicon used in PV cells for repurposing. However, this is still rare within the solar industry.
Some solar materials cannot be salvaged or repurposed. Toxic elements like lead, cadmium, and arsenic require regulated disposal to ensure safety.
Bottom line on the solar panel life cycle
To wrap up, we looked at the full solar panel life cycle, from raw material extraction through recycling, highlighting each stage’s environmental impact. While production and transport generate emissions, solar panels quickly offset this through decades of clean energy generation. Future improvements in technology and recycling practices are expected to further reduce their overall carbon footprint.
FAQ about solar panel life cycle
Below are a few frequently asked questions about the life cycle of solar panels:
How long does a solar panel last?
On average, solar panels last between 25 to 30 years, though they can collect energy at lower efficiency beyond that point. Longevity can be affected by the type of solar panel, the surrounding environment, and maintenance habits.
What happens to solar panels after 10 years?
After 10 years, solar panels will still work well but will have lost some efficiency. Solar panel efficiency degrades between 0.3% and 0.8% per year depending on the manufacturer and panel type.
What happens after 25 years of solar panels?
After 25 years, solar panels maintain about 80% to 90% of their original efficiency depending on the brand and type. You can still use them or for a few years or replace them with more efficient panels.