Solar energy provides a clean alternative to fossil fuel sources. Yet, progress achieved can be negatively offset by used solar panels flowing into landfills. Ask any PV professional, and they will assure you that it is not their intention to contribute to e-waste. Rather, the goal is to create a circular economy that supports reuse and recycling.
PV modules make up the largest part of a solar system, and therefore have been the target of critics who question whether the solar industry can prevent waste. It’s true that some panels end up in landfills. According to Sam Vanderhoof, CEO of Recycle PV Solar, only 10% of decommissioned solar panels in the United States are recycled; the rest flow to landfills or are allocated for reuse. The primary reason for this is the cost to recycle, which varies from $15 to $45 per panel. Whereas landfills typically charge $1 to $2 per panel.
However, disposing solar panels in landfills is throwing away something of value. If the panels are still functioning, then there’s likely a resale value. If they’re truly at end-of-life, then valuable materials, such as silicon, copper, aluminum, silver, and glass can be extracted during the recycling process and reused.
Regarding resale, the concern of whether used panels are safe and functional comes into play. Instead of assuming that all used panels are trash, conduct an audit during decommissioning to determine if reuse is possible.
“Waste panels often aren’t waste,” states Adam Minter, author and journalist for Bloomberg Opinion. “They’re just degraded by time in the sun or less efficient than newer models.”
The following assessment is meant to guide PV asset managers and resellers who wish to responsibly manage decommissioned PV modules. It provides general recommendations to assess whether to resell or recycle used solar panels.
Inspect and Test
The first step in your assessment to determine whether to resell or recycle used solar panels is to conduct a hardware audit. This step should ideally take place before decommissioning; however, you can still complete a thorough audit after the fact as well.
While the PV system is still connected, inspect and test the modules. Look for any visible defects, including glue marks, scratches, snail trails, burn marks, hot spots, shattered or cracked glass, and cracked or peeling backsheets. Test module performance for open circuit voltage, short circuit current, and operating current. Once you’ve completed your inspection, document your test results and the overall condition of the panels.
Next, proceed with decommissioning and palletizing the panels. Prepare documentation on the following:
- Serial number
- Module model number
- Exact quantity
- Age (i.e. how long the panels have been in operation)
- Number of busbars
- Number of cells
- Packing condition
- Weight per pallet
- Photos (include images of the back and front sides of the panels, the label, and the packed pallets)
All these factors contribute to a comprehensive hardware audit, which serves resellers in the appraisal process. Such details also help recyclers to determine an accurate recycling cost and provide certificates of disposition for end-of-life panels.
Resale vs. Recycling
Once you’ve completed your hardware audit, the next step is to sort your solar panels into two categories – resale versus recycling. Use the following chart to determine which modules fit each category.
Source: Degradation mean power rate - 0.5 to 1.9% per year
Resell solar panels when:
- They are still functional.
- Their age (as defined by years in operation) is young enough that the panels are capable of producing power for a minimum of 10-12 years more. Note that panels with an age of 5 years or less reap a higher resale value.
- The degradation rate is equal to an average of 0.5 to 1.9% per year over the panels' total years of operation.
- They are free of defects. Or, if minor defects exist, then they're clearly stated and ideally refurbished (e.g. junction box and/or fuses, wiring have been replaced).
Recycle solar panels when:
- They fail safety tests and are beyond repair.
- They have shattered glass. Note that a new experimental repair technique for glass defects of double-glass PV modules has been found to be feasible and effective; however, this technique is currently not readily accessible in the mainstream market.
- The degradation rate exceeds the mean power rate of 0.5 to 1.9% per year over the panels' total years of operation.
- They have defective backsheets that are cracked or peeling. This defect is a fire hazard. However, advances in repair solutions, such as repair tape and silicon sealant, have been adopted by some remanufacturing facilities. Depending on their deterioration condition (e.g. minor cracks), backsheets may be repaired.
In addition to the above-mentioned resale guidelines, value-added services increase the resale of used solar panels as well. The secondary market boasts a network of solutions providers who specialize in repair, remarketing, and other services. Solutions providers who offer repair and remanufacturing typically include service warranties that range from 1 to 5 years. Some resellers include a 30-day money-back guarantee, which affords the buyer time to inspect and test the panels upon delivery.
Now that you’ve sorted out which panels to resell versus recycle, your next steps are to prepare the functioning panels for remarketing and arrange delivery to a recycling partner for end-of-life panels.
For resale, you’ll need to decide whether you want to handle the sale in-house or contract with a solar equipment broker. Either way, online exchanges, like EnergyBin, make it easy to connect to reputable resellers and wholesale buyers.
For recycling, you’ll want to deal with a qualified partner. Ensure your recycling partner has all relevant environmental permits and/or licenses for their region(s) of operation. Verify that your partner does not export untreated waste. Ask for a certificate of disposition detailing your panels.
Note that some recycling facilities may also specialize in remarketing services or partner with refurbishers. They may offer you an incentive for those modules that can be repaired and resold, which offsets the cost of recycling.