Maxeon Solar Panels. Residential solar panel efficiency

Maxeon Solar Panels

Choosing a solar panel can have a lasting impact on an organization’s energy strategy, or a homeowner’s monthly energy bill—but only when investing in a technology built and tested for the long term.

Record-setting Maxeon panels enable maximum savings and the peace of mind that comes with solar’s top durability, reliability and efficiency,1 Based on datasheet review of websites of top 20 manufacturers per IHS, as of January 2020. all backed by the industry’s longest warranty.2 Maxeon solar panels are backed by a 40-year warranty. Subject to terms and conditions. Not available in all countries. 40-year warranty requires registration, otherwise our 25-year warranty applies.

Fundamentally different, and better

The flagship Maxeon solar panel is designed to be different and proven to be better across more than five cell generations, 3.5 billion cells and 30 million panels, even in the harshest of conditions. Conventional solar cells lose power over time because of corrosion and breakage. A recent study of EU solar power plants uncovered that 41% of field failures were caused from issues surrounding the panel, such as browning and cell cracking, PID, delamination and defective backsheets. Lillo-Bravo, et. al. “Impact of Energy Losses Due to Failures on Photovoltaic Plant Energy Balance.” Energies. 2018. The unique design of Maxeon solar cells eliminates many of these causes of conventional cell failures. So your panels — and savings — continue to deliver. Year, after year, after year.

Enjoy 40 Years of Reliable Energy

Welcome to the solar industry’s longest warranty: the Maxeon 40 Year Warranty.1 Residential Maxeon solar panels are backed by a 40-year warranty. Subject to terms and conditions. 40-year warranty requires registration, otherwise our 25-year warranty applies. Commercial solar panels are backed by our 25-year warranty. It’s as exceptional as our quality solar technology. In fact, you’re 100 times more likely to return a standard solar panel than a Maxeon solar panel.2 SunPower and Conventional claim rates – A Comparative Study: SunPower DC Solar Module Warranty Claim Rate vs. Conventional Panels. SunPower Corporation. 2019.

And since our warranty covers the panel and its performance, it’s much easier to process than standard warranties in the unlikely event that you will need it. We also include broader coverage for panel repair and replacement compared to other warranties.3 Service availability varies by country and installation provider.

Our Maxeon panel’s 40-year warranty is one more way we make life better with solar.

Solar’s most innovative technology, is now backed by its most comprehensive warranty

Maxeon panels were recognized as a Top Performer in the 2022 PVEL PV Module Reliability Scorecard.

Based on data from its Product Qualification Program (PQP), the PVEL Scorecard highlights the exemplary reliability performance of solar panel manufacturers worldwide.

Unmatched reliability

Invest with confidence, knowing that Maxeon quality is proven. In actual field testing across 8 years and 800,000 panels at 264 sites, Maxeon solar panels demonstrated the lowest degradation rates in the industry, Jordan, et. al. Robust PV Degradation Methodology and Application. PVSC 2018 almost 4x stronger reliability than conventional panels.

And more reliability means more savings.

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Learn how 35 years of boundary-pushing solar DNA has made Maxeon the manufacturer of choice for many leading energy solutions providers.

Related Blogs

Solar That Thrives in Humidity

As the climate warms, more moisture is trapped in the air. While heat can limit a panel’s power, moisture can cause corrosion within cells that can ultimately lead to panel degradation and failure. Maxeon panels are designed and proven to stand up to damp heat extremes.

Solar That Can Stand up to ‘Climate Whiplash’

As the climate warms, evidence suggests we will experience more volatility between weather extremes. Not all solar performs the same in these conditions. As panels experience extreme swings between freezes and thaws, your sustainability and financial returns will be limited. Maxeon panels are designed and proven to stand up to weather extremes.

Solar That Can Take the Heat

The world is setting heat records on every continent. Solar is broadly recognized as an easy win to quickly reducing the CO2 emissions that lead to global warming—yet not all solar performs well in heat. Maxeon panels are designed and proven to stand up to warm weather extremes.

Meet the Maxeon Cell

No grid lines

Maxeon cells use back-contact conductivity, eliminating unsightly metal gridlines, enabling them to absorb more sunlight.

Solid metal backing

Metal adds massive strength to each cell, helping it resist corrosion from the elements, while making the entire panel more durable.

Thick connectors

Expanding and contracting from daily temperature swings are no problem with our built-in strain relief and thick, triple-redundant connectors.

Frequently Asked Questions

How do Maxeon solar panels differ from Conventional Panels?

Maxeon panels provide greater peace of mind than Conventional Solar Panels.1 “Conventional Panel” is a panel made with Conventional Cells. “Conventional Cells” are silicon cells that have many thin metal lines on the front and interconnect ribbons soldered along the front and back.

Maxeon panels lead the solar industry in panel efficiency2 Based on datasheet review of websites of top 20 manufacturers per IHS, as of June 2020. and deliver more bill savings by generating the most solar power and long-term solar energy in a given amount of roof space.

Over time, the advantage grows, because Maxeon panels also have the lowest degradation rate in the solar industry. While most Conventional Panels tend to degrade around 0.75%/year, Maxeon panels have proven to degrade at less than one-third of that rate, or about 0.2%/year.3 Jordan, et al, “Robust PV Degradation Methodology Application” PVSC 2018 and “Compendium of Photovoltaic Degradation Rates” PiP 2016. To translate into real results – that means a Maxeon panel delivers up to 25% more energy in its first year of operation. In year 25, that advantage grows to about 45% more energy, for an average of 35% more energy during the first 25 years.4 Maxeon 450 W, 22.2% efficient panel, compared to a Conventional Panel on same-sized arrays (370 W mono PERC, 19% efficient, approx. 2 m²).

Maxeon panels also deliver greater peace of mind, having earned the trust of experts by being more reliable and durable—and backed by an industry-leading warranty. Not only is this warranty stronger, but unlike most conventional warranties, it is based on actual field-testing data. For example, the power warranty promises no more than a 0.25%/ year power drop. This is backed by a study of more than 230MW across 149 actual global sites using a methodology developed in collaboration with NREL. We also know from actual field data that only 0.005% or 1 in 20,000 Maxeon panels have been returned under warranty.5 A Comparative Study: DC Solar Module Warranty Claim Rate vs. Conventional Panels. 2019. Lastly, Maxeon panels are built with our customers in mind, which means higher sustainability standards than Conventional Panels. Maxeon panels have pioneered sustainability efforts in solar manufacturing, and have been recognized with the prestigious Cradle to Cradle Certified™ Bronze designation for direct current (DC) panels. The Cradle to Cradle designation demonstrates the products’ quality based on rankings of material health, material reutilization, renewable energy use, water stewardship, and social fairness.

Maxeon panels were also the first and only solar panel to disclose its ingredients through the Declare label – available for all Maxeon 2 and 3 panels. In March 2020, our Mexicali, Mexico manufacturing facility was re-certified by NSF Sustainability as Zero Waste to Landfill – and remains the only solar panel manufacturing facility to achieve this. The certification means that this facility diverts more than 99% of its waste, with 1% or less going to landfills.

How do Maxeon Performance solar panels differ from the flagship Maxeon panel technology?

Maxeon Performance solar panels utilize high efficiency mono PERC cells to deliver higher reliability and efficiency than Conventional Cells. For more information on Performance Panels, visit the Performance panels page.

The Maxeon panel advantage begins with its cell. The Maxeon cell is a fundamentally different design from any other cell on the market, starting with a solid copper foundation that is unique in the solar industry.

In contrast, what appears to be metal on the front and back of a Conventional Cell is actually conductive paste made of tiny bits of silver and aluminum baked onto the silicon wafer. In fact, the process of making those cells is very similar to screen-printing a design on a tee-shirt: you create a template, wipe the paint across the template and then remove the template to leave the paint where you want it on the tee-shirt, and then bake the tee-shirt to cure the paint onto the fabric. A similar screen-printing process is used to apply the thin lines of metal paste on the front, and the full-coverage metal paste on the back, to create a Conventional Solar Cell. Unlike the strength of the solid copper foundation of the Maxeon cell, the metal paste of the Conventional Cell offers almost no strength to the thin silicon wafer. This fundamental design difference creates the weakness you can find through basic laboratory testing.

What is the typical performance advantage gained from using Maxeon panels?

A Maxeon solar panel delivers up to 25% more energy than a Conventional Panel in its first year of operation. In year 25, the difference would grow to about 45% more energy, for an average of 35% more energy during the first 25 years.1 Maxeon 450 W, 22.2% efficient panel, compared to a Conventional Panel on same-sized arrays (370 W mono PERC, 19% efficient, approx. 2 m²). Maxeon solar panels are predicted to have a useful life of more than 40 years.2 40-year Useful Life Whitepaper. 2013.

How much do Maxeon panels cost?

With solar, as with many things, “you get what you pay for.” Not all solar systems are alike. The quality of the technology matters in the long run. The durability, reliability and efficiency of solar panels can vary widely by manufacturer. If you settle for Conventional Panels that might cost less out-of-, you can expect to see average (or below average) results and less savings over time.

A higher quality panel might cost a little more up front, but you will see more predictable performance in the long run. Maxeon panels generate more energy, last longer, are backed by a stronger warranty, and are produced more sustainably than Conventional Panels.

Sunny superpower: solar cells close in on 50% efficiency

For solar cells, efficiency really matters. This crucial metric determines how much energy can be harvested from rooftops and solar farms, with commercial solar panels made of silicon typically achieving an efficiency of 20%. For satellites, meanwhile, the efficiency defines the size and weight of the solar panels needed to power the spacecraft, which directly affects manufacturing and launch costs.

To make a really efficient device, it is tempting to pick a material that absorbs all the Sun’s radiation – from the high-energy rays in the ultraviolet, through to the visible, and out to the really long wavelengths in the infrared. That approach might lead you to build a cell out of a material like mercury telluride, which converts nearly all of the Sun’s incoming photons into current-generating electrons. But there is an enormous price to pay: each photon absorbed by this material only produces a tiny amount of energy, which means that the power generated by the device would be pitiful.

Hitting the sweet spot

A better tactic is to pick a semiconductor with an absorption profile that optimizes the trade-off between the energy generated by each captured photon and the fraction of sunlight absorbed by the cell. A material at this sweet spot is gallium arsenide (GaAs). Also used in smartphones to amplify radio-frequency signals and create laser-light for facial recognition, GaAs has long been one of the go-to materials for engineering high-efficiency solar cells. These cells are not perfect, however – even after minimizing material defects that degrade performance, the best solar cells made from GaAs still struggle to reach efficiencies beyond 25%.

Further gains come from stacking different semiconductors on top of one another, and carefully selecting a combination that efficiently harvests the Sun’s output. This well-trodden path has seen solar-cell efficiencies climb over several decades, along with the number of light-absorbing layers. Both hit a new high last year when a team from the National Renewable Energy Laboratory (NREL) in Golden, Colorado, unveiled a device with a record-breaking efficiency of 47.1% – tantalizingly close to the 50% milestone (Nature Energy 5 326). Until then, bragging rights had been held by structures with four absorbing layers, but the US researchers found that six is a “natural sweet spot”, according to team leader John Geisz.

Getting this far has not been easy, because it is far from trivial to create layered structures from different materials. High-efficiency solar cells are formed by epitaxy, a process in which material is grown on a crystalline substrate, one atomic layer at a time. Such epitaxial growth can produce the high-quality crystal structures needed for an efficient solar cell, but only if the atomic spacing of each material within the stack is very similar. This condition, known as lattice matching, restricts the palette of suitable materials: silicon cannot be used, for example, because it is not blessed with a family of alloys with similar atomic spacing.

Devices with multiple materials – referred to as multi-junction cells – have traditionally been based on GaAs, the record-breaking material for a single-junction device. A common architecture is a triple-junction cell comprising three compound semiconductors: a low-energy indium gallium arsen­ide (InGaAs) sub-cell, a medium-energy sub-cell of GaAs and a high-energy sub-cell of indium gallium phosphide (InGaP). In these multi-junction cells, current flows perpendicularly through all the absorbing layers, which are joined in series. With this electrical configuration, the thickness of every sub-cell must be chosen so that all generate exactly the same current – otherwise any excess flow of electrons would be wasted, reducing the overall efficiency.

Bending the rules

Key to the success of NREL’s device are three InGaAs sub-cells that excel at absorbing light in the infrared, which contains a significant proportion of the Sun’s radiation. Achieving strong absorption at these long wavelengths requires InGaAs compositions with a significantly different atomic spacing to that of the substrate. Additionally, their device has been designed with intermediate transparent layers made from InGaP or AlGaInAs to keep material imperfections in check. Grading the composition of these buffer layers enables a steady increase in lattice constant, thereby providing a strong foundation for local lattice-matched growth of sub-cells that are not riddled with strain-induced defects.

The NREL team, which has pioneered this approach, advocates the so-called “inverted variant” structure. With this architecture, the highest energy cell is grown first, followed by those of decreasing energy, so that the cells lattice-matched to the substrate precede the growth of graded layers. This approach improves the quality of the device, while the fabrication process also results in the removal of the substrate – a step that could trim costs by enabling the substrate to be reused.

One other technique that can further boost solar-cell efficiency is to FOCUS sunlight on the cells, either with mirrors or lenses. The intensity of light on a solar cell is usually measured in “suns”, where one sun is roughly equivalent to 1 kW/m 2. Concentrated sunlight increases the ratio of the current produced when the device is illuminated compared to when it is in the dark, thereby boosting the output voltage and increasing the efficiency. The gain is considerable: the NREL device achieves a maximum efficiency of just 39.2% when tweaked to optimize efficiency without any concentration, a long way short of the 47.1% record.

When Geisz and colleagues assessed how the performance of their six-junction cell varies with concentration, they found that peak efficiency occurs at 143 suns. Nevertheless, the device still produces a very impressive 44.9% efficiency at 1116 suns, which would generate a large amount of power from a very small device. As a comparison, a record-breaking cell operating at 500 suns could deliver the same power as a commercial solar panel from just one-thousandth of the chip area. At such high concentrations, however, steps must be taken to prevent the cell from overheating and diminishing performance.

Just over a decade ago, this approach to generating power from high-efficiency cells spawned a ­concentrating photovoltaic (CPV) industry, with a clutch of start-up firms producing systems that tracked the position of the Sun to maximize the energy that could be harvested from focusing sunlight on triple-junction cells. Unfortunately, this fledgling industry came up against the unforeseeable double whammy of a global financial crisis and a flooding of the market with incredibly cheap silicon panels produced by Chinese suppliers. The result was that so few CPV systems were deployed that even on a sunny day when all operate at their peak, their global output totals less than one-tenth of the power of a typical UK nuclear power station.

Extra-terrestrial encounters

Far greater commercial success for makers of multi-junction cells has come from powering satellites, most recently buoyed by the rollout of satellite broadband by companies such as OneWeb and Starlink. The key advantage here is that high-efficiency cells can drive down the costs of making and launching each satellite. As well as reducing the number of cells needed to power the spacecraft, higher efficiencies shrink both the size and weight of the solar panels that form the “wings” of the satellite. While launch costs have plummeted over the last few decades, satellite operators can still expect to pay almost 3000 per kilogram to get their spacecraft into orbit – and thousands of satellites are due to be deployed over the next few years.

For a solar cell in space, the crucial metric is the value at the end of its lifetime – after the device has been bombarded by radiation

However, for a solar cell in space, the crucial metric is not the initial efficiency but the value at the end of its intended lifetime after the device has been bombarded by radiation. Compound semiconductors hold up to this battering far better than those made from silicon. Early studies showed that the difference in efficiency of compound semiconductors rises with age from 25% to 40–60%, which ensured the dominance of triple-junction cells for space applications. Even so, the efficiencies of the best commercial cells for satellites remain limited to around 30–33%. This is partly because the solar spectrum beyond our atmosphere has a stronger contribution in the ultraviolet, where it is much harder to make an efficient cell, and partly because there are no concentrating optics to FOCUS sunlight onto the cell.

To drive down the watts-per-kilogram of solar power in space, a US team working on a project known as MOSAIC (micro-scale optimized solar-cell arrays with integrated concentration) has been making a compelling case for CPV in space. The team points out that it should be relatively easy to orientate the solar panels on a satellite to maximize power generation with lenses in front of the cells shielding them from radiation. Concentrations must be limited to no more than around 100 suns, however, because cells in space cannot be cooled by convection, only by heat dissipation through radiation and conduction.

For CPV to have a chance of succeeding in space, the large and heavy solar modules used in early terrestrial systems must be replaced with a significantly slimmed-down successor. Technology pioneered by project partner Semprius, a now defunct CPV system maker, excels in this regard. The firm developed a process that uses a rubber stamp to parallel-print vast arrays of tiny cells, each one subsequently capped by a small lens.

The best results have come from stacking a dual-junction GaAs-based cell on top of an InP-based triple-junction cell separated by a very thin dielectric polymer. Current cannot pass through this polymer film, so separate electrical connections are made to extract the current from each cell independently. While this doubles the number of electrical connections, it eliminates the need for current matching between the two devices. Lifting this restriction gives greater freedom to the design, potentially enabling this approach to challenge the efficiency of NREL’s record-breaking device under high concentrations. Operating at 92 suns under illumination which mimics that in space, the team’s latest device, still to be fully optimized, has an efficiency of 35.5%.

Towards 50%

The NREL researchers know what they need to do to break the 50% barrier. The goal they are chasing is to cut the resistance in their device by a factor of 10 to a value similar to that found in their three- and four-junction cousins. They are also well aware of the need to bring down the cost of producing such complex multi-junction cells.

Also chasing the 50% efficiency milestone is a team led by Mircea Guina from Tampere University of Technology in Finland. Guina and colleagues are pursuing lattice-matched designs with up to eight junctions, including as many as four from an exotic material system known as dilute nitrides – a combination of the traditional mix of indium, gallium, arsenic and antimonide, plus a few per cent of nitrogen.

Dilute nitrides are notoriously difficult to grow. Back in the 1990s, German electronics powerhouse Infineon developed lasers based on this material, but they were never a commercial success. recently, Stanford University spin-off Solar Junction showcased the potential of this material in solar cells. Although the start-up went to the wall when CPV flopped, devices produced by the company grabbed the record for solar efficiency in 2011 and raised it again in 2012 with triple-junction designs. Guina and co-workers are well positioned to take their technology further. They have made progress in producing all four of the dilute nitride sub-cells needed to produce record-breaking devices, and their efforts are now focused on optimizing the high-energy junction. The team’s work has been delayed due to the COVID-19 pandemic, but Guina believes that the approach could break the 50% barrier, possibly raising the bar as high as 54%.

There is still a question of impetus, however. The lack of commercial interest in terrestrial CPV may well encourage Guina to change direction and FOCUS on chasing the record for space cells with no concentration. Much of today’s multi-junction solar-cell research is not focusing on power generation here on Earth, so while that 50% milestone is tantalizingly close, it might not be broken anytime soon.

Richard Stevenson is editor of Compound Semiconductor magazine, e-mail richardstevenson@zoho.com

The Best Ways to Maximize Solar Panel Efficiency

Energy efficiency is an important factor to consider as you shop for home solar panels, but what does energy efficiency mean? We’re here to help you make sense of solar panel efficiency, and we’ll help you maximize it so you can get the most out of your home solar system.

Want an industry-leading solar system for as little as 0 down? Schedule a solar consultation with one of our expert Solar Advisors today.

How Efficient Are Solar Panels?

To determine solar panel efficiency, sometimes referred to as photovoltaic conversion efficiency, we measure how much energy from sunlight is transformed into electricity. 1 The average commercial solar panel converts 17-20% of sunlight into electricity. 2 While 20% might not sound like a lot, it’s enough to keep the average American home powered throughout the day. Even the best semiconductors only capture a fraction of the light that strikes them. 3 Much of the light that strikes solar panels is reflected back, passes through the panel, or is converted into heat instead of electricity. 3 That’s why the residential solar panels you often see appear dark blue or black. 4 These “anti-reflection” coatings ensure the solar panels absorb as much sunlight as possible to maximize efficiency. 4

Do Solar Panels Degrade over Time?

As with most technologies, solar panels will naturally produce less energy over time. This reduced power output is called the degradation rate. The median solar panel degradation rate is about 0.5%, which simply means that a solar panel’s energy production will decrease at a rate of 0.5% per year. 5 After 20 years, your panels should still be working at about 90% of its original output.

While solar systems typically last upwards of 20 years, repairing and replacing a solar energy system can come at a high cost. 6 When you lease a solar system with Sunrun, all you have to do is pay for the power—we’ll take care of the rest. Our solar lease includes free system monitoring, maintenance, and repairs so you can enjoy 25 years of worry-free, clean energy.

How Does Weather Affect Solar Panel Efficiency?

Even in below-freezing weather, solar panels turn sunlight into electricity. That’s because solar panels absorb energy from our sun’s abundant light, and not from the sun’s heat. In fact, cold climates are actually optimal for solar panel efficiency. 7 As long as sunlight is hitting a solar panel, it will generate electricity. Less output during the winter months will primarily be due to shorter daylight hours, or possibly heavy snow.

This doesn’t mean that solar panel output will decrease in warmer weather; any diminished efficiency is balanced out thanks to more daylight hours during the spring and summer months. 7

Do Solar Panels Work in Rain and Snow?

If your winters look cloudy, rainy, snowy, or all of the above, not to worry. Solar panels can still generate electricity under these conditions, too. While solar panels are most productive in direct sunlight, they can still use diffuse or indirect sunlight (radiation) to generate energy. 8

Even though energy production decreases with increasingly dense Cloud cover, panels continue working to a greater capacity than one may expect. Rain also helps wash away dust on panels to keep them operating efficiently. 9

During times of heavy snow accumulation, solar panels’ dark, reflective glass accelerates snow melt so that it slides off before it can hamper performance. Rooftop solar panels are also typically tilted up at 30 to 45 degrees, which keeps snow from accumulating, but only to a point. 11 In comparison, a light dusting of snow is likely to blow off or disappear rapidly.

In fact, on cold, clear days, snow from the ground can reflect extra sunlight onto your solar panels like a mirror. This “albedo effect” enables panels to produce even more electricity in the cold. 10

If your panels require more than a routine hosing down or require you to get on the roof, we highly urge you to contact a trusted solar provider to receive professional assistance.

Three Tips on Maintaining Solar Panel Efficiency

While solar panels generally require little maintenance, it’s still important to inspect your solar panels from time to time and monitor their performance. Here are a few tips to ensure your solar installation is working at its full capacity: 12

Keep your panels clear of debris and other damaging materials. While rain is generally sufficient to keep your panels clean, you may want to consider a professional cleaning if you ever notice your panels aren’t working at their full capacity.

Energy Efficiency vs. Cost Efficiency

While solar panel efficiency is important to consider, cost efficiency will likely be the most relevant factor in your search for a home solar panel system. Sunrun ensures you have a cost-efficient system in three ways:

We only recommend solar if it has the potential to save you money. Sunrun will help you determine whether a solar panel system has the potential to cut the cost of your current electricity rates. Our easy-to-use Product Selector will ask you for your average monthly electricity bill so our Solar Advisors can determine if solar makes financial sense for you.

Renewable Energy and Efficient Solar Panels for Your Energy Needs

A reputable residential solar company will guarantee reliable solar panel production and dependable customer service for decades to come. With over 20 years of experience, Sunrun is committed to creating a clean energy future for all.

See why over 600,000 Americans across the country have partnered with Sunrun and get a solar consultation today. You can also use our easy Product Selector to get a solar system that’s custom-fit to meet your needs.

• 1. Photovoltaic Energy Factsheet
• 2. Solar Energy Optics: expanding efficiency
• 3. Solar panels are more efficient than you’ve heard. This material could make them even better.
• 4. Solar Performance and Efficiency
• 5. Lifetime of PV Panels
• 6. How Much Do Solar Panels Cost?
• 7. How Does Temperature Affect Solar Panels?
• 8. Direct, Diffuse and Reflected Radiation
• 9. Just a spoonful of solar panel cleaning, helps the revenue go up – the revenue go up!
• 10. Solar Panels Work Great In Snowy Regions, Research Shows
• 11. Let it Snow: How Solar Panels Can Thrive in Winter Weather
• 12. How Much Does It Cost To Clean And Maintain Solar Panels?
• 13. Short-term Energy Outlook

The Dark Side of Solar Power

Solar energy is a rapidly growing market, which should be good news for the environment. Unfortunately there’s a catch. The replacement rate of solar panels is faster than expected and given the current very high recycling costs, there’s a real danger that all used panels will go straight to landfill (along with equally hard-to-recycle wind turbines). Regulators and industry players need to start improving the economics and scale of recycling capabilities before the avalanche of solar panels hits.

It’s sunny times for solar power. In the U.S., home installations of solar panels have fully rebounded from the Covid slump, with analysts predicting more than 19 gigawatts of total capacity installed, compared to 13 gigawatts at the close of 2019. Over the next 10 years, that number may quadruple, according to industry research data. And that’s not even taking into consideration the further impact of possible new regulations and incentives launched by the green-friendly Biden administration.

Solar’s pandemic-proof performance is due in large part to the Solar Investment Tax Credit, which defrays 26% of solar-related expenses for all residential and commercial customers (just down from 30% during 2006–2019). After 2023, the tax credit will step down to a permanent 10% for commercial installers and will disappear entirely for home buyers. Therefore, sales of solar will probably burn even hotter in the coming months, as buyers race to cash in while they still can.

Tax subsidies are not the only reason for the solar explosion. The conversion efficiency of panels has improved by as much as 0.5% each year for the last 10 years, even as production costs (and thus prices) have sharply declined, thanks to several waves of manufacturing innovation mostly driven by industry-dominant Chinese panel producers. For the end consumer, this amounts to far lower up-front costs per kilowatt of energy generated.

This is all great news, not just for the industry but also for anyone who acknowledges the need to transition from fossil fuels to renewable energy for the sake of our planet’s future. But there’s a massive caveat that very few are talking about.

Panels, Panels Everywhere

Economic incentives are rapidly aligning to encourage customers to trade their existing panels for newer, cheaper, more efficient models. In an industry where circularity solutions such as recycling remain woefully inadequate, the sheer volume of discarded panels will soon pose a risk of existentially damaging proportions.

To be sure, this is not the story one gets from official industry and government sources. The International Renewable Energy Agency (IRENA)’s official projections assert that “large amounts of annual waste are anticipated by the early 2030s” and could total 78 million tonnes by the year 2050. That’s a staggering amount, undoubtedly. But with so many years to prepare, it describes a billion-dollar opportunity for recapture of valuable materials rather than a dire threat. The threat is hidden by the fact that IRENA’s predictions are premised upon customers keeping their panels in place for the entirety of their 30-year life cycle. They do not account for the possibility of widespread early replacement.

Our research does. Using real U.S. data, we modeled the incentives affecting consumers’ decisions whether to replace under various scenarios. We surmised that three variables were particularly salient in determining replacement decisions: installation price, compensation rate (i.e., the going rate for solar energy sold to the grid), and module efficiency. If the cost of trading up is low enough, and the efficiency and compensation rate are high enough, we posit that rational consumers will make the switch, regardless of whether their existing panels have lived out a full 30 years.

As an example, consider a hypothetical consumer (call her “Ms. Brown”) living in California who installed solar panels on her home in 2011. Theoretically, she could keep the panels in place for 30 years, i.e., until 2041. At the time of installation, the total cost was 40,800, 30% of which was tax deductible thanks to the Solar Investment Tax Credit. In 2011, Ms. Brown could expect to generate 12,000 kilowatts of energy through her solar panels, or roughly 2,100 worth of electricity. In each following year, the efficiency of her panel decreases by approximately one percent due to module degradation.

Now imagine that in the year 2026, halfway through the life cycle of her equipment, Ms. Brown starts to look at her solar options again. She’s heard the latest generation of panels are cheaper and more efficient — and when she does her homework, she finds that that is very much the case. Going by actual current projections, the Ms. Brown of 2026 will find that costs associated with buying and installing solar panels have fallen by 70% from where they were in 2011. over, the new-generation panels will yield 2,800 in annual revenue, 700 more than her existing setup when it was new. All told, upgrading her panels now rather than waiting another 15 years will increase the net present value (NPV) of her solar rig by more than 3,000 in 2011 dollars. If Ms. Brown is a rational actor, she will opt for early replacement. And if she were especially shrewd in money matters, she would have come to that decision even sooner — our calculations for the Ms. Brown scenario show the replacement NPV overtaking that of panel retention starting in 2021.

See more HBR charts in Data Visuals

If early replacements occur as predicted by our statistical model, they can produce 50 times more waste in just four years than IRENA anticipates. That figure translates to around 315,000 metric tonnes of waste, based on an estimate of 90 tonnes per MW weight-to-power ratio.

Alarming as they are, these stats may not do full justice to the crisis, as our analysis is restricted to residential installations. With commercial and industrial panels added to the picture, the scale of replacements could be much, much larger.

The High Cost of Solar Trash

The industry’s current circular capacity is woefully unprepared for the deluge of waste that is likely to come. The financial incentive to invest in recycling has never been very strong in solar. While panels contain small amounts of valuable materials such as silver, they are mostly made of glass, an extremely low-value material. The long life span of solar panels also serves to disincentivize innovation in this area.

As a result, solar’s production boom has left its recycling infrastructure in the dust. To give you some indication, First Solar is the sole U.S. panel manufacturer we know of with an up-and-running recycling initiative, which only applies to the company’s own products at a global capacity of two million panels per year. With the current capacity, it costs an estimated 20–30 to recycle one panel. Sending that same panel to a landfill would cost a mere 1–2.

The direct cost of recycling is only part of the end-of-life burden, however. Panels are delicate, bulky pieces of equipment usually installed on rooftops in the residential context. Specialized labor is required to detach and remove them, lest they shatter to smithereens before they make it onto the truck. In addition, some governments may classify solar panels as hazardous waste, due to the small amounts of heavy metals (cadmium, lead, etc.) they contain. This classification carries with it a string of expensive restrictions — hazardous waste can only be transported at designated times and via select routes, etc.

The totality of these unforeseen costs could crush industry competitiveness. If we plot future installations according to a logistic growth curve capped at 700 GW by 2050 (NREL’s estimated ceiling for the U.S. residential market) alongside the early-replacement curve, we see the volume of waste surpassing that of new installations by the year 2031. By 2035, discarded panels would outweigh new units sold by 2.56 times. In turn, this would catapult the LCOE (levelized cost of energy, a measure of the overall cost of an energy-producing asset over its lifetime) to four times the current projection. The economics of solar — so bright-seeming from the vantage point of 2021 — would darken quickly as the industry sinks under the weight of its own trash.

Who Pays the Bill?

It will almost certainly fall to regulators to decide who will bear the cleanup costs. As waste from the first wave of early replacements piles up in the next few years, the U.S. government — starting with the states, but surely escalating to the federal level — will introduce solar panel recycling legislation. Conceivably, future regulations in the U.S. will follow the model of the European Union’s WEEE Directive, a legal framework for the recycling and disposal of electronic waste throughout EU member states. The U.S. states that have enacted electronics-recycling legislation have mostly cleaved to the WEEE model. (The Directive was amended in 2014 to include solar panels.) In the EU, recycling responsibilities for past (historic) waste have been apportioned to manufacturers based on current market share.

A first step to forestalling disaster may be for solar panel producers to start lobbying for similar legislation in the United States immediately, instead of waiting for solar panels to start clogging landfills. In our experience drafting and implementing the revision of the original WEEE Directive in the late 2000s, we found one of the biggest challenges in those early years was assigning responsibility for the vast amount of accumulated waste generated by companies no longer in the electronics business (so-called orphan waste).

In the case of solar, the problem is made even thornier by new rules out of Beijing that shave subsidies for solar panel producers while increasing mandatory competitive bidding for new solar projects. In an industry dominated by Chinese players, this ramps up the uncertainty factor. With reduced support from the central government, it’s possible that some Chinese producers may fall out of the market. One of the reasons to push legislation now rather than later is to ensure that the responsibility for recycling the imminent first wave of waste is shared fairly by makers of the equipment concerned. If legislation comes too late, the remaining players may be forced to deal with the expensive mess that erstwhile Chinese producers left behind.