Why Do Solar Panels Degrade?

May 15, 2024

People invest in solar energy because it offers both financial and environmental benefits. Additionally, it is a non-risky long-term investment as most solar panel manufacturers predict solar panel lifespan to be 25-30 years. However, those people wonder whether solar panels degrade over time and what they can do about it.

In our blog post, we’ll explain how long solar photovoltaics last, review the degradation rate, and discuss ways to make your solar panels last as long as possible.

How Long Do Solar Panels Last?

The solar panel lifespan is around 25 years before significant degradation becomes noticeable. Many solar panel manufacturers offer a standard 25-year warranty to cover this expected lifespan to avoid problems with solar panels occurring afterward. While they may not need replacement after 25 years, their efficiency in absorbing sunlight will likely diminish.

Solar panel installation on the roof

Although it’s rare for a solar panel to go dark over time, the wear and tear could be so significant that it’s time to swap out the whole system. Besides the basic panel warranties, many manufacturers offer shorter ones for the accompanying gear. These can come in handy for extreme weather conditions.

Another aspect to consider about solar panel lifespan is that the frames that hold solar panels aren’t covered under panel warranties and might take a hit from the elements.

Furthermore, solar inverters typically last 10 to 15 years, but they work overtime, converting solar energy into your home’s power. On average, expect to spend another $1,000 to $2,000 to replace one during the lifespan of solar panels.

Factors that Impact Life Expectancy of Solar Panels

While some uncontrollable aspects like climate and severe weather can influence how long your solar system lasts, there are steps you can take to extend the life of solar panels.

QualityAs the saying goes, “You get what you pay for,” which rings true for solar panels. The tier breakdown reveals that the quality of your panels significantly impacts solar panel lifespan. To gauge what kind of output you can anticipate, check out the manufacturer’s production warranty. Companies backing their products for 25+ years demonstrate confidence in their durability, which is an excellent draw for you.
InstallationPutting your solar panels in the hands of a seasoned installer ensures that the racking will stand the test of time. Cutting corners during installation and wiring could hasten solar panel degradation. Top-notch solar companies often provide maintenance checks to ensure smooth operation and nip potential problems in the bud.
ClimateWhen it comes to solar panels, remember that the climate you install them in can make or break their lifespan and performance. Monitor how weather patterns and other factors influence average solar panel output and durability.

For instance, expect your panels to wear out faster if you’re in a hot area. Heat speeds up the breakdown of solar panel materials compared to colder regions. Also, other weather conditions like humidity, hail, and strong winds can damage your panels and their components, leading to a shorter solar panel lifespan.

MaintenanceThe low maintenance of solar panels is another significant benefit beyond cost savings and eco-friendly perks. However, a little care can go a long way if you want to prolong solar panel life expectancy.

For instance, keeping debris off your panels isn’t just about sunshine access—it prevents scratches and chips that could lead to damage. Consider cleaning your panels regularly or fitting them with critter guards to avoid such issues.

Why Do Solar Panels Degrade?

Over the anticipated 25-year lifespan of solar panels, it’s normal for performance to weaken gradually. However, one or more panels might conk out at some stage due to the six well-documented issues below. Apart from these factors, panels can suffer harm during transit or bungling during installation, which might not be revealed until years later.

Wind damage to solar panels installed over parking lot canopy shade for parked cars

Additionally, in rare instances, heavy-duty impacts from giant hailstones or other projectiles can shatter the front glass. Consider that of the six reasons mentioned, the first isn’t technically a defect but rather a slow, steady decline in solar panel efficiency over time.

Here are the six reasons behind solar system degradation and failure:

  • LID (Light-Induced Degradation) — the expected annual performance decline ranging from 0.25% to 0.7%
  • PID (Potential Induced Degradation) — the risk of long-term failure due to voltage leakage
  • General Degradation — premature failure due to water infiltration or other flaws that undermine solar panel lifespan
  • LeTID (Light and Elevated Temperature Induced Degradation) — a sudden decline in performance by 3% to 6%
  • Microcracks and hot spots — persistent issues and breakdowns from broken or damaged cells
  • Failed bypass diodes — a hitch often linked to panel shading from nearby objects

Let’s look at each aspect that undermines solar panel efficiency over time.

Light-Induced Degradation

When sunlight first hits a solar panel, a process known as ‘power stabilization‘ kicks in due to oxygen traces in the silicon wafer. This phase, a part of light-induced degradation (LID), has been extensively studied and marks the initial settling period. During this time, it’s typical for a solar panel to experience a 2% to 3% drop in its rated wattage (Wp) output within the initial few hundred hours of operation, with the full impact typically occurring within the first year.

Following this initial phase, the rate of LID significantly slows down, averaging 0.3% to 0.6% per year over the next 25+ years. However, with high-performance and best-rated solar panels from manufacturers like Sunpower and REC, LID can be as minimal as 0.25% per year due to high-purity N-type silicon cell substrates. The latter usually prolongs solar panel lifespan.

Fortunately, most manufacturers slightly exceed the panel power rating by up to 5%, which offsets much of the initial degradation and ensures the accuracy of the rated panel power (Wp). For instance, a 350-watt panel might initially generate up to 5% more power, reaching up to 368 Watts momentarily. However, this slight surplus is typically brief and may only be noticeable if the panels operate under ideal conditions.

The product description contains all the information about buying solar panels. The manufacturer’s performance warranty outlines the LID rate and the anticipated performance decline over the warranty period (typically 25 years).

Potential Induced Degradation

Another damage that seriously affects solar panel lifespan is potential induced degradation (PID). In other words, it is like a stealthy intruder sneaking in due to a high voltage gap between the semiconductor material (cell) and other parts of the module (glass, mount, or aluminum frame). This voltage gap sparks a current leak, causing negative and positive ions to migrate.

Thus, negative ions slip away through the aluminum frame, while positive ions (sodium ions) reach the cell surface. These intruders “contaminate” the cell, dialing down its photovoltaic effect and causing power losses. PID’s impact can be hefty, with potential losses of up to 20%, and the effects aren’t immediately apparent — it might take several months to a few years to notice the damage.

PID is intricately tied to environmental conditions like humidity and temperature, as well as the setup of the PV system, including grounding and the types of modules and cells used.

General Degradation

In addition to the notorious PID and LID troubles, panels can also face graver issues stemming from the disintegration of their protective layers, which are meant to shield cells from the outdoor elements. The chief culprit here is a back-sheet failure. While the front glass shields against rain, hail, and grime, the plastic back sheet — either white or black — guards the cells’ rear from water, humidity, and scratches.

Hail damage to solar collectors on the roof of a house after a thunderstorm

However, due to shoddy material choices and negligent quality checks, UV rays can chip away at either the encapsulant or the rear shield, leading to cracking or solar degeneration over time. This breakdown can lead to more serious problems with solar panels, like moisture seepage, rust, and electrical leaks.

LeTID

Most modern solar panels sport PERC solar cell tech, a boost for efficiency that’s been embraced by the global solar panel community. Yet, a recent discovery has shed light on a potential flaw of this type: P-type PERC cells might suffer from LeTID or light and elevated temperature-induced degradation.

How does it differ from the LID mentioned above? LeTID mirrors LID, but losses from LeTID have hit highs of 6% in the first year. If the manufacturer does not tackle this head-on, this could cause different problems with solar panels, leading to lackluster performance and potential warranty trouble.

Thankfully, N-type silicon cells from some manufacturers can avoid LeTID’s effect. Moreover, other manufacturers using P-type poly and mono PERC have fine-tuned their production processes to mitigate or altogether sidestep LeTID trouble. Q Cells made a splash by touting anti-LeTID technology across their panel range.

Microcracks and Hot Spots

Do solar panels wear out from microcracks? Unfortunately, they do.

Micro-cracks can be like ghosts — hard to spot at first glance. These tiny fractures in solar cells tend to reveal themselves on older panels. While they don’t always cause disaster, panels with a few cracks can still work for years, delivering decent performance.

However, when these cracks ramp up internal resistance and disrupt the current flow, they can create trouble spots or “hot cells.” This becomes a real headache if the crack is sizable or stretches across the entire cell.

Thankfully, most modern panels now boast half-cut cells with multi-busbars, a feature that largely neutralizes the harmful effects of micro-cracks and avoids serious problems with solar panels.

Solar panel microcracks

Source: LinkedIn

Hot spots are another concern affecting solar panel lifespan. When an internal fault or severe micro-crack messes with the current flow, resistance spikes, generating heat that spirals into more resistance and even more heat — a recipe for a hot spot. In severe cases, this heat buildup can even scorch the cell.

Spotting hot spots and micro-cracks can be challenging. The only way to spot trouble is often with a specialized thermal imaging camera, which flags cell temperature discrepancies.

Watch out! Regular shading from rooftop obstacles can also gradually brew hot spots over the years because of the reverse current effect from shaded cells.

Failed Bypass Diodes

When bypass diodes in solar panels kick into gear due to serious shading, they can end up siphoning off electrical energy as heat. As a result, this heat buildup can cause problems with solar panels if the diodes keep running nonstop under shady conditions. It can even spark hot spots and panel meltdowns.

Factors increasing the risk of diode breakdown are:

  • Scorching temperatures
  • Humidity
  • The constant strain of operation
  • The degree of shading

Spotting a failed bypass diode can be a difficulty. It’s a piece of cake in older solar setups where diodes are easy to reach but can be a real head-scratcher in many modern panels with limited access.

If you spot heavy shading on specific panels, those are prime suspects for troubleshooting. Additionally, you need to test and examine solar panels systematically if you aim to prolong solar panel lifespan.

How to Know If Anything Threats Your Solar Panel Lifespan?

A worker's hand holding a damaged solar panel with microcracks

If you suspect a dip in solar panel efficiency over time, plenty of ways exist to find out. Start by giving them a once-over visual check for any damage signs of trouble or a buildup of grime, which can drag down system performance. Sometimes, a good scrub with a gentle broom and water is all they need. Additionally, watch for any sneaky tree that casts shade on the panels.

For systems kitted out with monitoring apps or web-based tracking, it’s much easier to compare daily solar output, measured in kWh, with previous days, weeks, and months to spot any major dips or changes in performance. Local weather, seasons, and climate will also play a role. Likewise, give the inverter a once-over for glaring issues (like red lights) and check that the isolator in the switchboard has yet to trip.

Can You Make The Lifespan Of Solar Panels Longer?

You can give your solar setup a longer lease on life with some regular care and top-notch upkeep. Here’s how:

  • Partner with a trusted solar installer who offers regular check-ups. These maintenance checks can find any flaws in the panels, spot issues with the rooftop racking, and ensure the inverter runs smoothly.
  • Keep them clean: rinse them with water when they’re dirty. If dust or sand sits too long, it can lead to pesky microcracks and scratches.
  • Clear debris from the panels, like fallen branches or heavy snow. Fallen branches can outright break panels, while smaller ones can scratch and pile on the pressure if they build up.
  • Snow left to sit can freeze and cause microcracks due to the extreme cold. To ease the load and lower the risk of microcracks, it’s best to clean the panels thoroughly.

These simple steps help to prevent any possible system damage and prolong the lifespan of solar panels.

Solar Investment: Prolonging Panel Lifespan and Efficiency

As with any device, a solar setup can’t last forever. The lifespan of solar panels depends on many controlled and uncontrolled factors. They degrade slowly because of solar degeneration. However, you can get the most out of your solar investment if you regularly care and examine the system for any flaws.

Undoubtedly, solar panel efficiency will dip over time, but you won’t need to replace them after the warranty expires if your solar system works well and covers all your electricity needs.

Jed Hilton
Jed Hilton

Jed Hilton, our Founder and CEO, has over a decade of experience in the solar industry. His innovative leadership and expertise in solar technologies guide our company's vision and strategy.

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