How Solar Panel Performance Changes Over Time

Solar panels are powerful energy generators that provide clean solar energy for decades, helping homeowners slash their utility bills and achieve better energy independence. However, solar panel degradation is an unfortunate fact of life, and a drop in performance is inevitable throughout the lifespan of any array. 

So, how does solar degradation affect energy efficiency, and how long do solar panels really last? Today, we answer these questions and offer tips to support long-lasting solar performance. 

Understanding Solar Panel Degradation

Entropy is a scientific concept that describes how all matter breaks down over time. Sadly, solar panels are no exception. 

What is Solar Panel Degradation?

Solar panel degradation is a gradual decline in a PV panel’s ability to convert sunlight into usable electricity. Although solar panels are highly durable, typically under warranty for 25+ years, they will naturally exhibit diminished performance throughout their lifespan. It’s important to factor in this drop in efficiency when calculating your return on investment. 

What causes solar panel degradation? Environmental effects like UV exposure, wind, and heavy snow loads are major contributors. Thermal cycling occurs when panels are heated and cooled repeatedly, stressing various components. Solar cells and encapsulating materials can also weaken over time. 

How Much Do Solar Panels Degrade Over Time?

On average, most modern solar panels degrade at a rate of 0.5% to 1% each year, meaning you can expect your panels to operate between 75% and 87.5% of their original generation capacity after 25 years. That said, some premium solar panel models have lower degradation rates closer to 0.25%. Here are some of the factors that influence these figures:

• Environmental conditions: Extreme temperatures, salty air, and climatic events like hail, sandstorms, and high winds can all impact solar performance over your panel’s lifespan. 
• UV exposure: Intense, prolonged sun exposure can break down the components within solar panels. 
• Installation and maintenance: Loose mounts, improper wiring, and insufficient maintenance can speed solar panel degradation. 
• Electrical wear and tear: Electrical components like inverters, connectors, and wiring can wear down over time, eventually failing. If microcracks develop in your panels, they can spread, affecting your output. 

Lifespan of Solar Panels

Understanding the anticipated lifespan of your solar panels, how degradation may affect performance, and the stipulations of your warranty agreement can help you plan for long-term optimization.

Expected Lifespan: How Long Do Solar Panels Last?

The average lifespan of solar panels is 25 to 30 years, but they won’t stop generating clean energy altogether once they reach a certain age. Instead, they will begin creating less energy over time. Beyond the 25-year mark, many panels continue operating at around 80% to 85% of their original capacity. With proper maintenance, your array may keep generating electricity even after 30 to 40 years. 

Warranty Insights: Protection Against Performance Drops

Most solar panels come with two types of warranties that reflect the manufacturer’s and the solar installation company’s confidence in a certain product. Product warranties cover manufacturer defects and failures, such as glass delamination and frame corrosion. Performance warranties guarantee specified energy outputs over time. For instance, they may promise that your panels will operate at 90% output for the first ten years and 80% at 25 years. 

A great solar installation company should offer high-quality warranty coverage for your solar array. Solar Energy World’s Triple Platinum 30-Year Warranty includes a labor warranty for all service-related issues, a 30-year manufacturer’s warranty on all panels and inverters, and removal and reinstallation if you need a new roof within 10 years of installation.

Impact of Degradation on Energy Savings

As your solar panels reach the end of their anticipated lifespan, degradation affects performance and impacts your bottom line. 

Efficiency Dips and Their Financial Implications

Even with proper maintenance, your solar panels may produce 0.5% to 1% less energy each year, meaning your solar array offsets less energy from your utility bill over time. For example, if your system degrades at a rate of 0.8% annually, it will operate at about 84% of its original capacity after 20 years. While this reduction in efficiency is gradual, it’s important to factor into your long-term energy savings expectations.

Homeowners participating in net metering programs may take an even harder hit, as this performance drop will be reflected in the credits reimbursed on each utility bill. 

Practical Implications: Understanding Your Long-Term ROI

In order to calculate your ROI accurately, you must factor in solar panel degradation over the lifespan of your array. After all, even a small drop in performance can add up to thousands in missed savings over 25 to 30 years. Fortunately, you can take small steps to maximize your energy savings despite inevitable degradation. 

When purchasing your array, choose high-quality Tier 1 or Tier 2 panels, which may degrade more slowly than budget-friendly alternatives. Perform regular maintenance and inspections on panels, batteries, and inverters to keep everything running efficiently. Inverters may only last 10 to 15 years, but replacing them as needed can improve overall system performance. Track your panels’ performance with live monitoring software to identify and resolve production drops before they intensify. In some cases, adding a couple of solar panels or battery backup can remedy diminished output without the need for an entirely new system. 

Factors Affecting Solar Panel Efficiency Over Time

Solar panel degradation is a fact of life, but you can take steps to counteract this natural process. 

Environmental Factors and Their Role

Solar panels perform best in cool, sunny climates, as they operate more efficiently in colder temperatures. Hot weather, humidity, and salt buildup may degrade various components over time. Consider your local environment when purchasing solar panels and set your expectations accordingly. 

You may not be able to control the weather, but you can ensure your panels are placed in the optimal position for enhanced performance. Consult with your solar installation specialist to determine the ideal tilt and orientation of panels on your rooftop. Whenever possible, eliminate any objects like tree branches that may shade your array. If some amount of localized shading is unavoidable, consider installing microinverters to minimize the impact. 

Regular Maintenance to Slow Degradation

Keeping your solar panels clean and well-maintained will go a long way to combating degradation and supporting optimal long-term performance. In some areas, rainfall may routinely remove pollen, dust, and dirt, requiring manual cleaning only twice a year. Homeowners in other locations may need to wash their panels seasonally. Ongoing solar monitoring may indicate that a cleaning is necessary, so keep an eye on your system’s performance. When cleaning your panels, use a soft brush and mild soap, avoiding harsh chemicals and abrasive tools. 

Every few months, perform a thorough inspection of your solar panel array to check for cracks, discoloration, debris, corrosion, and loose wires. Report any abnormalities to your solar installer. It’s important to schedule a professional inspection every couple of years, or annually for older systems. Your specialist will examine wiring and connections, mounting hardware, inverter function, and safety features to ensure everything is working correctly. 

Solar Energy World Can Help You Mitigate Panel Degradation

You may not be able to stop the process of solar panel degradation, but proper maintenance can help you enjoy enhanced performance for decades to come. The experts at Solar Energy World can guide you through routine upkeep procedures to ensure high energy efficiency. Get started today with a free solar estimate!