How Long Do Solar Panels Last? A Comprehensive Guide
Sharon Lee • Updated on April 19, 2023 • [rt_reading_time postfix=”minute”] read
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When considering an investment in commercial solar, it’s logical to wonder how long solar panels last. After all, we’re talking about a significant financial investment, so you’ll want something that will be with you for the long haul.
The good news is that the longevity of solar panels has improved significantly over time as technological and material advancements have been achieved. In fact, most modern solar panels are designed to last around 30 years.
An investment in solar is a long-term investment in a reliable source of sustainable, low-cost electricity.
That said, like all good things, your solar panels won’t last forever. In this article, we’ll talk about solar panel degradation rates and things you can do to maximize the lifespan of your solar panels.
Table of Contents
Solar Power Basics
Before we get into defining the solar panel degradation rate, let’s set the stage with a few solar power basics.
Solar panels are made up of individual solar photovoltaic (PV) cells, which are thin slices of silicon that typically measure 6 inches long by 6 inches wide. Each solar cell converts sunlight into electricity in what’s called the photovoltaic effect. Multiple solar cells are assembled together to form a single rectangular shaped panel. Multiple panels are then assembled into an array to provide the solar power your business needs.
Solar panels typically contain 60 or 72 cells, though there are some on the market with as few as 32 and as many as 96 solar cells. These are typically used for specific applications like recreational vehicles and very large commercial installations, respectively.
Commercial solar panels usually have 72 solar cells and measure around 6 feet by 3.25 feet, slightly smaller than a sheet of plywood.
Solar Panels Degrade Over Time
In the introduction, we noted that the average solar panel lasts for 30 years. But it’s worth noting that your solar panels don’t just stop producing electricity on their 30th birthday.
Rather, what typically happens is that the efficiency, or the amount of energy production from the panels, degrades very slowly over time.
Solar panel output
A solar panel’s efficiency is the amount of sunlight (solar irradiance) that falls on the solar panel that can be converted into usable electricity. Modern solar panel efficiencies range between 16 and 22%, with an average of just over 20%. The more efficient the solar panel the more electricity it can generate.
The industry standard degradation rate for solar panels is between 0.3% and 0.8% annually. According to a study conducted by the National Renewable Energy Laboratory, the median degradation rate for solar panels is 0.5%.
Calculating your solar panel degradation rate
So what does solar panel degradation look like in the real world?
If we assume a median degradation rate of 0.5%, that means your solar panels will be producing 87.5% of their original power output in year 25. At this point, you may start to notice the degradation of your panels because your system is producing less energy.
By year 30, solar panels degrade to the point that their efficiency rate is below what the manufacturer deems optimal. But, that doesn’t mean those panels no longer produce electricity. In fact, well-maintained solar panels can function well beyond three decades – they just aren’t as efficient as they once were.
Eventually, solar panels degrade to the point that they need to be replaced.
Why solar panel degradation matters?
So, why does solar panel degradation matter? It all comes down to your bottom line – the lower the degradation rate, the more energy a solar panel will produce over its lifespan. And that means you’re really maximizing the benefits of having a solar power system.
Those benefits include:
Lower Energy Costs
Solar panels can help lower your monthly electricity bill by reducing the amount of electricity you have to purchase from your utility. The more efficient your panels are, the less electricity you need to buy.
Faster Payback
Because higher efficiency solar panels generate more energy, you’ll have to pull less power from the grid, reducing your energy bills even further. With the extra savings you’ll be able to pay off your initial investment that much faster.
Resilience
Think about how much your last major power outage cost you in terms of lost business or lost inventory. Some studies show that for a manufacturer, even a single hour of downtime can cost a company upwards of $5 million. That means your solar panels could more than pay for themselves during the next grid power outage.
Reduced Carbon Footprint
When you reduce the amount of grid energy you use by installing solar panels, you also reduce the greenhouse gas emissions of your business. Grid electricity is still generated primarily by burning fossil fuels, and while utilities are integrating renewable energy into their portfolios, there’s a long way to go before we can call our electric grid green.
Plus, if you replace a diesel backup generator with a solar plus storage system, you can see even greater carbon emissions reductions.
What causes solar panel degradation?
There are a number of things that can contribute to the degradation of your solar panels.
The quality of the materials
The quality of the materials is one of the biggest determinants in how long solar panels last. Different brands have different degradation rates; generally, higher quality panels from premium manufacturers have a lower degradation rate.
The age of the solar panel is also important. Degradation rates have improved over the years thanks to technological advancements, and newer panels don’t degrade as quickly as older models.
Solar panel manufacturers offer a variety of warranties for their products, and the length of time the company stands behind its product is a good indicator of how long its solar panels last. You’ll want to look for panels with a 25 or 30-year performance warranty, which means the manufacturer guarantees the panels will produce a specified amount of electricity during that timeframe.
The quality of your solar partner
The partner you select for your commercial solar panel installation is also a key factor when it comes to extending the life of your system.
You’ll want to work with a provider that has experience installing, operating, and maintaining commercial solar panel systems. At Velo Solar, we take a design-build approach to solar energy systems.
We believe design-build, also called EPC 2.0, is the most efficient and flexible project delivery method. Design-build is more of a long term partnership between the provider and the customer that meets you where you are today and allows you to plan for the future.
One of the hallmarks of this type of solar provider is that they have entire design-build teams on staff, including engineering, design, construction, software, energy storage, and solar system optimization experts. The provider collaborates with you to design a system that meets your energy and budgetary needs, as well as your timeline.
A reputable solar provider will ensure that you have the best materials for your project and that your system is installed correctly – both of which will extend the life of your solar panel system.
How to Extend the Lifespan of Solar Panels
While modern commercial solar panels aren’t indestructible, they are extremely durable. That said, there are some ways that you can extend solar panel lifespan.
Solar panels require maintenance
Solar panel systems require very little maintenance, but routine inspections and upkeep are necessary. This ensures that your green energy system is in good repair and functioning at maximum efficiency.
Many solar providers offer an operations and maintenance (O&M) agreement to do just that, which makes things even easier on the owner.
Operations and maintenance contracts
O&M contracts typically include an annual system checkup for your solar energy system components, including the solar panels, the racking and mounting infrastructure, the electrical system and wiring components, and the inverter.
If you also have battery energy storage as a part of your solar system, commonly called a solar plus storage system, that will be inspected as well.
During the annual inspection, your provider will check and repair damage to your solar system’s components that may have been caused by normal wear and tear or extreme weather, like high winds or hail.
Most O&M agreements also include a quick survey of your entire solar installation, which can alert you to new or increased shading by overgrown vegetation, tree branches or even new construction around your installation.
Annual maintenance is important not only to maintaining panel efficiency but because it allows you to catch potential issues with your solar system before they become a crisis.
Monitoring
In addition to regular maintenance, many solar providers, like Velo Solar, offer virtual monitoring services as a part of their annual O&M packages.
Real-time monitoring solutions allow your provider to manage the day-to-day operations of your solar panel system. The software sends an alert when it detects an issue with your solar system, often before you know anything is going on.
If, for example, the software detects a drop in efficiency or production in the aftermath of a storm, the provider can send an expert out to diagnose the issue.
Having your provider monitor the performance of your system is another way to quickly identify potential issues, including damage to your solar panels, before small problems become a crisis.
Other solar system components
While solar panels last on average 30 years or more, the other components of your system will likely need attention before that.
As noted above, if you have an O&M agreement with your solar provider, they’ll inspect and monitor things like the solar inverter, batteries, and racking system. Should an issue arise and a component need to be repaired or replaced, they can alert you before there’s an equipment failure.
Solar Inverters
Every solar system includes an inverter that converts the direct current (DC) electricity generated by your solar system to the alternating current (AC) electricity used to power your facility and its equipment. Larger solar panel systems may have more than one inverter.
You’ll find that solar inverters typically last 10 to 15 years before they need to be replaced. This is largely due to the fact that they’re continually at work, converting the DC electricity from your solar panels into something that your business can use.
Solar batteries
The lifespan of your solar battery is largely dependent on the type of battery you’re using.
Solar batteries are a type of electrochemical battery; they store and release energy through a chemical reaction. The most common types of electrochemical batteries are lead-acid, nickel cadmium (NICd), nickel metal hydride (NiMH), and lithium ion (Li-ion).
Lithium ion batteries, which are typically used in solar applications, typically have a lifespan of 15-30 years, depending on the model and factors like the number of times they’re charged and discharged, environmental conditions, and how well they’re maintained.
The racking system
The racking system should be inspected on an annual basis to ensure you have a solid foundation supporting your solar array. The weather and elements can cause damage that you’ll want to have repaired.
When Do Solar Panels Need to be Replaced?
Some of the first questions a reputable solar provider will ask when you kick off a solar project relate to your solar energy goals.
Are you looking to install solar to reduce your electric bills by replacing grid electricity with your own solar power produced on-site?
Perhaps you’re looking to reduce your carbon footprint by using more clean, sustainable energy.
Maybe you’re looking to improve your resilience in case of an extended power outage.
Whether your motivation is cost, sustainability, resilience, or all three, you’ll know it’s time to replace your solar panels when they are no longer producing enough electricity to achieve your solar energy goals.
The bottom line is that working with a reputable solar provider like Velo Solar can maximize your solar power output for decades.
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