key solar panel metrics

How long will my solar panels last?

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One of the most common questions we hear from homeowners considering a solar panel installation is, “how long do solar panels last?” It’s hard to make sense of the upfront cost of going solar without knowing how long you can expect your rooftop panels to produce ample energy. Your solar panels will be able to offset your electricity use for decades, but it is also important to understand industry projections and degradation rate. 

How long do solar panels last?

As a general solar industry rule of thumb, solar panels last 25-30 years. However, this doesn’t mean that they stop producing electricity after 25 years – it just means that energy production has declined by what manufacturers consider a significant amount. Solar panels can continue to work for many decades, given they aren’t physically damaged by wind, debris, or any other factors. This is primarily because solar panels don’t have any moving parts – they rarely break from within and are only ever damaged by outside forces like poor racking or bad weather.

Solar panel degradation rate

A 2012 study by the National Renewable Energy Laboratory (NREL) found that, on average, solar panel output falls by 0.8 percent each year. This rate of decline is called solar panel degradation rate. Though this rate of decline metric will vary depending on which panel brand you buy, premium manufacturers like SunPower offer degradation rates as low as 0.3%. Solar panel degradation rate is constantly improving as solar panel technology improves, and degradation rates below 1% are very common throughout the industry. In the years since this 2012 study was conducted, more efficient technologies have been developed and many newer panels have just a 0.5 percent yearly decline in energy output.

What does degradation rate mean exactly? For the above example, a 0.8% degradation rate means that in year two, your panels will operate at 99.2 percent of their original output; by the end of their 25-year “useful lifespan,” they will still be operating at 82.5%.A slightly more durable panel with a degradation rate of 0.5% will likely produce around 87.5% as much electricity as it did when it was first installed. To determine the projected output of your solar panels after a certain number of years, you can simply multiply the degradation rate by the number of years you are interested in and subtract that number from 100%.

Solar panels also come with a few different warranties that can give you a sense of just how long you can expect your solar panel’s lifespan to be. Manufacturers will offer both an equipment warranty, to certify against manufacturing defects, and a performance warranty, to guarantee that your panels will produce a certain amount of electricity. Your solar panel’s performance warranty, which typically lasts 25 years, can give you a better sense of how much electricity to expect from your solar panel system over time.

You don’t need to worry about the carbon footprint of your solar panels, either. The 25 to 30 year lifespan of a solar panel is significantly longer than its “energy payback time,” or EPBT. EPBT is the amount of time it takes for a solar panel to produce enough clean electricity to “pay back” the energy that was used to manufacture it in the first place. A 2010 analysis from Brookhaven National Laboratory found that the EPBT of a solar panel is just six months – a number that has surely fallen in the past six years as panel manufacturing becomes more efficient.

Can you make solar panels last longer?

In general, solar panels are extremely durable. Most manufacturers test their panels to confirm that they can withstand high winds and heavy snow loads, and many solar panels are specifically tested to ensure that they can withstand falling hail. Additionally, solar energy systems don’t usually have moving parts, and they require little to no maintenance.

The best way to keep your solar panels working long-term is to work with a reputable installer that offers solid customer service.  It’s also important to purchase solar panels that have robust warranties – many panel manufacturers offer 10 to 12-year equipment warranties for their panels that cover defects and environmental damages, as well as production warranties usually lasting around 25 years that guarantee your panels will produce above a certain amount of energy for your home.

Nevertheless, keeping your solar panel system well maintained can lead to a lower degradation rate each year and can promise longer panel performance. Here are a few actions you can take to make your solar panels last longer:

Regularly get your panels checked by your installer or service provider

The best way to ensure your solar panels last a long time is to have your installer or operations and maintenance (O&M) provider regularly examine your solar energy system. A regular examination can reveal potential issues like loose racking, exposed wires, and other areas of concern. It is important to have a professional check up on your panels instead of doing it yourself because you can void your panel warranty if you end up scratching or otherwise damaging the panels on your roof.

An inspection of your solar panels may also include an inspection of the other equipment involved in a solar installation, namely your solar inverters and roof racking system. A typical central inverter for a PV installation will last between 10 and 15 years and thus will need to be replaced at some point during the lifetime of your solar panels. However, micro inverters are a new and popular alternative to central inverters and generally offer the same lifespan as their solar panel counterparts – 25 years. When it comes to racking, it is always essential to make sure that your panels are securely mounted to your roof so they don’t become loose and move around or fall off entirely.

Keep your panels clear of debris and other damaging materials

When you first install your solar panels, your installer will make sure that there are no large trees that could cast a shade or drop branches on your panels. As long as you can avoid physical damage to your solar panels, they will continue to produce energy for many years, possibly far beyond the 25 to 30 year “lifetime” of typical solar panels. You can even buy specialty products to prevent specific types of physical damage to your panels. For example, solar panel critter guards can keep animals like squirrels and birds from nesting under your panels, which can cause panel and wire damage over time.

Finding a sustainable solar solution for your home is easy 

Going solar is an investment in the earth’s future that can also save you money by reducing your monthly electric bills. By thoroughly researching solar equipment manufacturers and working with solar installer that offers the products you want, you can ensure that your solar panel system is as sustainable as possible. Compare solar quotes side-by-side the EnergySage Solar Marketplace to find the right combination of sustainable products, easy financing options, and a well-reviewed installer for your home’s renewable energy needs. All of our installers are qualified and pre-vetted so you can have the peace of mind that you are working with a licensed solar professional.


This post originally appeared on Mother Earth News.





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