How long do solar panels last? A lifespan guide

Investing in renewable energy sources can feel like a big commitment, so it’s only natural that you want to know your investment will last. After all, part of being sustainable is avoiding throwaway culture. And with the rise in energy bills, renewable energy sources provide a way to save money long-term, as well as reduce carbon emissions. Solar panels can produce more energy in a year than you need to fuel your home, allowing you to sell the excess back to the grid. For example, while the average UK household uses 3,100kWh of energy per year, the amount of energy produced by solar power in the north of England can be up to 4,158.45kWh.

The lifespan of solar panels

How long solar panels last depends on how they were made, with monocrystalline models generally lasting longer, for over 30 years. Many manufacturers offer warranties that protect the solar panels for at least half of their expected lifespan, with a guarantee that performance won’t drop below a specified level during that time.

There are two main types of solar panel: monocrystalline and polycrystalline. They both work in the same way, but the way they’re made is different. The silicon which makes the cells for monocrystalline solar panels is shaped into bars, then cut into wafers. The silicon which makes the cells for polycrystalline solar panels is melted together into wafers. Monocrystalline solar panels last around five years longer than their polycrystalline counterparts.

It’s worth noting that the reliability and longevity of solar panels has grown considerably over the years, and just because a solar panel no longer has a warranty or is older than its predicted lifespan, doesn’t mean it won’t still produce energy. It may not produce as much as it did at the peak of its life, but will still work if cared for appropriately.

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What is the warranty of solar panels?

The warranty is different depending on the manufacturer and model, but is normally based on a number of years combined with a percentage of production. The most common example is a guarantee of 90% production for the first 10 years, then 80% production for the next 25 years. Some solar panels can still run at 80% production beyond this timeframe.

Solar panel performance over time

The performance of solar panels fades over time, with the panels producing less energy than they did at the start of their lives. This is known as the degradation rate. Luckily, the degradation rate has improved as solar panel technology has developed, and is currently around 0.2-0.5% per year.

What causes solar panel degradation?

The most common cause of solar panel degradation is general wear and tear from things such as:

• Bird droppings
• Dirt
• Dust
• High temperatures
• High winds
• Leaves
• Pollen
• Snow

This accumulation of debris is known as soiling and it reduces the amount of energy the panels can absorb. In many cases, its impact can be reduced with careful maintenance.

Solar panel maintenance

Solar panels are designed to withstand all sorts of weather conditions. That said, taking care of your solar panels can increase their lifespan (and the amount of time they provide you and your household with energy). You can look after them by:

• Cleaning the surface of the panels regularly to remove any debris, using a soft brush to sweep it away. More stubborn marks can be washed using warm water and a cloth. It’s best to do this in the morning or evening, as they can get hot during the day when it’s warmest.
• Checking them regularly for any signs of damage, so it can be fixed as soon as possible.
• Reaching out to professionals if your solar panels need more than a good clean, you notice anything unusual in your utility bills, or the space under the panels needs cleaning (the wiring makes it dangerous to do this yourself).

What happens at the end of a solar panel’s life?

As solar panels become more common and the earlier models start to reach the end of their lifespans, it’s likely that conversation will turn to how they can be disposed of responsibly. Understandably, given the ethos of renewables, recycling is the preferred option over simply sending solar panels to landfill sites. When solar panels are recycled, their components, including glass and metals, get separated out so they can be made into something new. The solar industry is working with recyclers to make this process as efficient as possible.