Solar Panel Lifespan: How Long Will a Solar Project Last

Topic: solar projects Read Time: 7 mins
Landowner type:
Independent landowners | Institutional landowners
Energy: Solar
Back to Blog

If you’re a landowner looking to host a project on your land, you might be wondering what the average solar panel lifespan is. After all, you’ll want to rake in passive income for as long as possible, and that’s largely down to how these panels hold up over time.

Most solar panel manufacturers will outline an expected lifespan for their products that you can rely on with relative certainty. But realistically, it’s hard to tell precisely how long the average panel will last. And before you can get an accurate figure, you need to consider everything from panel types to weather factors and long-term irradiation damage.

To help you out, we’ve pulled together an in-depth guide on average solar panel lifespans (and how you can extend them). We’ll even give you a quick low-down on the types of solar panels available and which option wins out on longevity.

Solar panels usually last for more than 25 years, and many manufacturers offer warranties of 25-30 years. With proper maintenance and care, monocrystalline panels can last as long as 35 years.

Technically, the panels continue to work after their expected lifespan. However, they slow down considerably and produce electricity at a lower rate. While you might tolerate this on residential properties, the lower efficiency over time means they’re no longer viable for large-scale projects chasing profit.

So, while it’s uncommon for a solar panel to stop producing energy completely, the degradation rate may be significant enough that your developer will need to replace the panels entirely. As this degradation is a natural consequence of sunlight exposure, it’s something that any project will need to tackle during its lifetime.

Technicians expecting a solar panel

As a rule, monocrystalline panels tend to last longer than polycrystalline panels. That’s because monocrystalline panels are made up of single silicon sheets, while polycrystalline panels are made of multiple silicon crystals. The fragmented layout of polycrystalline panels means they have more failure points that might crop up during their lifetime.

Solar panels usually reach a breakeven point around 6 to 10 years after installation for domestic properties. For large-scale projects, the average ROI is between 10 and 20%. If the panels produce energy at a high level for the project’s lifetime, you can make a considerable amount once the initial investment is paid off.

While solar panels don’t usually stop working at the end of their usable life, they seriously decline in efficiency. This can be down to everything from mechanical stress on the materials to humidity, weather damage, and long-term exposure to strong sunlight.

This gradual loss in efficiency usually occurs at around 0.5% a year. So, if we take 25 years as the average usable length of solar farm panels, they’ll be operating at around 87.5% of their original capacity. Although you can’t really avoid this degradation, let’s examine the factors that can affect solar panel lifespan.

A photo collage showing the three popular types of solar panels

One of the biggest factors affecting solar panel lifespan is the type of solar panel chosen for a project.

Just for a bit of context, the main three types of solar panels used in projects across the UK are:

  1. Monocrystalline
  2. Polycrystalline
  3. Thin-film

Although other types of solar panels are available, they are typically not durable or efficient enough for most large-scale sites.

Monocrystalline is the most common panel type that developers choose for solar farms. However, some developers will choose cheaper polycrystalline panels depending on their cost-benefit analysis. 

Occasionally, purchasing more polycrystalline panels (to reach the expected efficiency of a smaller number of monocrystalline panels) is more cost-effective. However, monocrystalline panels always have the upper hand when it comes to longevity.

While both types of panels typically come with a 25-year warranty at minimum, monocrystalline panels can remain efficient for up to 40 years. Polycrystalline panels can push to 35 years, but they’re typically at the end of their operational life before this stage. So, it’s worth considering these factors before settling on the solar panels for your project.

A solar panel covered with snow

We’ve touched on this point throughout the article, but age-related degradation is a serious consideration for any solar panel. You’ll expose your solar panels to many external factors during a project’s life.

These include:

  • Humidity
  • Strong winds
  • Snow
  • Sleet
  • Hail

Snow, sleet, and hail have the potential to seriously damage the glass covering the silicon panels. However, snow can also prevent sunshine from reaching the panels (unless cleaned and maintained regularly). Aside from apparent damage from fast-moving hail, the weather factors above can also lead to frame corrosion. This causes the crystalline silicon inside the panels to harden over time, affecting sunlight absorption.

It might sound bizarre (considering solar panels are naturally exposed to light), but sunlight can degrade the panels. This only happens at an extreme rate when the solar panels are FIRST EXPOSED to sunlight – so, when they’re first set up. However, past this point, the solar panels will degrade at a rate between 0.8% and 0.9

While we’ve discussed weather factors that affect solar panel lifespans, heat and voltage can also shorten their usable life.

When you expose solar panels to high temperatures, potential-induced degradation occurs. This process happens when there’s a high potential difference between the semiconductor material (AKA: silicon in the cell) and the glass frame. During this degradation process, negative ions flow from the aluminium frame and positive ions head to the cell’s surface. These degrade the cell and reduce its photovoltaic effect. The loss of power can be significant, and the effects become even more noticeable if the loss continues for several years.

Now that we’ve discussed what can potentially degrade your panels, let’s discuss how you can PROLONG their lifespan.

A professional cleaning a solar panel's surface

One of the main ways to boost your solar panel lifespan is by maintaining them and checking for any chips or breaks in the glass.

If your panels don’t undergo regular maintenance, you’re more likely to miss underlying issues that could reduce the lifespan of your panels. If nothing else, adequately cleaning your panels will keep them as efficient and productive as possible.

You’ll need to check for the buildup of dust, leaves, pollen, and bird droppings. Any of these obstructions can reduce your solar farm’s efficiency because they cover the glass that protects the silicon sheets.

If you notice your panels’ performance has dipped, you can hire a professional cleaner. But you can also carry out regular checks and trim back vegetation that may be shading them. Speaking of vegetation, you’ll want to trim any low-hanging branches that might physically damage the panels themselves.

Oh, and it’s always worth sweeping your site after any extreme weather. Storm damage can seriously impact your site’s profitability and shorten the lifespan of even the hardiest panels.

It probably goes without saying, but properly installed solar panels have a serious boost in lifespan. You’ll first want to check how the panel is installed. Correct racking can prolong the lifespan of your panels as it reduces the chance of slipping, damage, or obstructions that might damage the glass.

While you’ll want to clean and install your panels carefully, the average solar farm consists of more than just panels. So, it’s essential to check the panel outputs and metres regularly. This is usually done by the inverters themselves or through a dedicated monitoring system.

If the output is registering significantly less than expected for that time of year, you’ll want to find out why that is – and fast. But if you CAN pinpoint the problem, you can get your panels fixed and increase their expected lifespan (without losing much income in the process).

As you can see, a LOT goes into determining the solar panel lifespan across a site. From monitoring and regular cleaning to weather considerations and panel types, the sheer number of potential factors makes it hard to know precisely how long a panel will last.

However, you can usually rest assured that most panels will last for upwards of 25 years, giving you plenty of time to reap the rewards of leasing your land. And if the panels do degrade to the point of replacement, your developer will bear the brunt of that cost. What’s not to like?

Get in touch, we’d love to hear from you if you want to install a solar project on your land. We can confidently guide you through the process, help you secure the best deal possible on your lease agreement and give you a hassle-free introduction to renewable energy.

How likely is your land to get planning permission for a solar project?

Enter your details to find out.