Do solar panels lose efficiency over time?

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Solar cells, and therefore panels containing cells by design degrade over the years. Photovoltaic cell degradation occurs as the semiconductor material ages and becomes less efficient at converting sunlight into energy.

The encapsulant protecting PV cells can deteriorate from environmental stresses, affecting efficiency. Light-induced degradation from initial exposure to sunlight also reduces electron movement within the cells and impacts performance.

Solar panels can also lose efficiency over time due to physical, environmental, and chemical factors. Exposure to elements like heat, cold, wind, rain, hail, and storms can create stress on the panels, causing potential micro cracks in panel cells and that can lead to a performance reduction in rare cases. 

Despite these factors, quality solar panels are designed to be durable, and their performance warranties typically cover a gradual loss of efficiency over the years, with performance warranted often at being around 90% of their original capacity after 25 years of operation.

Will my solar panels lose efficiency over their lifespan?

Solar panels are well-known for generating clean, renewable energy from sunshine. However, as with any technology, they are prone to wear and tear and can lose efficiency with time. Solar panels lose efficiency for various reasons, including physical, environmental, and chemical issues. This post will examine these reasons and explain how father time leads to the progressive deterioration of solar panel’s performance.

In saying this, quality solar panels are tested extensively and designed to be as durable as possible, with a wide range of tests undertaken to ensure they can handle the extreme conditions they are exposed to.

All solar panels also have a performance warranty that is included with them, and for quality products, they are covered for 98% of their initial output in the first year and as low as 0.3% to 0.5% further degradation or loss of efficiency per year onwards up to 25 years. This means after 25 years quality panels can still produce more than 90% of their initial output. Cheap solar panels on the other hand deteriorate faster and could have lost more than 10% more efficiency over their lifespan than quality solar panels. 

Why do solar panels lose efficiency?

Solar panels are installed on the roofs of houses and businesses. As a result. they are constantly exposed to the elements and UV, day in and day out, for years. The heat of the day and summer, the cold of the night in winter, winds, rain, hail, storms, extreme heat etc, create stress on the solar panel cells. 

Dramatic temperature changes also can cause deterioration to the cell surface over time which can lead to some loss in power.

Phenomena include light-induced degradation, which is the initial and ongoing impact of light hitting the solar cells, which reduces the movement of the electrons within the cell, and reduces performance when the solar panels are first installed and exposed to light from what they were tested at in a factory. And just like a battery in your phone over time solar panel performance decreases. 

solar panel manufacturing

Cell degradation

Photovoltaic cells, which convert sunlight into electricity, are at the heart of a solar panel. Frequent exposure to sunlight causes the cells to deteriorate over time. The deterioration of the semiconductor material within the cells is a crucial factor. Exposure to ultraviolet (UV) radiation, temperature variations, and moisture can all contribute to this degradation. As the material ages, it becomes less efficient in converting sunlight into energy, resulting in lower overall solar panel performance.

Encapsulation issues

An encapsulant, such as ethylene-vinyl acetate (EVA), encapsulates the PV cells and protects them from environmental variables in solar panels. However, exposure to heat, UV radiation, moisture, and other environmental stresses can cause the encapsulant to deteriorate over time. This degradation can reduce the solar panel’s efficiency because the cells are no longer effectively shielded.

Potential induced degradation

Another issue that can affect the performance of solar panels is potential-induced degradation. When solar panels are connected in long strings or series of panels, the solar panels at the end of the series with the highest voltage can be affected by the conductivity of the aluminium frame, which can lead to a loss in the performance of the cells in the panel.

Old age

Solar panels are made up of a variety of electrical components, such as connectors, cables, and inverters. Due to exposure to environmental conditions, these components might degrade over time, resulting in higher resistance and lower electrical performance.

In summary

While there are several potential risks to the performance of solar panels over time, quality solar manufacturers understand these. They are able to minimise the performance lost from these within the manufacture of the panels. While solar panels do lose efficiency over time, just as part of the technology, the fact that quality solar panels could still perform at around 90% of their original capacity after 25 years of operation demonstrates how durable and stable the performance of quality solar panels is. Cheap solar on the other hand, unfortunately, its performance dies in a ditch. 

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