Solar PV System Cleaning: A Comprehensive Guide
We are often asked questions about cleaning solar panels, such as "Do I need to clean my solar panels?", "Should I clean them every year?", and "How often should I clean them?". After all, solar panels are likely to accumulate dirt and residue over their lifespan, right?
The answer to this question is that, at some point in their lifetime, it's probable but not necessarily required. The truth is, the need for cleaning varies depending on the environment you live in. Some panels will require more frequent cleaning than others, while some may never need it. Contrary to what some solar cleaning companies claim, there is generally no need to clean them annually.
Our general rule of thumb for customers is to review the panels on an adhoc basis. If they appear grimy, dull, or have a noticeable sheen, it may be worth cleaning them. If your system has been underperforming or you've noticed a decline compared to the same month last year or over the past couple of years, a clean may help restore their performance.
Geographical location and local circumstances
Various factors can contribute to the need for cleaning. For example, if your system is close to trees, sap can travel onto the panels and living near the ocean can result in salt residue buildup. You may also have pests using your solar PV system as a toilet or you may live near a busy road where heavy goods vehicles pass through. All of these circumstances can lead to a residue buildup that would require cleaning.
On the bright side, PV panels are designed to minimise the need for cleaning and with most panels being angled, this facilitates self-cleaning when it rains. This though, does highlight flat roof installations, which can have more of a build up of dirt due to the angle of the flat roof array having been designed at a 5-10 degree angle.
If you decide to have your system cleaned, we suggest monitoring its performance before and after the cleaning to assess any noticeable difference. While you may want to clean them for aesthetic reasons, if the goal is solely to improve system performance, it's worth calculating whether the increase in electricity generation after cleaning covers the cost of the cleaning itself.
Factors contributing to cleaning needs:
Rainfall and Dust: In areas with regular rainfall, precipitation often adequately cleans the solar panels. However, if you live in a particularly dusty area or one prone to heavy pollen, bird droppings, or leaves, these substances can accumulate over time and may not be adequately cleaned by rain alone. In such cases, periodic cleaning could be beneficial to maintain optimal performance. The SolarandBatteryCompany.com recommends the installation of bird protection mesh to deter pests from making your system a nice perch or home.
Angle of Installation: The angle at which your solar panels are installed also plays a role. Panels installed at a steeper angle are generally more self-cleaning as debris can slide off more easily with gravity and water flow. If your panels are installed at a shallow angle, they might retain more dust and debris, necessitating more frequent cleaning.
Impact on Performance: A layer of dust or debris on your solar panels can reduce their electricity output by blocking sunlight. While this impact is usually minimal (often only a few percent), it can add up over time, especially for larger systems or in particularly dusty environments. Cleaning can restore the panels to their maximum output.
Given these factors, it's recommended that you monitor your system's performance over time. If you notice a significant drop in output that doesn't align with the seasonal variation in sunlight, it could be
a sign that your panels need cleaning.
Consider the risk
Now, if you've decided that your panels do need cleaning, here's a word of caution: prioritise safety. Solar panel cleaning typically involves accessing the roof, which can be dangerous. While there are safe ways to clean solar panels, such as using a long-handled brush or hiring a professional cleaning service, it's essential to consider whether the potential increase in output is worth the associated risk and cost. If you're not comfortable doing it yourself, hiring a professional service may be the best course of action.
Conclusion
In conclusion, while solar PV systems generally don't require frequent cleaning there could be times when it is required, and monitoring your system performance and comparing it to previous years is the best way to judge it.