The Hidden Costs of Manual Solar Panel Cleaning

How traditional solar panel cleaning leaves value on the table, or rather, on the panels.

If you are a solar energy system owner, cleaning your solar panels regularly is a no-brainer. Dirt, air pollution, even bird droppings can settle on your panels, preventing the panels from producing energy at maximum capacity. Simply put, panels + dirt = lower energy production. And lower energy production directly translates to lower energy revenue (or savings) for you, whether you consume the electricity directly or provide it to another entity. So, it’s important to keep your panels as clean as possible. Easily solved, right? Not quite. 

Did you know that even if you clean your panels regularly, you’re still likely leaving tens of thousands of dollars on the table every year

The reason is that dirt lands on your solar panels every day, keeping the sun from reaching the panels. The amount of production lost over time due to this dirt is called the “soiling rate”. If this rate is high enough, manual cleaning doesn't have a large impact on improving production and project owners pay the price.

Traditional cleaning = Lost revenue

Traditional manual solar cleaning techniques drag down solar owners’ long-term revenue. How? Every day, dirt and other particles settle on the surface of your solar panels, which keeps the sun’s rays from reaching the panels. The production lost as a result is known as the soiling rate. And if the soiling rate is high enough, even regular manual cleanings don’t stand a chance to significantly improve production - and solar owners pay the price.

Not only do cleaning fees add up over time, but you also lose money from the reduced production of soiled panels between each cleaning. While you may be able to tolerate lower production due to soiling losses for a year or two, the reality is that you are missing out on this added revenue every single year for the entire lifetime of the system. That’s 20 years or more with lost profits. Below, we take a look at an example to understand just how much money solar owners are leaving on the table - or rather, on their panels.  

Lost revenue grows exponentially as soiling increases

In California’s Central Valley, average daily soiling loss ranges from 0.5% in the winter months up to 1.5% in the fall months. This translates to an average of nearly 1% production loss added per day. Each additional day means even more losses from soiling.

Average Daily Soiling Losses per Month in the Central Valley

By this estimate, you’ll reach 7% cumulative panel soiling over the course of a week, amounting to almost $150 in lost revenue (or value) for a 1 megawatt (MW) system. Your lost revenue continues to increase exponentially as more time goes by and your soiling levels accumulate on your panels. 

Revenue Loss by Number of Days After Manual Cleaning in the Central Valley

Cleaning fees are an added long-term cost

On top of this, cleaning fees create additional annual costs. Regular manual panel cleaning services can range from roughly $5,000 to upwards of $75,000 per year, depending on cleaning frequency. When combined with production losses due to soiling, a 1 MW system cleaned weekly at 50 cents per panel can cost you about $84,000 every year… for 20 years or more. Ouch!

Switching from weekly to monthly or even quarterly cleanings can lower your annual spend on cleaning fees, but keep in mind that your production losses also increase as your cleaning frequency decreases.

This means that no matter how you shake it, traditional solar panel cleaning will continue to drag down your long-term solar profits.

Revenue Loss with Manual Solar Cleaning by Cleaning Frequency

It’s time to come clean

You may be asking yourself, why isn’t this lost revenue commonly discussed amongst solar developers and landowners? Until recently, manual panel cleaning was the only option, so solar owners had to make their peace with the long-term costs and production losses that come with cleaning their systems, not to mention the occasional manual cleaning that gets lost by heavy wind the next day. What a loss to pay for a cleaning only to see your panels dirty again.

The great news is that there’s no need to settle anymore: Automated panel cleaning systems like RST Nightwash™ allows you to clean every day, minimizing losses and maximizing production. Plus, you can avoid manual cleaning costs for good. By switching to an automated cleaning system that can be paid off in just a couple of years, you can finally stop paying for regular cleanings and maximize production - and therefore profit - from your solar panels, for good.

Simply put, keep your panels clean all the time to maximize production and value for your system.

Want to learn more about how to come clean and escape long-term solar panel cleaning costs? Reach out to RST CleanTech for a complimentary assessment.


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