The ideal environment for utility-scale solar photovoltaic (PV) installations is a location with an abundance of sun and space for ground-mounted arrays — in other words, desert areas. While deserts have around 300 days of full sun each year for prime solar energy production, these regions also pose unique challenges due to the combination of frequent sandstorms and minimal rainfall.
These harsh environmental conditions result in significant panel soiling, thus reducing the overall energy generation potential from a solar PV system. According to the International Journal of Sustainable Energy, energy production loss caused by soiling can reach up to 40 percent, significantly impacting the rate of return on the owner’s investment.
The good news here is that if solar panels are cleaned daily, energy losses are essentially eliminated; the bad news is that traditional cleaning methods come with a high cost — both economic and environmental.
The most common method to clean large-scale PV installations involves trucking large quantities of water to the site for a manual hose-and-squeegee session. This can be an expensive, time-intensive process in any environment, and in a dry desert setting, costs are off the charts. An average 100 MW desert-sited solar plant, for example, will require approximately 56,000,000 gallons of water over its project lifetime. The associated long-term costs are significant — up to $70 million for a 100 MW project in the Southwestern United States considering both the cleaning cost and production losses in between the cleanings.
In many countries, labor and water demands make the cleaning process a cost-intensive add-on that hinders the development and deployment of solar plants. For example, India’s tremendous solar expansion plans could be delayed and less impactful if water-intense solar maintenance is not solved. This leaves system owners to juggle a double-edged sword: suffer the financial consequences of water-based cleaning or lose revenue with a soiled, underperforming plant.
With this in mind, it’s no wonder project developers are searching cost-effective, water-free alternatives to traditional panel cleaning.
The Rise of Robotic, Water-Free Cleaning
New technology developments are offering plant owners an economically feasible, environmentally friendly cleaning option. Using nothing more than microfiber cloths, controlled airflow and gravity, advanced robotic systems are proven to remove 99 percent of dust from panels each day, without a single drop of water. To further optimize operations costs, robotic units are designed to be self-sustaining, powered by their own small solar panels. With the support of a web-based monitoring and control portal, these sophisticated systems also allow site managers to make better-informed plant management decisions based on real-time and forecasted weather information.