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.
Case Study
Arava Power, a leading solar developer in Israel, has seen firsthand the significant energy production improvements enabled by this technology. For its 5 MW Ketura Sun plant in the Arava Desert, the company initially opted for manual cleanings 10 times per year, each requiring approximately five days of work. During this time, laborers and equipment interfered with system output, and occasionally damaged the panels themselves.
In 2013, Arava made the transition to nightly cleanings with a robotic, water-free cleaning solution. With the support of nearly 100 energy-independent robots, Ketura Sun now sees a significant uplift in electricity production than before, and achieved full payback after just 18 months.
Yanir Aloush, vice president of operations for Arava Power, noted the company is now benefitting from “less guesswork about when to clean, less downtime since there’s no need for on-site cleaning crews less external personnel on the ground,” adding that the technology “has changed the way we run the Ketura Sun field.”
For utility-scale solar projects in harsh desert climates, water-free robotic cleaning technologies are the most cost-effective, energy efficient and sustainable cleaning options available on the market. Not only does this innovative solution enable PV plants to be more cost competitive with fossil fuel-based power generation, it also goes above and beyond to conserve precious water resources before it’s too late. Water-free robotic cleaning technologies will change the way utility scale solar plants operate.
Eran Meller is the CEO and co-founder of Ecoppia, a designer and producer of photovoltaic panel cleaning solutions. He has also served as a CFO for organizations such as Telmap, X-Tip and Info-X. Meller has also worked with the International Finance Corporation (IFC), the private arm of the World Bank Group.
