Engineering Challenge: Design a Waterless Solar Panel Cleaner

A sustainable energy company is looking for design ideas for an autonomous PV panel cleaning system.

When solar panels get dirty, energy production can decrease by 5 percent or more, depending on the weather. If you have a rooftop photovoltaic (PV) array, most solar professionals will tell you that you don’t need to wash the panels—the rain takes care of it for you. That’s true in most places that get significant precipitation at least once a month or so. But many utility-scale solar farms are located in arid climates, which presents two problems: more dust and less rainfall to remove it. A study published in the International Journal of Sustainable Energy found that one gram of dirt per square meter can decrease a panel’s output by more than 30 percent, which is why commercial PV farms often employ some form of cleaning. Most PV experts suggest cleaning solar panels with water and perhaps a mild soap or detergent, which can present a formidable problem: how do we get water to clean panels located in the desert?

Cleaning solar panels without water. (Image courtesy of Iberdrola.)

Cleaning solar panels without water. (Image courtesy of Iberdrola.)

Iberdrola, a European company that specializes in sustainable energy, launched a competition for startup businesses and budding entrepreneurs: design a cost-effective, water-free system for cleaning solar panels. (How hard can that be, right?) What’s in it for you? This:

The design contest launched by Iberdrola. (Image courtesy of Iberdrola.)

The design contest launched by Iberdrola. (Image courtesy of Iberdrola.)

The Challenge

Okay, engineers, here’s the deal: Iberdrola is looking for a PV cleaning system that uses very little water (ideally, none at all), works with fixed-tilt or single-axis tracking arrays in multiple rows, is fully autonomous or remote controlled, and doesn’t use energy from the PV array itself. More details are available on the project website.

A New Engineering Design Model for Business?

Lately, I’ve seen a number of these “competitions” where a company asks people to submit designs, with the winner getting the contract. I have mixed feelings about this trend. On the one hand, it seems like these businesses are simply asking engineers to do the preliminary R&D for free, while the company reaps the benefits. On the other hand, it could be an opportunity for upstart companies, consulting engineers, and even students to gain some valuable experience. Engineering educators could encourage their students to enter competitions like this in problem-based learning (PBL) assignments, senior design projects, or even extracurricular activities. In that respect, it would serve as an internship with added incentive: if your design is chosen, you actually get paid! Either way, it’s a learning experience.


Need some ideas to get you started? Here you go:

●       First Solar’s recommendations for cleaning its PV panels

●       A commercially-available robotic solar panel cleaning system

●       An unsuccessful Kickstarter campaign to produce a Roomba-like PV panel cleaner

●       The National Renewable Energy Laboratory (NREL) Best Practices for solar farm operation and maintenance (including cleaning)

●       ProjectBoard at

Submissions will be accepted through October 18, 2019. Good luck, and let us know if you win!


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