RNE has an article on water free solar power panel cleaning in the desert - Saudi solar robot cleans desert PV panels – water free.
A United Arab Emirates company spun out of the nation’s renewed focus on renewable energy has come up with a simple solar panel cleaner designed to clean every panel in its coverage area each day.
The NOMAD Desert Solar has released the NOMADD which stands for The NO-water Mechanical Automated Dusting Device which was developed at the King Abdullah University for Science and Technology, (KAUST) near Jeddah, Saudi Arabia. The device has been kept simple and cost effective adding just 10c/Watt to the capital cost of a solar system to have the capacity to clean it daily.
In the past most solar systems (solar thermal and photovoltaic) have been washed by teams that drive around arrays in dedicated washing trucks armed with giant scrubbers on extension arms using significant amounts of water. Both labour and water are resources that often aren’t readily or cheaply available in locations where large solar arrays are installed. Therefore cleaning regimes have usually been on a fortnightly or monthly basis or are adapted to take into account seasonal operational and conditional requirements.
Automatic cleaners use very little water relying more on scrubbing action to get a perfect clean. Torresol’s energy’s Gemasolar plant near Seville in Spain uses the company’s smaller HECTOR robotic cleaners for its heliostat mirrors.
The difference between the NOMADD approach is that instead of cleaning during nights and aiming to clean each mirror/ panel every 7 or 14 days the NOMADD approach for North Africa and the middle east is about cleaning every panel as much as once a day, cleaning day and night, while Torresol’s approach uses a tiny bit of water the NOMADD approach uses no water at all.