How to clean solar panels without water?
Solar panels are expected to play an important role in the global energy transition. Solar is supposed to generate ten percent of global electricity by 2030, and much of these solar panels is likely to be located in desert areas, where sunlight is abundant. And there is a problem: dust. Accumulation of dust on solar panels or mirrors can reduce the output of photovoltaic panels by as much as 30 percent in just one month. Therefore, they must be cleaned regularly. And that is another problem The warmer the climate, the less water is available. According to Prof. Kripa Varanasi, professor of Mechanical Engineering at the Massachusetts Institute of Technology (MIT), cleaning solar panels currently is estimated to use about 40 billion litres of water per year – enough to supply drinking water for up to two million people. Attempts at waterless cleaning are labor intensive and tend to cause irreversible scratching of the surfaces, which also reduces efficiency.
Now, a team of researchers from MIT led by Prof. Varanasi has devised a way of automatically cleaning solar panels, or the mirrors of solar thermal plants, in a waterless, no-contact system that could significantly reduce the dust problem, they say.
The new system uses electrostatic repulsion to cause dust particles to detach and virtually leap off the panel’s surface, without the need for water or brushes. To activate the system, a simple electrode passes just above the solar panel’s surface, imparting an electrical charge to the dust particles, which are then repelled by a charge applied to the panel itself. The system can be operated automatically using a simple electric motor and guide rails along the side of the panel.
It has since been published in Science Advances under the title ‘Electrostatic dust removal using adsorbed moisture–assisted charge induction for sustainable operation of solar panels’.
