A photovoltaic panel needs to be clean. Otherwise, the dust blocks the sun’s rays, and it loses its performance very quickly. A single month of accumulated dust and it is sometimes a third less yield estimate the researchers of the Massachusetts Institute of Technology (MIT). In general, in the huge solar farms (especially in China, India, the United States) it is therefore pressurized water that is used to clean the photovoltaic panels and it must be imagined that in a desert zone , the water therefore arrives by truck: this cleaning represents 10% of the operating costs of these solar farms. In total, the water used worldwide to rinse solar panels corresponds to the drinking water supply of two million people each year. It gives you an idea of the waste.
You cannot dust the panels without water because it is less effective. And the problem is that using brushes leads to scratches, which also reduce light transmission over time. This is why these MIT researchers are now relying on static electricity to clean the panels, without water.
static electricity
You probably remember that if you rub a plastic ruler over small pieces of paper, these confetti come to stick to the ruler by attraction. Here the principle is the same, but the idea is to charge the dust accumulated on the panel with electricity, this is done using an electrode which passes above the solar panel. Then the researchers apply another electric charge to the solar panel. And all of a sudden, the dust moves, flies away on its own, through an effect of electrostatic repulsion. The technique makes it possible to recover an efficiency of the panels of 95% assure the researchers whose work has been published in the journal Science Advances.
This is a promising discovery because solar energy is expected to reach 10% of global electricity production by 2030. Five times more than today. In France, we are doing less well than Germany, Italy, Spain or Austria, but the production of solar electricity reached a new record last year: + 12% in one year. Solar power today covers 3% of electricity consumption in France, compared to almost 8% for wind power.