There are many studies that confirm this as well. Consequently, periodical cleaning of solar panels is very important in order to produce and deliver the maximum amount of energy to the grid. The effect of dirt and dust on the performance of solar panels depends on various factors and always needs to be estimated or evaluated for individual situations. One can generally assume a reduction of about 10%-20% if solar power plants in Europe or the USA are considered. As soon as the installation is located in dry, dusty regions such as the Gulf region, the effect can be increased and make a difference in power of up to 40%. A 300-megawatt solar plant might spend more than $5 million a year on cleaning and lose at least $3.6 million in energy production lost to dust cover. The costs of installing the system—around $11 million for a facility of that size, a bit more than what he estimates is lost each year with a conventional cleaning set-up—can be recovered within 18 months. Cleaning without water also translates to a savings of 110 million gallons (420 million liters) over 10 years.
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