A solar power array needs one very large, very obvious thing to operate: the sun. Since they cloak the rays of the sun, clouds are the enemies of of large scale solar systems, thieving efficiency, and causing surges, fluctuations, and headaches for both the power grid and the utility operator.

Now those pesky clouds may have met their match due to a recent study conducted by the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL). The (NREL) has produced a massive data set showing what happens, second-by-second, when clouds pass over a solar power installation.

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The study utilized 17 measurement stations near Hawaii’s Honolulu International Airport on the island of Oahu and collected data at one-second intervals over the course of an entire year. The collected data “allows us to set up a solar-monitoring network that simulates exactly how clouds would impact a large photovoltaic (PV) system,” said NREL Senior Scientist David Renne. “The time-synch data are unique. All 17 stations make a one-second measurement at exactly the same time. This allows the array to “see” clouds moving through and simulates how a PV system might behave.”

By understanding the characteristics of cloud shadows that pass across a large PV system, utility officials can devise strategies to better manage those fluctuations so the grid isn’t adversely impacted. The data set is of great interest to utilities, developers of large-scale  PV systems, forecasters, system operators, laboratories and universities.