The number of solar permits issued on Oahu rose in February for the second straight month after declining for two years in a row.

There were 194 permits issued by the Honolulu Department of Planning and Permitting for solar electric systems last month, up 26 percent from 154 in the year-earlier period. Of the most recent total, 60 percent, or 116, included battery storage. In January, Oahu solar permits issued rose 18 percent to 229 from 194. Of those 229 permits, 53 percent, or 122, included energy storage.

“While not quite yet a definitive trend, I would very much like to believe that the Hawaii ‘solar coaster’ bottomed out last year and is now building some upward momentum after years of slowdown,” said Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-­based ProVision Solar.

Oahu, the largest solar electric market in the state, had been shrinking with just 2,993 solar permits last year compared with 4,591 in 2016 and 7,493 in 2015. The peak for photovoltaic permits issued on Oahu occurred in 2012 with 16,715, leaving last year’s number down 82 percent from the all-time high.

“Nowhere else in the country is residential energy storage (battery systems) being deployed as part of new PV system installations as vigorously as we’re seeing here,” Mangelsdorf said. “On the macro level, the storage arena has become one of the hottest energy playing fields in the world.”

Mangelsdorf noted that the Tesla Gigafactory outside of Reno, Nev., will soon have competition from a growing number of battery megafactories either under construction or on the drawing board in China and South Korea.

“(That) means that the volume of energy storage hitting the global market is going up exponentially, accompanied, we expect, by declining prices,” he said. “Solar PV used to be the hot, new energy frontier. Now it’s battery storage, and it couldn’t come at a more opportune time.”