Solar permits issued on Oahu rose 42 percent in May to mark the fifth straight month of increases.

There were 297 permits issued by the Honolulu Department of Planning and Permitting for solar electric systems last month, up from the 209 in May 2017, according to Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-­based ProVision Solar.

Through the first five months of this year, DPP issued 1,131 photovoltaic permits, up 21 percent from 937 in the first five months of 2017.

The top contractors ranked by permits pulled on Oahu were Sunrun, RevoluSun and Hawaii Energy Connection.

“The permitting of systems deploying energy storage remains strong with 60 percent of May PV permits including batteries,” Mangelsdorf said. “There are concerns, however, that the tight supply of the most popular batteries will act as a constraint over the balance of the year to getting these permitted systems up and running in a timely fashion.

“While the macro trend for energy storage production indicates a much larger volume of supply in the years to come, the challenging on-the-ground reality is one of relative product scarcity and higher pricing.”

Oahu, the largest solar electric market in the state, had been declining 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.