Solar permits issued on Oahu declined 16 percent in November to drop the year-to-date total behind the number issued through the same period in 2017.

There were 314 permits issued by the Honolulu Department of Planning and Permitting for solar electrical systems last month compared with 373 in the year-earlier period, according to Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-­based Pro­Vision Solar. Heading into the final month of the year, the 2,597 permits issued were down 2 percent from 2,643 in the year-earlier period. In the past six months, only one month — October — had an increase compared with the same month last year.

“Last December 350 PV permits were issued,” Mangelsdorf said. “Anything less than about 400 PV permits from DPP this month will see the total this year go below last year’s record low since we began crunching the numbers in 2011.”

Mangelsdorf said a record 72 percent of PV permits included energy storage, with LG Chem and Tesla the most popular battery choices.

”Adding storage to existing PV systems has the potential to be a juicy and growing market in light of the reality that the immense majority of the state’s approximately 80,000 rooftop solar electric systems necessarily shut down during a grid outage, with those systems providing no value to the those sweating in the dark,” he said.

At present, Mangelsdorf said the demand for storage retrofit additions is only crawling along with four battery-only permits issued last month and a total of 20 for the year.