The number of photovoltaic permits issued in Hawaii County more than doubled in January from the year-­earlier period.

There were 102 solar permits last month compared with 46 in January 2017, according to Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-based ProVision Solar.

“Perhaps the Big Island PV industry will lead the state in turning the corner starting in 2018,” Mangelsdorf said Wednesday. “This kind of news is much needed for an industry that has experienced wild gyrations on the solar coaster.”

Mangelsdorf said one of the largest contributing factors to the increase is the growing adoption of battery storage across Hawaii Electric Light Co.’s service territory on the Big Island.

“While there’s no shortage of bloviating on the mainland about the advent of the age of energy storage, we in Hawaii are actually living and breathing the transition to a 21st-century interdependent and more resilient grid,” he said. “As two new interconnect tariffs, Customer Grid Supply Plus and Smart Export, become available in the weeks to come, those home and business owners who want to go solar electric will have a record number of options from which to choose.”

Under the Customer Grid Supply Plus program, customers can install solar systems that aren’t connected to storage batteries, and receive electrical bill credits for power exported to the utility during the day. However, these customers will have to have advanced equipment that would allow HELCO to reduce what is sent through its grid to prevent any problems with too much energy flowing through the grid.

With Smart Export, customers who install solar systems with batteries have an option to export power during nondaylight hours (4 p.m. to 9 a.m.). Typically, such systems generate power during the day, and this power is largely stored for customer use.