The solar industry continues to dim as the number of solar energy system permits issued on Oahu in January was cut in half from the same period last year.

In January the City and County of Honolulu issued 194 photovoltaic permits, according to data compiled by Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-­based ProVision Solar. This was a 52 percent decline from the 407 solar permits issued in January 2016.

The number of issued permits has been dropping since the state ended a popular solar energy incentive program called net energy metering (NEM) in 2015. NEM participants are credited the full retail rate for the excess energy their solar system sends into the grid.

The only program still available for Hawaii residents who want to add rooftop solar and stay connected to the electric grid is self-supply. The program restricts solar owners from sending excess energy into the grid but allows customers to draw power from it when needed. Most systems need batteries to meet self-supply requirements.

“We’re all waiting for that desperately needed dramatic uptick in the adoption of customer self-supply systems,” Mangelsdorf said, “and hoping that it comes before it’s too late.”

A snag in selling a solar system under the new program is the cost of the battery. A Tesla Powerwall 2 is priced at $5,500, and the installation and supporting hardware cost $1,500.

A handful of bills have been introduced this legislative session to add an incentive to the industry.

Two measures that propose a tax credit for energy storage systems — Senate Bill 365 and Senate Bill 361 — are scheduled to be heard this session.

Lawmakers from the Senate and House of Representatives also have introduced House Bill 1593 and Senate Bill 660, which require the Hawaii Green Infrastructure Authority, the agency assigned to run a $150 million loan program, to use the funds to offer rebates to customers who buy batteries.

Hawaii lawmakers created the loan program in 2013 to make rooftop solar systems more affordable.

The Green Energy Market Securitization program, or GEMS, raised roughly $150 million through a bond sale and was to have lent that money by the end of November. To date it has lent roughly 2 percent of the funds, while $33 million in interest on the bonds is being repaid by Hawaii ratepayers via a $1.50 “Green Infrastructure Fee” on every monthly electrical bill.

“We need something,” said Colin Yost, principal at Honolulu-based RevoluSun. “If we wanted to actually kick-start the program and make it more obviously accessible to a larger market, then having a rebate like the one proposed in the Senate bill and the House bill would be enormously helpful. ”

Yost said the wait to get permits from the city for the batteries and the availability of battery products have contributed to the slowed popularity of solar under the self-supply program.

“It’s been slow going establishing an expedited permitting process for battery installations,” he said. “We continue to work closely with the City and County of Honolulu to speed things up, but we’re not there yet.”