The number of rooftop photovoltaic permits issued in March by the City and County of Honolulu was down for the 24th month in a row.

In March the city issued 610 photovoltaic permits, down 2 percent from the 622 issued in March 2014, according to data from Marco Mangelsdorf, president of Hilo-based ProVision Solar. The decline was much lower than in February, when the number of permits issued was down 40 percent from February 2014.

Recent actions by the utility give hope that the decline will turn around, Mangelsdorf said.

“In the past three months HECO has sent out around 4,800 pre-approval letters to Net Energy Metering (rooftop solar) applicants on Oahu with 3,000 alone issued last month. That’s likely to bump up PV permit numbers over the following months.”

The solar industry took a hit in 2013 when Hawaiian Electric Co. changed its policy to require solar systems be approved by HECO before installation, citing safety concerns for areas with too much solar connected to the grid.

In January, the utility announced it could double the number of solar systems it can safely connect to the grid.

In March HECO approved 1,987 solar applications that had been waiting for approval since at least October.

The utility promised last year it would clear a backlog of 2,749 rooftop solar approvals pending since at least October, saying most would be approved by April and the rest by the end of 2015. The utility said as of the end of March, it had approved 2,543 of the pending Oahu applications.