Maui County was hit hard by the slowdown in solar permits last year.

The number of permits issued plunged 59 percent to 676 from 1,657 in 2016, according to data compiled by Marco Mangelsdorf, who tracks rooftop solar permits and is president of Hilo-based ProVision Solar. The 2017 total was off a more dramatic 80 percent from 2015.

“These kinds of numbers put even the most gifted solar spinmeisters in a hard place,” Mangelsdorf said Monday. “On the near horizon is the announcement of the decision by the Trump White House on the depth and breadth of the imposition of tariffs and quotas on the importation of foreign-manufactured PV modules into the U.S.”

Mangelsdorf said it remains to be seen how much the tariffs and quotas will hurt the local solar industry and to what extent have local photovoltaic companies stocked up on inventory in an attempt to at least delay the pain of having to pay more for solar modules this year.

“Also looming large is the timeline of when new interconnect options will actually be available from the Hawaiian Electric Companies,” Mangelsdorf said. “There are a number of challenging issues when it comes to the stipulated controllability of new rooftop solar systems going in under one or more of these new programs, and there are concerns among the parties as to how reliable wireless communications can be established and what constitutes an acceptable telemetry interface. The PUC (Public Utilities Commission) has its work cut out for it.”