Honolulu’s roofscape is being repainted in blue-black. From the flattop warehouses of Sand Island to the city’s residential neighborhoods, shiny rectangles spreading across roofing tiles are collecting the tropical sun and powering houses. It would seem like a no-brainer for sunny Hawaii, but it’s just since 2007 that a combination of government and utility incentives and the right economics have ushered in a real solar boom, with capacity roughly doubling each year.
Today, Hawaii leads the nation in rooftop solar per capita: About 10 percent of residential customers, more than 50,000 households, have panels on their roofs, according to the Solar Electric Power Association. That compares with about 0.5 percent nationally.
But in 2013, the boom nearly went bust. Because rooftop solar penetration has moved so rapidly, Hawaii’s utilities are now grappling with both technical and economic challenges that mainland utilities have yet to fully face. How Hawaii surmounts these hurdles could help other utilities sidestep barriers as they ramp up capacity.