The article doesn't question Hawaiian Electric Co.'s argument that power fluctuations due to clouds over rooftop solar systems are threatening the grid.
Even on small islands like Oahu and Maui, the rooftops generating power are distributed geographically over a much wider area than individual clouds are. The resulting electricity fluctuations are partially averaged out and aren't unlike fluctuations resulting from air conditioners turning on and off.
Did it occur to The Times that the Hawaiian power company is facing a no-growth market and therefore has a strong incentive to discourage rooftop solar? This is similar to California, where big solar installations are encouraged (threatening our deserts and endangered species) while rooftop solar is less so.