The installed cost of solar power fell to record lows in the first quarter of 2017 because of the continuing decline in photovoltaic (PV) module and inverter prices, higher module efficiency, and lower labor costs, according to an analysis by the US Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL).   While utility-scale solar costs have declined nearly 30%, residential- and commercial-scale solar system prices have lagged behind at 6% and 15% reductions, respectively, a...