Analyzing some 820,000 individual photovoltaic (PV) systems—around 85 percent of the cumulative total U.S. installations through 2015—the researchers behind the study documented a median price decline of US$0.20 per installed DC watt for residential systems, a 5 percent dip, and a decline US$0.30/W for both small and large nonresidential systems, a 7 to 9 percent reduction.
The declines continued a six-year trend of price declines in installed solar—but the dynamics driving the declines seem to be shifting, at least in the U.S. In the years through 2012, annual price declines stemmed largely from falling prices in PV modules themselves. But since then, module prices have largely been flat. Instead, the recent LBNL study ties much of the year-to-year price decline for 2015 to decreases in “soft” costs such as marketing, system design, and installation labor, as well as to lower costs for some non-module equipment such as racks and inverters.