Installed costs for solar PV have dropped, and economies of
scale improved significantly in 2010, opening the door for much
more cost-competitive distributed solar power. The data comes
from the 4th edition of the excellent report from the Lawrence
Berkeley National Laboratory (NBNL), Tracking the Sun [PDF], and
shows the installed costs for behind-the-meter solar PV projects
in 2010. The following merely copies Figure 11 from that report,
showing the average installed cost of “behind-the-meter” solar
projects in the U.S. in 2010, by project size. This is useful
and shows the significant economies of scale for solar PV in
2010, but the history is important. For context, the following
chart shows the 2010 data along with the 2009 data from LBNL,
with the grey shaded area indicating the cost decreases. The
2010 installed cost data from the California Solar Initiative
(CSI) is also shown in red, helping validate the LBNL data. The
last data point from the CSI is an outlier, likely due to having
too few projects