A new study on the installed costs of solar photovoltaic (PV) power systems in the U.S. shows that the average cost of these systems declined significantly from 1998 to 2007, but remained relatively flat during the last two years of this period. Researchers at the Department of Energy's Lawrence Berkeley National Laboratory said the overall decline in the installed cost of solar PV systems is mostly the result of decreases in non-module costs, such as the cost of labor, marketing, overhead, inverters and balance of systems.

"Solar will be big when it is cheap. This report demonstrates that local market development plays a key role in bringing solar costs down." -- Adam Browning, Executive Director, Vote Solar