Australia is not the only country enjoying cheaper photovoltaic (PV) solar power systems, with prices falling substantially over the past 12 months throughout the United States.

According to a recent report by the Department of Energy’s Lawrence Berkeley National Laboratory, America’s median household installation price for PV solar systems has dropped by as much as 14 per cent.

The fifth edition of the Tracking the Sun Report, attributes the decreasing costs of solar not only to falling production prices but also in falling costs in labour, marketing and business overheads.

“The drop in non-module costs is especially important as these costs can be easily influenced by local, state and national policies,” said the reports co-author Ryan Wiser.

“Non-module costs represent a sizable portion of PV system installation and the report emphasises the necessity to lower ‘business process’ expenses to help customers.”

The report shows the average installed price of PV systems in 2011 was $6.10 per watt for residential and small commercial systems smaller than 10 kilowatts (kW) in size and was $4.90/W for larger commercial systems of 100 kW or more in size.

Utility-sector PV systems larger than 2,000 kW in size averaged $3.40/W in 2011.

According to report co-author Galen Barbose, the report found that PV installation to new homes was far less than similar systems installed to existing homes.

“The data provide a reliable benchmark for systems installed recently, but prices have continued to decline over time, and PV systems being sold today are being offered at lower prices,” said Barbose.

The market for PV solar has grown rapidly in the US and the report echoes these historical trends, examining over 150,000 homes and businesses across 27 states from 1998 to 2011.

“Our findings are representative of 76 per cent of all grid-connected PV capacity systems in the United States,” said Barbose and Wiser.

Naïm Darghouth, colleague to the authors, says the report is intended to provide policy makers and industry observers with reliable set of standards to help with future trends.

As in Australia, many American State agencies and electricity providers offer rebates to solar customers with the average pre-tax value cash incentives ranging from $0.90/W to $1.20/W for systems installed in 2011, depending on system size.

These incentives have declined significantly over time, falling by roughly 80 percent over the past decade, and by up to 43 per cent from just 2010 to 2011.

The report Tracking the Sun V: An Historical Summary of the Installed Price of Photovoltaics in the United States from 1998 to 2011, by Galen Barbose, Naïm Darghouth, and Ryan Wiser, may be downloaded from: