Environmental Leader

The cost to install solar has dropped 30 percent over the past 10 years, according to the Department of Energy’s Lawrence Berkeley National Lab.

Most significantly, the cost of PV modules dropped from 2007 to 2008 after three years of remaining relatively flat, according to a new report from the lab, “Tracking the Sun II: The Installed Cost of Photovoltaics in the U.S. from 1998 – 2008.”

By contrast, cost reductions from 1998 through 2007 came through declines in labor costs, overhead, inverters and others aspects of the systems, reports Energy Efficiency & Technology.

The study, which looked at more than 52,000 grid-connected systems installed from 1998 to 2008, found that average installed costs fell from $10.80 per watt in 1998 to $7.50 per watt in 2008.

Large commercial systems of 500-750 kilowatts now cost an average of only $6.50 per watt, according to the report, compared to $9.20 a watt for smaller systems of less than 2 kilowatts, the kind found on many homes.