A study by the Department of Energy's Lawrence Berkeley Labs reports that the installed cost of solar photovoltaic systems continues to fall rapidly. The biggest reason is that the PV modules have become much less expensive. But other costs, including installation, are also falling. In 2011, the average cost was $4.90 for larger commercial systems of 100 kW or more in size, but prices have continued to fall since then and systems today are being sold for less. Click here for more information about the falling costs for installing solar photovoltaic systems.