1 If the patent application was filed on or after June 8, 1995, the starting patent term is 20 years. 2  This accounts for the vast majority of patents in force today. 3  The 20 year term is calculated based upon the priority filing date, not counting provisional application or the original filing in a foreign country.
The report indicates that the median installed price of PV systems completed in 2012 was $5.30/W for residential and small commercial systems smaller than 10 kilowatts (kW) in size and was $4.60/W for commercial systems of 100 kW or more in size.
In the US, in the south, a 5 kW installed PV system may cost you $20.000, and be large enough to meet all the electricity needs of modest-sized energy-efficient house. But in the north, the same photovoltaic system will provide a lower part of the needs of the same house; and the cost may be different. The solar resource potential counts a lot, and varies significantly by climate. And so does the payback period.