The polysilicon content in solar cells -- the most energy-intensive component -- has come down to 5 to 6 Watt hour per watt peak , a number that will further decrease to 5 to 5.5 watt hour per wp in 2017.
Ingots: 3 to 4 Watt hour per watt peak
Solar cell: 2 to 3 Watt hour per watt peak
Solar Panel Assembly: 2 to 3 watt hour per watt peak
Testing: 0.5 to 1 Watt hour per watt peak
Total : approx 15 to 18 watt hour per watt peak!
According to the latest life cycle analyses, energy intensity of solar panel including installation is around 25 to 30 Watt hour per watt peak from production to decommissioning.
1Wp Solar Panel generates 1400Watt hours to 1600 Watt Hours per year and 30000 Watt hours over 25 years!
Hence Solar panel’s energy pay back is 1 week & it generates lot more throughout its lifetime!