My reading was that you lose 2% for the whole life of the panel, until now no one knew why. So, you could do 2% less installation or get 2% more for the investment, if there is a fix for the issue.
You lose 10% of the power output of the solar panel. i.e. solar panels utilize 20% of the solar energy they receive but within hours that drops to 18% for the life of the panel. So yes, it's a 2% absolute drop relative to the solar energy the panel receives, but it's 10% of what the panel was ever able to produce.
Good quality silicon cell pv panels are typically warranted to produce 83% of their original output after 25 years. Degradation is calculated into long term financial figures for really big photovoltaic systems.
You'll see the warranty examples if you look at the PDF datasheets from the top ten manufacturers of 60 and 72 cell panels. Similar for CdTE and other more exotic thin films.
yes, however, ROI is more greatly affected by lowering the total bill of materials cost for a large PV install, and in particular the $ per W cost (at STC, standard test conditions) rating for each panel. Going from $0.72/watt to $0.46/watt in single pallet quantities of 20 panels was a huge difference.
