Sunpower, an American company, sells the solar module with the highest efficiency of 19.6%. Number three Sanyo HIT technology combines a crystalline silicon cell with an additional amorphous silicon layer. The difference between the leader and the number 10 is 3.4%; Although a small difference, it could be relatively significant. The difference could mean you will use less space on your roof to achieve the same system power or energy yield. It also means you need less Balance Of System components such as mounting hardware. Does it pay to use the higher efficient modules?
This ranking does not say anything about the module cost per Watt, nor about the most important concern, the cost per produced solar kWh. It could mean that a module of lower efficiency is so much cheaper that the extra cost for other system components (more frame, cables, installation work) can easily be covered by the money saved on the modules. Also, some modules perform better in real life conditions rather than in the standard test condition as mentioned on the their certified datasheet.
All but one of the the top 10 modules are manufactured in Asia. The number one, Sunpower, is from the US, but their cells and modules are manufactured in the Philipines. Several well known brands did not make it into the Top-10 as most are young and unknown brands.It will be interesting to see what market position these young companies obtain. The future will tell as the top 10 listings will continue to change.