CCRA

Easily justified if you need both backup and to sell to grid. Typical configuration is that you have say 90% of panels selling power to grid, and 10% of panels for backup purposes. With this you don't need to keep panels offline for use in backup, so have 100% to sell power to the grid. When power is down you also have 100% of panels charging batteries. In my case (though different country, and your mileage may vary depending on # of panels) using the 10% backup panels for sales to grid reduces the payback from 6 years to 4 years (even with extra cost). The question is, do they have a 50Hz model?