Hello Mr.Mermoud, Nedo it's a public db ( http://app7.infoc.nedo.go.jp ) and it provides the same datas of MeteoNorm. I did a comparison and if I didn't do some mistake it's vey similar to MeteoNorm datas (% difference: GHI meteonrm -1% respect GHI nedo datas). If you want to do a deepened comparison it is better to ask an help to a Japanese Pv Syst user because i'mstuding now how to import Nedo db (japanese language is a "little" bit complicated for me and my colleagues. Regards. Fausto