NEDO Solar Radiation Database

The Japanese national agency New Energy and Industrial Technology Development Organization (NEDO) in collaboration with the Japan Weather Association have collected data and developed a database on solar radiation.

In particular, the METPV-20 and MONSOLA-20 databases, found as a webapp, are their most recent databases for solar radiation data in Japan. They cover hourly data and monthly data respectively. In addition to these, the Asian area solar radiation database, also found as a webapp, offers access to data for Asia and globally.

NEDO database for Japan

Worldwide NEDO database

Importing METPV-20 hourly data

NEDO hourly data files have a particular format which doesn't allow their direct import in PVsyst. Data are arranged as one day (24 hours) and one variable on each row. This is in contrast with the standard format for PVsyst, which is one time stamp on each row. One therefore needs to convert the data before being able to import it.

The team at ANE hosts a website with a simple guide and conversion script that allows users to transform their hourly files into a format that can be imported in PVsyst via the custom weather data file import. The necessary .MEF file can also be downloaded from the same website.

ANE conversion guide website