The Japanese government has published official numbers on the installation records for the first three months of the new feed-in tariff system in this PDF-file. Thanks to this tweet by Hiro Matsubara for the link.
These numbers are somewhat difficult to interpret, since there are two sets of them.
One is the number of installations that have been approved by the Ministry of Economy for participation in the system. Many of those have not yet actually started production, and some of them will even not be able to do so in the running budget year (until March of next year).
This number is 1.78 GW for all renewable sources. The government sees this as a good start of the new system (順調な滑り出し）.
Most of that is from solar, with 0.44 GW of residential and 1.04 GW of big scale solar.
Wind contributed 0.29 GW in these three months.
Hydro, biomass, and geothermal are all close to zero.
Clearly, the feed-in tariff system in Japan is strongly dominated by solar power right now. This is good news for bringing costs of solar world wide down even faster. On the other hand, the numbers for biomass and geothermal are clearly inadequate. With the good geothermal resources Japan has, this needs to change.
Update: Lexegese has kindly republished this article.