Feed-in tariff (FIT) in Japan started in 2009. For solar panels set at home, power companies shall buy the electricity for 10 years. This means that power companies would not buy electricity after 10 years (or buy electricity with zero yen).
Apparently, there will be higher demands for home batteries to store electricity generated by solar panels, after 2019 in Japan.
Tesla PowerWall costs reasonably but other companies’ products (including Panasonic ones) are quire expensive.
Wish early release of PowerWall in Japan.