Prime Minister Naoto Kan is considering a plan to require all new buildings in Japan to install solar paneling by 2030. The plan, which would cover all new homes and commercial buildings.

Nuclear power isn't exactly popular right now in Japan, so the government is looking at other sources of power to secure the country's future energy needs. A new initiative called the "Sunrise Plan", which isn't yet in force but should be announced this week at the G8 in France, could help the land of the rising sun turn toward solar energy for more of its electricity.

This could help Japan regain the solar leadership that it lost to Europe some years ago, and it could eventually lead to cheaper solar panels through economies of scale (at first it could drive prices up, but the industry should react by increasing production capacity).
This wouldn't solve Japan's energy problems as long as there isn't a way to efficiently store all that solar power, but it would certainly help increase clean energy production.
And who knows, maybe by 2030 solar panels will be cheap enough $/watt that Japan wont be alone in deploying it on new constructions...