By last year only 5 of Japan’s 42 nuclear reactors had come online, providing less than 3% of Japan’s electricity. The increase in Japan’s emissions from the power sector after Fukushima was the carbon equivalent of adding nearly 18 million cars to the road.
On September 14th Japan's Atomic Energy Commission announcedthat Japan should try to get at least 20% of its energy from Nuclear by 2030. To meet the 20% by 2030 goals more than half of Japan’s existing reactors would need to be reopened.
Japan is in a pretty unique situation when it comes to energy; it’s a densely populated island nation and has very little in terms of fossil fuel reserves. After the nuclear shutdown, Japan had to import around 84% of their energy requirements (all fossil fuels), throwing a wrench in their attempt to cut emissions. Since Fukushima Japan has managed to emit record amounts of CO2 despite cutting demand by nearly 15%. This helps to show that cutting demand isn’t enough if you aren’t working diligently to decarbonize your energy production; you may fail to reduce emissions or even raise them. This is why the JAEC wants more nuclear energy, because it will help to decarbonize Japan while they phase out fossil fuel generation.