As a result of the Fukushima nuclear power plants shutting down after the quake, there is insufficient electricity generated for the Kanto area. For this reason, there will be rolling blackouts starting on 14 March, which will continue for weeks. This measure will last until the power plants start to work again, or the company finds the necessary extra capacity to generate power to meed the demands.
Even though the power plants are in Fukushima in northern Japan, they are operated by Tokyo Electric Power Company (TEPCO) which supplies electricity to the following prefectures: Ibaraki, Tochigi, Gunma, Chiba, Saitama, Tokyo, Kanagawa, Yamanashi, and parts of Shizuoka. This area will be divided into 5 groups, and each group will have a blackout of 3 hours or so. All but the central parts of Tokyo will be affected. Information regarding blackouts should be available at the TEPCO website: http://www.tepco.co.jp/en/index-e.html (English version)
The company has drawn a lot of criticisms – rightly – for their failures in managing the nuclear power plants and in its handling of information. It has been very bad at releasing information as to which localities are in which group, and when the blackout for each area will start.
For those who require a constant supply for electricity, such as for medical reasons, the company will try to provide them with mobile or small generators. However, the number of generators is limited, and there may be logistical problems to have such generators delivered and installed in time for the first blackout.
Everyday life is going to affected. There will be fewer trains on the move, and traffic lights will cease to work during the blackout, so transport will be a problem. Water supply may be disrupted, as well as telephone and access to the internet. Those living in high-rising apartment blocks or working in offices ought to be very careful about the time the blackout starts, else they may end up being stuck in lifts / elevators. There are other problems, such as leaving the iron switched on when the blackout starts: it may go cold, but will be hot again as soon as the blackout is over. The same could be said for things like hair dryer.
(Note) There are two nuclear power plants in Fukushima: No 1 plant has 6 reactors, of which numbers 1, 2 and 3 were in operation when the earthquake struck; No 2 plant has 4 reactors.