Tokyo Electric Power Co. cut power in the greater Tokyo area on Wednesday morning in an effort to conserve electricity and avoid a nationwide power outage.

The third day of blackouts affected 530,000 households in parts of Saitama and Yamanashi prefectures from 6:40 a.m. for around three hours, with the four other groups comprising Tokyo Electric' s service area on standby for power outages during the day.

The subsequent outages will be dependent on supply and demand, but TEPCO has said that two rounds of cutoffs are possible for two of the groups if power supply shortages become a factor as the temperature drops later in the day.

Peak demand is between 6 p.m. and 7 p.m., during which time the company said demand will outstrip supply.

TEPCO's daily capacity is 33 million kilowatts of power and demand is expected to top 38 million kilowatts during the peak times.

A total of 2.39 million household will be affected by the blackouts, according to TEPCO.

Rain on Wednesday morning provided some relief for the utility' s hydrogen power plants, enhancing supply, and due to this power supply in all areas on Wednesday morning was provided as usual.

Tohoku Electric has begun its own power rationing rotation in the north of Japan, although those areas worse affected by Friday's quake and tsunami are exempt from the planned outages, the company said.

Tohoku Electric opted not to enforce blackouts on Wednesday morning as supply was ample and will consider outages in the afternoon on a needs must basis.