The summer power-saving campaign sparked by the Fukushima nuclear disaster kicked off Monday across Japan, but without the government's usual numerical targets.

The three-month campaign is the fifth of its kind since the March 2011 earthquake and tsunami triggered the nuclear crisis that shut down all of the nation's reactors. Only two are back online.

The campaign applies from 9 a.m. to 8 p.m. on weekdays and excludes the Bon holidays from Aug. 13 to 15.

Amid the nationwide debate on phasing out nuclear power, companies and households have gotten used to saving electricity during the hottest and coldest parts of the year so utilities can deal with demand contingencies as they return to thermal power generation.

The government campaign, which runs through the end of September, is based on the usual surge in summer air conditioning use. The request applies to all areas served by the nine utilities with reactors, thereby excluding Okinawa Electric Power Co., which doesn't have a nuclear plant.

"We would like to ask citizens and industries to voluntarily cooperate in saving electricity," industry minister Toshimitsu Motegi said Friday.

According to the Meteorological Agency, temperatures are expected to be higher than usual in July and August and remain high into September for eastern Japan.