Japan's government began imposing energy restrictions on companies, shopping malls and other major electricity users on Friday to cope with power shortages following the country's nuclear crisis.

Big factories, office buildings, universities and department stores in the Tokyo area must use 15 percent less electricity than a year ago. Electricity is in short supply due to the loss of the Fukushima Dai-ichi nuclear power plant, which was crippled by a massive March 11 earthquake and tsunami.

The restriction is in effect from 9 a.m. to 8 p.m. on weekdays from July 1 to Sept. 22, and violators face fines of up to 1 million yen ($12,400). The limit does not apply to households, but the government has urged them to conserve energy.

"We ask their cooperation so that we can all overcome the energy crunch," trade ministry official Satoshi Koyanagi said. The government has already implemented energy-saving measures such as disabling extra elevators and turning off lights.

TEPCO expects to supply 53.8 million kilowatts for Tokyo and its vicinity in July, short of an estimated demand of 60 million kilowatts.

To cope with the shortages, Sony Corp. said it would turn off air conditioning at its Tokyo headquarters after 6 p.m. It also brought forward the start of the business day by one hour to 8:30 a.m., spokesman Atsuo Omagari said.

The Tokyo Stock Exchange said it has turned off its electronic price ticker, and will not receive visitors until the end of September.

"We are turning off all lights and air conditioning in the visitors' areas. This is to save electricity," said Yukari Hozumi, a stock exchange spokeswoman.

Major department store Mitsukoshi said it has turned off unnecessary lights and disabled some elevators and escalators.

East Japan Railway has been operating fewer train services from noon to 3 p.m. in the Tokyo area since June 24.

The government also has launched a campaign urging office workers to shed their suits and ties for lighter clothes such as polo shirts to endure the country's summer heat.