Power-starved North Korea has been urging its citizens to conserve electricity as winter sets in, and after its key benefactor China at one point cut oil flows this year.
North Korea, with a population of about 22 million, produces a little more than 2,000 megawatts of electricity and has trouble keeping the lights on at night across the impoverished country. Across the border, South Korea, with a population of about 48 million, has power capacity of some 60,000 megawatts.
In official media reports late on Friday, North Korea said it wants households and factories to cut down on their electricity use while also saying it started construction of a hydroelectric plant to help meet the country's energy needs.
"A campaign for economising and making an effective use of electricity is being vigorously launched in the DPRK (North Korea) as winter comes round," its KCNA news agency said.
Electricity demand is high in winter in North Korea when shorter days and frigid cold grips the country. Energy shortages have been exacerbated this year by Beijing's decision to stem the flow of oil to the North.
Chinese data shows that Beijing sent no crude to its neighbour in September - before Pyongyang's October 9 nuclear test but two months after the North strained ties with Beijing by test-firing missiles despite calls from China for restraint.
"After the missile launchings, China punished North Korea for hurting China's fundamental interests," Xia Liping, a regional security expert at the Shanghai Institute for International Studies, a government thinktank, told Reuters.
Chinese crude oil exports to North Korea resumed in October, data shows.
South Korea has offered to supply North Korea with 2,000 megawatts of power if Pyongyang agrees to abandon its nuclear weapons programme.
North Korea has boycotted six-country nuclear talks for over a year but said after the nuclear test in October it would return to the discussions. Envoys from the six-parties met last month in Beijing but failed to secure a date for Pyongyang's return.
North Korea, which says self-reliance is a top policy priority, has relied heavily on hydroelectric power. Pyongyang has said it built 6,500 power plants, mostly hydro power plants, between 1998 and 2002, according to Kim Kyung-sool, an economist specialised in North Korean energy policies at the South's Korea Energy Economics Institute. But their capacity has been small, hardly makes a dent in the country's energy shortage, he said.
"North Korea has been trying to build small- and medium- sized power plants, but they are mostly for power supply to small villages and not linked to a national grid," he said.