Severe power shortages in northern Vietnam are beginning to ease, allowing manufacturers to extend operating hours after blackouts curtailed production.

Thousands of factories in the region, which house plants owned by Samsung Electronics Co. and suppliers to iPhone maker Apple Inc., have gone without sufficient power since nationwide outages began May 2023. Northern provinces, including Bac Giang, have been worst hit by the crisis after searing heat cut the supply of hydropower at a time of low coal supplies and failures at outdated power plants.

Manufacturers in Bac Giang can now operate from midnight until 5 p.m. daily, said Dao Xuan Cuong, chairman of the management board of the province’s industrial zones. During the week of June 5, factories were told to curtail production between 5 p.m. and 7:45 a.m.

Bac Giang is giving industrial parks priority access to power during the day while saving electricity for citizens at night, Cuong said. Plants should be able to run production lines normally in a couple of weeks, he said.

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The measures will apply country-wide, he said. “However, each province may have a slightly different solution depending on its priorities.”

Power supplies in the north improved during the weekend of June 11 after several malfunctioning coal-fired generators were repaired, and some reservoirs saw water levels rise after light rain.

More rains are forecast, according to the national weather agency, which will ease the strain on hydropower supplies. Starting June 13, the agency also expects a gradual easing of the heat wave that has gripped the north since the beginning of June 2023, although high temperatures in central Vietnam are expected to persist for several more days.

Extreme heat increases the demands on the electricity grid from fans and air-conditioners, as well as sapping the water levels on which hydropower relies.