Thanks to power shortages, Shanghai factories have been told to work only at night and tourist areas will be unlit As temperatures soar this summer, the mainland's richest areas are feeling the heat. Shanghai and Guangdong report worsening power shortages as electricity-draining air conditioners are cranked up. Some power producers worry that the problem could continue even past the summer, state media said yesterday. Due to high temperatures and rapid economic development, Guangdong would face its biggest power shortfall from July to September, though the gap was expected to persist until the end of the year, the Southern Metropolis News said. The Guangdong Power Group predicts power consumption in the province will rise 14.5 per cent this year to about 233 billion kWh, forcing the government to adopt energy-saving policies and spend 19 billion yuan to improve the grid. Shanghai, meanwhile, has taken conservation steps, including turning off the lights of the historic Bund district, after temperatures hit a high of 37 degrees Celsius at the weekend. The city turns off all scenic lighting after the temperature hits 35 degrees. Shanghai's power use hit a record peak of 14 million kW yesterday. Office buildings near the popular Xintiandi entertainment district reported brief power outages. A local newspaper reported that the city was preparing to seed the clouds to induce rain and bring down temperatures, but officials could not immediately confirm whether a rainstorm last night was man-made. The mainland's commercial capital has just ordered a further 700 companies to halt production during the day and work at night, bringing the total to 1,200. Between 2,000 and 3,000 companies will offer workers this week off to conserve power, local media has said. 'The impact has been enormous. There are some orders we haven't been able to fill,' said an official of a Taiwanese insulation company, which has been ordered to shorten its work week to five days from seven. Another company forced to move shifts to weekends and nights complained that efficiency had dropped because of exhausted workers. 'The workers are coming to work tired,' said the general manager of a US-owned manufacturing plant. Under measures previously announced by Shanghai, entertainment venues can only turn on central air conditioning after 4pm. Government offices, hotels and commercial buildings must keep their thermostats above 26 degrees. An executive at a luxury Shanghai hotel said the rules were difficult to enforce, since guests could set the thermostats in their rooms and the kitchen needed to keep temperatures low for food hygiene. 'For the hotel side, it is quite difficult. This is a regulation, but in some specific cases we can't control the temperature,' the executive said. Nearly two-thirds of the mainland is suffering from some form of power shortages, state media has reported. Record high temperatures last year caused a power shortfall in Shanghai, causing blackouts in some districts.