Zheng Long is feeling a little relieved with the current weather in Shanghai.

So far, summer has been unusually cool.

But Zheng knows conditions can change abruptly. Shanghai weather at this time of the year is characterized by long heat spells broken only by short bursts of torrential rain.

This is also the season that is known to put a heavy strain on power supplies in the city of 15 million, and many residents are turning their home and workplace air conditioners on at full blast.

But this year, Zheng, the city's energy tsar, is preparing to battle the expected energy crunch with strong action.

Shanghai has worked out a three-tier mechanism to ensure sound power supplies even at peak demand, said Zheng, director of the electric division under the Shanghai Economic Commission, the administrative institution in charge of power.

The most important thing, according to Zheng, is for Shanghai to take all possible measures to ensure that Shanghai's power-generating facilities are put into full swing in the peak months of July and August.

Existing power generation capacity in Shanghai reaches 11.40 million kilowatts this year. But a huge gap still exists between supply and demand. Last year, the actual power usage at peak time was some 16.7 million kilowatts.

Shanghai, viewed as one of the most vibrant powerhouses in the Chinese economy, is also the country's most energy-thirsty region. And the situation became more serious when neighbouring regions in Jiangsu and Zhejiang provinces began to face the same dilemma and could not have extra power to share with Shanghai a few years ago.

However, Zheng feels he is pretty confident that he will not face as many complaints as those last year because the State Grid this year will lend a helping hand to the East China Grid in providing power to the city.

Enterprises will not face the dilemma of being forced to suddenly turn off their power since an early warning system has been established to notify enterprises beforehand when they are scheduled to shut down their power systems.

Enterprises, especially high-energy consuming and polluting ones, will still have power cuts in peak seasons, said Yu Qinde, a senior official with the Shanghai Electric Power Company, a major electricity supplier and distributor in Shanghai.

Peak power demands this year are expected to reach 19 million kilowats this year, up 12.4 per cent year-on-year, Zheng and his colleagues predicted.

"But that is just our forecast for maximum demands in extreme cases, and it will not become an everyday occurrence."

The solution will rely on two channels, Zheng said, referring to the early completion of several newly built power plants in Shanghai and the practice of receiving additional power from other regions.

Preparations began in 2003 for a possible power shortage, when the local economy became overheated, driven by robust exports and imports and growth of the high-tech sector.

Development of new plants in suburban Fengxian and Caojing area could add some 0.6 million kilowatts in supply capacity this summer, according to Zheng, adding that the plants should be completed by next year.

The city is to build up power bases in five suburban areas of Waigaoqiao, Caojing, Shidongkou, Minhang and Lingang, with a combined capacity of 27.70 million kilowatts by 2008.

At the same time, Zheng said Shanghai is to receive a total of 5 million kilowatts in power supplies from other regions through the East China Grid and State Grid.

"At the moment, we have a promise of some 4 million kilowatts, thanks to the support from other regions," said Zheng.

He said that, among those promised, a large number are a contracted quota signed months and even years ago with power suppliers from other regions.

"We are going to get more contracted power supplies through other market-oriented methods," said Zheng, adding that a third of power supplied from the Three Gorges to the East China market will go to Shanghai in coming decades.

This is going to be Shanghai's major method to get additional power supplier from outside the city when self-capacity is not enough, according to Zheng.

China added 50 million kilowatts to new power capacity last year, and this year, newly developed power capacity could reach 68 million kilowatts.

But the Qinshan Nuclear Power Plant in neighbouring Zhejiang Province and the giant Three Gorges Power Plant will not play a leading role in powering Shanghai this year.

"Some of the generators in the Qinshan plant are undergoing maintenance at this time," said Zheng, adding that the original plan for transferring power from Three Gorges plant has also been delayed.

"At a normal time, Shanghai's power supply is enough to meet the increasing demand," said Zheng.

Combining both industrial and residential demand, Shanghai's general power consumption stood at 10.5 million kilowatts, but the peak load could hit 18.50 million kilowatts in the summer, mainly due to the use of air conditioning.

"The local government needs to draw up more economic-driven policies to adjust manufacturing and the use of air conditioning facilities in Shanghai," said Long Weiding, secretary-general of the Shanghai Institute of Refrigeration and Cryogenics Engineering.

He estimated that a lift of the energy efficiency ratio of chillers to a higher level could help the city depress electricity peak-loads by 60-80 million watts, or save 28-36 million yuan (US$3.38-4.34 million) a year.

One of the constraints, or risks, for Shanghai's power capacity will be coal supplies from North China. Repeated coal mine accidents result in unstable supplies and rising coal prices.

(China Daily June 29, 2005)