SHANGHAI: The Yangtze River Delta has turned to wind power in its quest for cleaner energy, with Shanghai spearheading the drive.

Last month, the eastern metropolis opened China's first wind- power science museum next to a cluster of huge three-blade wind turbines installed last year in the south of the city.

The two-storey museum, which shows how wind has been used over the centuries to generate power, attracts an average of 100 visitors per day, mostly students and tourists, according to employee Yan Meihong.

From the second floor, visitors can see eight of the 11 giant white wind turbines, each with a capacity of 1.5 megawatts (MW) and 65 metres tall, in nearby Forest Park.

The turbines, along with three in Chongming District, can meet the electricity needs of 20,000 people.

Shanghai, one-third of whose power is imported, aims to promote this clean energy even more, partly encouraged by the country's new Renewable Energy Law.

The law requires major power companies to ensure that at least 5 per cent of their generators are fuelled by renewable sources by 2010.

According to the National Development and Reform Commission, the country's top economic planner, wind power facilities with a total capacity of 30,000 MW will be built by 2020.

Most industry experts, however, believe the potential is much higher.

"We want to add 10 similar turbines in Nanhui District, and some bigger ones in Chongming District as well," said Hu Chuanyu, a senior engineer of Shanghai Wind Power Co.

"But the global wind power market is so hot that we are worried about where to find turbines."

Having worked in the wind power sector for 10 years, Hu estimates that Shanghai alone has a potential onshore wind power capacity of at least 3,000 MW.

That amount would meet the daily energy needs of about 1.2 billion average Chinese homes.

Although that is only about 10 per cent of the city's total demand, it is still significant for the city of Shanghai, which has a population of more than 10 million and a power shortage of 10 million kilowatts. The shortage equates to the power supplies of 2.5 million ordinary households.

At the estuary of the Yangtze River, Shanghai benefits from both ocean salt and silt carried by it, creating large patches of tidal land that are extending 100 metres a year on average.

"That makes it an ideal wind farm location, as tidal land is accommodating enough to hold big windmills," said Hu.

A spacious flat place is also important for ensuring steady wind speed, which is crucial for later power networking and facility maintenance.

The coastal city also has a large untapped sea area that is suitable for offshore wind turbine construction, a likely future trend for wind farms as they take up no valuable land resources.

"Shanghai is planning a large offshore wind farm in the East China Sea, which could be the first one in the country," said Hu.

The proposed wind farm may even be located by the East China Sea Bridge to fuel a new residential area to be constructed nearby.

But it is not an easy task to erect turbines at sea in terms of cost, construction and technology.

"A single blade for a turbine can be as high as a 10-storey building. So imagine how much effort will be needed to erect scores of turbines on the water," Hu said.

It would make the cost far higher than building turbines on land, which already requires funding of about 20 per cent more than that of a thermal power station.

And for a country such as China, which relies heavily on imported turbines, it also means more sophisticated technology.

China began to follow the rest of the world in manufacturing turbines in the 1970s, but still lags far behind, said Yuan Guoqing, associate professor of Shanghai-based Tongji University's School of Aerospace Engineering and Applied Mechanics.

The difficulty, he said, lies in the design of turbine blades the most vital part of a turbine.

"They look simple, but involve multi-disciplines including aerodynamics, materials and automation. Their costs account for approximately one-third of the total of a turbine," Yuan said.

The most high-tech windmills, each with installed capacities of more than 1.5 MW, are all equipped with variable speed turbines, where blades can change angles and running speed against different winds to produce more stable electric currents.

But China is still behind many other countries in the technology, according to Yuan. He added that some domestic universities were planning to set up wind power majors to train future turbine designers.

"We at Tongji University are also considering establishing a wind power research centre someday," he said.

One inspiring development, however, is that an energy research institute in Guangzhou is experimenting with a new turbine that adopts maglev (magnetic levitation) technology, according to Hu.

It is said to be able to utilize winds at speeds of just 2.5 metres per second, in comparison with the driving wind speed of more than 3.5 metres per second needed for existing turbines.

China started wind farm construction in 1986, with the first site in full operation in Rongcheng, a county in East China's Shandong Province.

The Yangtze Delta, which boasts a long coastal line with the potential to greatly benefit from wind power, trails somewhat behind other areas, but has good future prospects.

Besides Shanghai, Jiangsu and Zhejiang provinces have also drawn up plans to develop the green energy.

In Dongtai, Jiangsu Province, a wind farm with a total installed capacity of 200 MW is under construction. It is expected to be completed in 2008, generating annual electricity of 400 million kilowatt hours.

Also in the province, the largest wind farm in Asia is being built in Rudong, a city with an average onshore wind speed of 7 metres per second.

With a planned installed capacity of 850 MW, the wind farm will accommodate about 430 turbines, each with a capacity of 2 MW, according to Zhao Shengxiao, an engineer with the Central China Investigation and Design Institute, which carried out surveys in the area ahead of construction.

The province hopes to possess one-fifth of the total installed capacity of wind power in the country by 2010 by erecting more turbines.

Hu said: "Jiangsu has geographical advantages, with large plains, for instance. Its potential capacity of wind power along the coast could be as much as 100 million kilowatts."

Zhejiang, although hindered by its mountainous and compact geography, is also planning to make the most of its wind resources. One of its island cities, Zhoushan, has proposed an offshore wind farm with an installed capacity of 200 MW.

Statistics have shown that China has a total potential wind power capacity of 1 billion kilowatts, with about 70 per cent along the coast.