Powering on

Accompanied by the furious rumble of machinery, the Yuhuan power station on the coast of East China's Zhejiang Province is humming with activity.

Operated by China Huaneng Group, the nation's largest power producer, Yuhuan's third 1,000-megawatts ultra-supercritical unit has been put into commercial operation since a week ago.

The facility, which will have four 1,000-megawatt ultra-supercritical units when complete, is the first and largest power plant in China, as well as the country's first to use ultra-supercritical technology.

It sets a new milestone in construction of more efficient and cleaner coal-fired plants through the use ultra-supercritical generating units, which utilize one of the most advanced thermal power technologies in the world today.

According to the London-based World Coal Institute, power plants that use ultra-supercritical generating units enable efficiencies up to 50 percent and along with a significant reduction in carbon dioxide emissions. The energy efficiency of conventional power plants currently in use in China is 30 percent to 40 percent.

"The total budget of this plant is 9.6 billion yuan, higher than the cost of conventional power plants," says Li Jianming, general manager of Yuhuan facility. "But the value is huge. It adopts high efficiency dust removal and desulphurization devices for environmentally friendly operation that meet the national energy saving and emission reduction policies, with an overall efficiency of 45 percent.

"The first two 1,000-megawatt units went into commercial operation at the end of last year. The third was finished on November 11 and the next one is under construction. When it is ready for operation in 2008, 22 billion kilowatt-hours of electricity will be generated annually," he adds.

"About 10 such power plants are now being built by Chinese power generating companies and international manufacturers, three of which have been put into commercial operation," says Shen Qi, deputy general manager of Yuhuan power plant. "There are more ultra-supercritical units coming in the near future. Our equipment supplier said they have received orders for about 30 such units since our first trials."

"It will be a trend that ultra-supercritical technology will become more popular in China's thermal power plants because of their higher energy efficiency and their lower emission of pollutants," says Zhou Xi'an, director of the Office of National Energy Leading Group.

According to statistics from Huaneng, after half a year of operation, its ultra-supercritical units consumed 283.2 grams of coal to produce one kilowatt-hour of electricity, while medium- and small-sized generators need 380 to 500 grams.

China's power equipment manufacturers are now able to make the ultra-supercritical units. Shanghai Electric Group, based in Shanghai, Harbin Power Equipment Corp, based in Heilongjiang Province, and Dongfang Electric Corp in Sichuan Province are the three power equipment giants.

The steam turbines at the Yuhuan power plant were jointly designed and manufactured by Shanghai Electric Group and Siemens Power Generation Group.

"Ultra-supercritical steam parameters enable the highest efficiency levels," says Lutz Kahlbau, president of Power Generation Group, Siemens Ltd China. "The country's development of environmentally friendly coal-fired power plants featuring this advanced technology shows that China is pursuing its policy toward clean coal power generation."

Another efficient power generation technology, called combined cycle, has also been adopted by China Huaneng Group.

In a combined cycle power plants natural gas or oil is used in a gas turbine to produce electricity. The exhaust gas is used to generate steam to drive a turbine.

The Huaneng Shanghai Combined Cycle Power Plant, jointly built by Huaneng Power International and Shanghai Shenergy Group at investment of 3.5 billion yuan, went into commercial operation in 2006.

The main equipment was jointly designed and manufactured by Siemens and Shanghai Electric Group.

As one of the projects developed in conjunction with west-east natural gas pipeline system, the plant has three 400-megawatts gas turbine combined cycle units, the first heavy-duty gas turbines in China, which aim to alleviate the peak power burden of Shanghai.

Gas turbine technology enables unit energy efficiency over 58 percent in combined-cycle power plants.

But some experts say natural gas-fired power plants should not be widely encouraged as natural gas itself is a clean energy. Turning it into electricity can be regarded as a secondary waste of clean energy.

"Proper proportion of developing natural gas-fueled power plants is necessary," disagrees Wang Jianlin, deputy general manager of Huaneng Shanghai Combined Cycle Power Plant. "As it is highly efficient and environmentally friendly, many developed countries have adopted such power plants ."

(China Daily 11/19/2007 page3)