Power to the people

A peak load power plant helps the Chinese seaport of Shanghai supply more than 12 million people with enough electricity to cope with a steadily improving standard of living.

DATE 2023-11-28 AUTHOR Zhang Lijia

A red telephone sits on a table in the office of the mayor of Shanghai. If his 12 million charges start using too much electric power, the mayor will use this emergency hotline in search of a man whose name means “For the People.”

Like many children of the 1950s, Guan Weimin was named in the proletarian spirit of Communist China’s early years. Half a century on, Guan Weimin, as director of the Shanghai Zhadian Gas Turbine Power Plant, helps the mayor keep this flagship city in electricity, as China transforms into an economic superpower.

Peak-load power used in extreme weather

“When the weather is extremely hot or cold, many factories, offices and homes turn on their air conditioners or heaters, and the city’s power load shoots up. We step in with emergency or peak-load power when generating units at other power plants break down,” says Guan.

The plant’s troubleshooting role is a far cry from even a decade ago. Guan recalls municipal authorities limiting power use or cutting power altogether in different areas and at certain times to avoid peak-load pressure. “Many workers had to go to work in three separate shifts, or – worse still – production sometimes stopped completely because the power went off. It doesn’t happen any more in Shanghai,” he says.

As their incomes rise, Chinese urbanites care more about comfort. Fewer factories require employees to work long hours, and more of the residents of China’s most cosmopolitan city are demanding the appliances taken for granted in the West.

Power consumption is increasing

“I can’t imagine my life without electricity,” says Jason Wang, chief representative for a British investment consultancy in Shanghai. The apartment he shares with his wife, just outside the city center, is equipped with air conditioners, a DVD player with a powerful sound system, a microwave oven and an electric heater.

“All the well-to-do families have these items,” Wang says. And all these items consume power. Over the past decade, the desire to keep up with the Wangs has fueled a surge in personal power use – from 15 percent of Shanghai’s total usage in 1990, to 25 percent last year, the highest ratio of any Chinese city. In the same period the overall demand for power in Shanghai has grown at an average of 20 percent each year, even outstripping the city’s

For over a century, the colonial-era architecture of the Bund, Shanghai’s riverbank promenade, has been the city’s foremost symbol. But today one must look across the water at the skyscrapers of Pudong, to the east of the Huangpu River.

A massive development plan has delivered a breathtaking scene of blinding reflections and wide avenues. The new stock exchange highlights the city’s status as China’s financial powerhouse. Vertigo sufferers should avoid the Grand Hyatt, the world’s tallest hotel, which starts on the 53rd floor and continues to the 88th.

The first gas turbine power plant

Powering this urban revolution are seven thermal power plants strung along the banks of the Huangpu. Yet even with their installed capacity of 9,100 megawatts, Shanghai still struggles during peak demand.

That’s where the eighth plant comes in – Zhadian, a heavy fuel oil burner, the first gas turbine power plant in the Shanghai region and the largest of its kind in China. Zhadian was built in 1995–1996 for 300 million U.S. dollars, a joint venture between the Shanghai government and General Electric of the United States.

“Our advantage is that once the plant is switched on, it reaches its full load within 25 minutes, while a traditional coal-fueled power plant takes up to 16 hours to reach full load,” says Guan. “We can cope easily with the sudden change in power load. Our plant is also far more environmentally friendly than a traditional coal-fueled plant. It is highly automated as well, so we can manage with only 80 staff.”

On a recent summer morning, four massive gas turbines, specially constructed for the Zhadian plant, were working flat out as temperatures soared to 37 degrees Celsius. Across the city people cranked up their air conditioners, dock workers sweated to pump fuel oil and tankers moved up the Huangpu to unload more oil. These ships dock in an oil treatment area where the oil is pre-conditioned using a range of Alfa Laval equipment.

Power pool instead of monopoly

As China’s entry into the World Trade Organization draws near, calls grow ever louder for the abolition of power market monopolies. A power-pooling experiment is under way in six regions, including Shanghai. In this experiment, plants can sell 10 percent of power generation through the pool to the open market during the first year of operation. In each subsequent year they can sell an additional 5 to 10 percent.

“We fully understand the importance of reform in the industry,” says Guan. “But we are in an unusual position. It’s not up to us how much power we produce. Though we cannot compete, we are needed for Shanghai, and that’s why we are subsidized by the government.”

“What we can do for now is to guarantee the high quality of our service and improve efficiency,” Guan says. For example, to re-use heat that is currently wasted, Zhadian will replace the current single-circle system with a combined-circle system consisting of four boilers and two steam turbines. Capacity should rise to 600,000 kilowatt-hours, and efficiency from today’s 30 percent to 50 percent.

As he navigates China’s changing economy, Guan Weimin is still working for the people.

Making sure the plant works, when it has to

A peak-demand power plant must function perfectly when needed. In order to remove fuel contaminants clogging up the system, Alfa Laval has equipped the spare gas turbine power plant in Shanghai with an oil separation system.

Gas turbines are under constant attack from the heavy fuel oils that feed them. Salt water, sand, scale and sludge are common enemies threatening to clog up the fuel system and cause power loss. Trace metals are even more vicious, corroding turbine blades. When a city the size of Shanghai depends upon your power plant’s reliability, you can’t make mistakes with contaminated fuel. Only the best treatment will do.

Tough competition

That’s the theory, though price naturally plays its part. In 1996, Alfa Laval went head to head with a German competitor for the contract to supply Zhadian with the centrifugal separators crucial to cleaning heavy fuel oils to the required standard. The competitor’s separator was cheaper than the Alfa Laval High Speed Separator but in spite of initial savings, the client chose Alfa Laval because of its ability to provide high quality service. Alfa Laval’s four sets of separators now take pride of place in the Zhadian oil-cleaning workshop. 

“It’s a good example of how our endeavour to pay high attention to service pays off,” says Yu Huihao, Energy and Environment segment manager, Alfa Laval (China) Ltd.

Trouble-free operation

By the time of the Zhadian sale, the firm already had a decade’s experience of promoting separators, plate heat exchangers and other products on the Chinese market. “I am proud to say there has not been a single case where production was interrupted because of our inadequate service,” says Yu. “We know that a power plant, particularly one that provides peak-load power, cannot afford any stoppages.”

Oil treatment system

Alfa Laval ensures trouble-free turbine operation by removing fuel contaminants or reducing them to acceptable levels for burning. High-speed centrifuges separate water and solids to isolate trace metals such as sodium and potassium that exist in the fuel oil as finely dispersed or emulsified droplets of salt water. Alfa Laval’s double-stage pre-conditioning system also includes pumping, water-washing and the addition of demulsifiers, after which sodium and potassium are reduced to less than one part per million.

“We are very happy with the oil treatment system,” says Cao Songran, the engineer responsible for spare parts and maintenance at Zhadian. “It is very reliable and well-designed, with attention to small details. Also, the service is very good."