There is no way to catch them all! Why are power plants so afraid of "jellyfish infestations"?

A bumper harvest of jellyfish brought an unexpected incident to a power plant.

"We can't catch them all. We can't catch them all. It started on September 18. The power plant hasn't encountered such an emergency in more than 30 years."

This is a call for help from Zhejiang Energy Jiaxing Power Plant: In the past few days, this old power plant, which was officially built in October 1994, has suffered an infestation of jellyfish, causing the rotating filter in the plant's circulating pump room to overload and malfunction, and employees have to catch jellyfish 24 hours a day.

How many jellyfish are there? From September 18 to September 25, a total of about 5,250 bags, weighing 210,000 kilograms, of jellyfish were caught.

On September 26, the same scene was still played out. A large number of employees were still standing in front of the rotating filter to clean the jellyfish, and the jellyfish under their feet had piled up into a "small hill".

Relevant staff of Zhejiang Energy Jiaxing Power Plant said that although everyone is doing their best to reduce the impact of jellyfish infestation, the situation is not optimistic: "We especially hope to brainstorm and see if there is any way to solve the jellyfish problem."

Photo provided by the interviewee

Where do jellyfish come from?

Why are power plants so afraid of it?

Where do so many jellyfish come from?

"It came with the sea water. We have learned that a similar situation has occurred in a power plant in Shanghai." Xi Chao, deputy director of the power plant's maintenance department, told reporters that the power plant is close to Hangzhou Bay and the East China Sea, and due to multiple factors such as the weather, this year's jellyfish harvest is rare in decades.

During the operation of the power plant, seawater from Hangzhou Bay needs to be pumped in for cooling the generator sets. This step is essential every day.

When seawater is pumped into the rotating filter, the filter will isolate debris, and the filtered seawater is then pumped into the generator set to ensure the unit's power generation capacity.

"Under normal circumstances, the rotating filter is stationary. It is activated every four hours for 15 minutes each time to clean the debris attached to the filter, including small fish, shrimps, jellyfish, etc. that come with the seawater. The failure frequency does not exceed two or three times a year. But this year, there are too many jellyfish that come with the seawater. They stick tightly to the filter and block the filter. On the one hand, it causes the filter to overload and trip, and on the other hand, it blocks the seawater channel. We have to keep the rotating filter running 24 hours a day."

Even when the machine is forced to rotate 24 hours a day, the filter is automatically flushed and manually cleaned, the effect is still not ideal: "The reducer support is pulled and cracked, the screen is deformed and stuck, and the shear pin of the rotating filter breaks. The machine has an average of eight or nine failures a day."

From September 18 to September 26, there were more than 100 failures of the rotary filter, far exceeding previous years.

On the evening of September 25, Xi Chao rushed to the power plant from his home in Jiaxing. "Starting at 7 o'clock in the evening, a large number of jellyfish suddenly poured in. Only one of the six rotary filters in the third phase circulating pump room could operate. One of the two 1 million generators was forced to shut down, and only one could operate. The power generation capacity of the power plant was reduced." Xi Chao said that this was the biggest emergency incident that had occurred in the power plant since the jellyfish incident.

Cleaning jellyfish with bare hands. Photo by Yu Liudong

Blocking, filtering or other,

What to do next?

It was late, but inside the Zhejiang Energy Jiaxing Power Plant, there were still many people wearing safety helmets gathered in twos and threes, and the work of catching jellyfish in front of the rotating filter had not stopped.

This is a tough battle.

At night, more technicians stay behind. They have to stay on duty to prevent the jellyfish from having another blowout as the tide changes, causing the machine to overload and malfunction. They have to repair it in time to ensure regular power generation.

"The generators cannot be stopped at will, and there are prescribed limits on unplanned downtime each year. For us, this is a rather serious matter," Xi Chao said.

"At the beginning, we were quite optimistic. We cleaned up 600 bags of jellyfish on September 18, 500 bags on September 19, and 450 bags on September 20. We thought that the amount of jellyfish would gradually decrease after a few days, but we cleaned up 1,350 bags on September 24 and 1,000 bags yesterday." Xi Chao said that the impact of jellyfish has lasted for more than a week. It is impossible to predict the trend of the jellyfish crisis based on the data, and no one knows when it will end.

Jellyfish bring "crisis" to power plants. Photo by Yu Liudong

The workers had to "fight" all night. Photo by Yu Liudong

Photo provided by the interviewee

The power plant is actively looking for ways to save itself and has also contacted marine experts, the Pinghu Municipal Government, etc.

"For now, we can only catch them manually. We have also received some useful suggestions, such as trying to build an anti-fouling net in the relevant sea area to prevent some jellyfish from entering."

"We can only respond with the most sufficient manpower and the most complete arrangements." Xi Chao said that he also hopes to find various ways through the media to "minimize the impact of the jellyfish crisis."