Jellyfish clogging Japan's thermal power plants in Ise

Close to 24,000 tonsof Jellyfish have been swarming near nine thermal power plants on Ise Bay.

Chubu Electric Power Co. is taking measures to ensure the jellyfish don't clog the power plants' water intakes and disrupt their operations.

They discovered that most jellyfish larvae transform into polyps in three major areas: near the port of Nagoya; along the coast of the Chita Peninsula from Tokoname to Morozaki, Minamichita, in Aichi Prefecture; and along the coast of the Shima Peninsula from Matsusaka to Toba in Mie Prefecture.

"We don't know the reason why the number is so high this year, but we need to monitor the situation closely," said Minoru Hamada, 46, an assistant project manager in Chubu Electric's technology development department.

If jellyfish block the water intake, a power plant can't draw enough water from the sea to cool the steam used to turn the turbine, and the plant has to reduce its electricity output.

Each plant has adopted various measures, including putting up nets, to stop the jellyfish from swimming too close, but this is only effective when dealing with small numbers. It is not enough to prevent large amounts of jellyfish from swimming in all at once.

The number of jellyfish started gathering around the plants in May, resulting in reduced electricity output at the Hekinan plant in Hekinan, Aichi Prefecture; the Shin-Nagoya plant in Nagoya; and the Kawagoe plant in Kawagoe, Mie Prefecture.

"The effect of the jellyfish isn't fully known yet, but it can have a serious impact on electricity output if they keep increasing, especially during this season when there is high electricity demand," a Chubu Electric official said. "We need to monitor the jellyfish further and take actions swiftly if necessary."

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