Earthquake disrupts Japan’s thermal power operations

A powerful earthquake hit wider areas in Japan's Tohoku and Kanto regions late on 16 March, causing a shutdown of around 6.5GW of thermal power and leading to tighter electricity supplies.

A 7.4 magnitude earthquake jolted offshore Fukushima prefecture at 23:36 local time on 16 March. This led to a tsunami warning for a sea level rise of up to one meter in the two most-affected prefectures, Miyagi and Fukushima, with the warning lifted by 5:00 on 17 March.

The earthquake had immediately shut five gas-fired units with a total capacity of 2.34GW, eight coal-fired units with a total capacity of 3.71GW and one 431MW oil-fired unit, according to data from the Japan Electric Power Exchange (Jepx) and the trade and industry ministry (Meti). The quake also closed several hydropower plants in the Tohoku area. This temporarily left up to 2.2mn households in the Tokyo and Tohoku regions without electricity, with several areas in Tohoku still suffering blackouts.

Utility Tohoku Electric Power's 523MW Shin Sendai No.3-2 gas-fired unit and refiner Eneos' 431MW Negishi oil-fired unit were already brought back on line, while Hitachi Zosen's 112MW Ibaraki Daiichi gas-fed unit and the 523MW Shin Sendai No.3-1 gas-fed unit are likely to resume operations today. Nippon Steel's 136MW Kamaishi coal-fired unit and Nippon Paper's 149MW Ishinomaki Hibarino coal- and biomass-fed unit are also expected to restart within the next few days.

But it remains unclear when the other thermal units, with a combined capacity of 5.13GW, will be restored. These include major coal-fired units, Tohoku Electric's 1,000MW Haramachi No.1 unit, Soma Kyodo's 1,000MW Shinchi No.1 unit, and Jera's 600MW Hirono No.5 and No.6 units. Separately, Tohoku Electric and Jera are also checking for any damage sustained by the coal-unloading terminals.

The shutdown of the Haramachi No.1 unit has halted all operations at the coal power plant as Tohoku Electric's 1,000MW No.2 unit is undergoing maintenance from 5 March to 3 July. Soma Kyodo was also forced to entirely shut its Shinchi coal-fired plant, which supplies electricity to Tohoku Electric and Jera, as its 1,000MW No.2 unit has been closed since 12 March because of a technical issue.

Regional power grid firm Tohoku Electric Power Network asked for power supplies from fellow grid firms Hokkaido Electric Power Network and Tepco Power Grid through the Organization for Cross-regional Coordination of Transmission Operators' support scheme, to secure up to 1.4GW during 2:30-6:00 and 1GW over 6:00-11:00 on 17 March. Electricity supply conditions in Tohoku have improved since then, with the area expected to have a 13pc surplus in power supply for 17 March.

Japan's northeast area had experienced a devastating earthquake, subsequent tsunami and nuclear reactor meltdown in March 2011. The area was also hit by a powerful earthquake in February 2021. No severe damage to the closed nuclear reactors in eastern Japan was reported following the 16 March earthquake.

By Motoko Hasegawa