Japan's Hokkaido Electric shuts 600 MW coal-fired unit as earthquake hits

Japan's Hokkaido Electric shut its 600 MW No. 2 coal-fired unit at the Tomato-atsuma power plant unexpectedly at 18:55 local time (09:55 GMT) on June 11 around the time when a major earthquake rocked nearby offshore Urakawa.

In a June 11 updated filing to the Hatsuden Joho Kokai System, Hokkaido Electric said the shutdown was triggered by the earthquake. The company added it plans to restart the plant on June 11.

A magnitude 6.2 earthquake rocked nearby offshore Urakawa at 18:55, according to the Japan Meteorological Agency.

On June 9, Japan decided to undertake voluntary electricity savings in the Tokyo area over July-August amid a severe summer supply and demand outlook.

The Tokyo area's reserve power supply capacity ratio is expected to be only 3.1% in July due to extended repair works at some power plants.

The Ministry of Economy, Trade and Industry earlier has said that the Tokyo area has secured a 3.1% reserve power supply capacity ratio over the 10-year high demand in July, just above the minimum requirement of 3%.

For August, the Tokyo area is now expected to have a 4.8% reserve power supply capacity ratio, with September at 5.3%, well below the reserve power supply capacity ratio of around 10% secured for the western Japan over July-August, METI said.

The unexpected outage of Hokkaido Electric's 600 MW No. 2 coal-fired unit at the Tomato-atsuma power plant could deteriorate Tokyo's already severe-looking summer power supply and demand balance because Hokkaido Electric's electricity supply contributes to Tokyo area's integrated reserve power supply capacity ratio.

The outage of the baseload coal-fired unit could also affect Hokkaido Electric's use of other thermal power generation fuels such as LNG and fuel oil during the summer demand month should it last a long time.