Rolling blackouts as Japanese efforts continue

14 March 2011

Japanese utilities are introducing rolling blackouts in the face of energy shortages following the natural disasters of the last few days. Meanwhile, the country is relying more than ever on the continued operation of its other nuclear reactors.

With few natural energy resources, Japan is highly dependent on its 54 nuclear reactors. Eleven of those nuclear units are now out of action in the wake of the 11 March earthquakes and tsunami. Some reactors, including three at the stricken Fukushima Daiichi plant, the two units at Hokuriku's Shika plant, Chubu's Hamaoka 3 and Tohuku's Higashidori 1 were already offline for routine outages when the earthquake struck. In total then, including those plants that were already offline at the time of the earthquake, some 13,360 MWe of Japan's installed nuclear capacity of just over 47,500 MWe is out of action. However, nuclear reactors at Japan's other sites are still working safely and providing vital power.

Although nuclear energy supplies around 30% of Japan's electricity, the country generates around twice as much power from fossil fuel power stations, relying on imported LNG, oil and coal. Hydroelectricity also provides a vital contribution – around 7.5% of its annual generation.


All generating options have suffered impacts from the events of 11 March, and Japan's Ministry of Economy, Trade and Industry (Meti) announced on 13 March that it would take steps to suppress power demand from industry. Japan's largest utility, Tokyo Electric Power Company, has seen its capacity heavily hit by the earthquakes, and introduced rolling blackouts of three hours at a time from 14 March.


For 15 March, Tepco estimates it will face an electricity demand of around 37 GWe against an available supply of 33 GWe.

Soon after the earthquake on 11 March, Tepco reported that 12 of its thermal power units and 22 hydroelectric plants had ceased operations because of the earthquake. Later that day, about 2.4 million households in its service area were without power. By 3pm on 13 March all the hydroelectric plants were back online, but nine thermal units totalling about 6750 MWe of capacity remained out of service from the company's total thermal capacity of just over 38,000 MWe. 260,000 households were still without power.

The Niigata-Chuetsu-Oki earthquake of 2007, which saw Tepco's Kashiwazaki Kariwa nuclear power plant taken offline for two years, resulted in an estimated cost of $5.62 billion to the company. Increased fuel costs to replace the 8000 MWe of lost capacity accounted for an estimated 75% of that total.

Researched and written

by World Nuclear News


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