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Professor Shinichi Iwamoto

Department of Electrical Engineering and Bioscience, Faculty of Science and Engineering, Waseda University

Q: Why are rolling blackouts the only option?

A: This was the only option.  We’re 10 million kW of power short and there’s no other way to balance the supply and the demand.  Blackouts happen when the running frequency drops.  Tokyo Electric power runs at 50Hz with a variation of plus or minus 0.2Hz.  If the frequency changes by more than 1Hz, the relay detects this, rejects the load, and causes an unexpected blackout.  To prevent this from happening, the company can only warn people and purposely cut power to certain areas.


Q: We’ve had power shortages in the past, but I remember it was just a matter of refraining from using some electricity.  Can’t we do that this time?

A: The amount of power we’re short of this time is much larger.  10 million kW is equivalent to 10 nuclear reactors producing 1 million kW of power each.  It’s not as simple as asking the supply and demand contract or site’s workers to come to a stop.

Q: How long is this going to go on for?

A: I think this’ll go on until the thermal power plants have started up again.  That means we’ll have rolling blackouts until the end of April.  It won’t be a normal stop and start, because the workers will need to check nothing has been damaged by the earthquake before re-starting the plants.  That’ll take much longer than usual.  Note that the thermal power plants account for 60% of the installed power generation capacity of TEPCO.

Q: What can we (people living in Japan) do to help?

A: The first thing that comes to mind that everyone could do is not to use the heater when it’s cold.  I’m 60 years-old now and I remember we didn’t have heaters when I was a kid, and every household was on a 10A contract.  But now every house has three to four heaters and 40 to 50A contracts.  If people could stop turning on heaters, it would help drop the demand of the electricity a lot.


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