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Japan's two incompatible power grids make disaster recovery harder

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


The huge disaster in Japan has ruined parts of the nation's electrical system, notably the six Fukushima Daiichi reactors that remain shut down. As a result, the country's utilities can't generate enough power to meet demand, so they are using rolling blackouts to give some power to everyone for some portion of each day. That tactic is crippling industry—it's hard to run a factory that makes cars or TVs when the power suddenly cuts out for a few hours each day. The blackouts complicate commuting, so workers can't get to their shifts on time, which further cripples manufacturing. And so on.

Incredibly, the southwestern half of Japan, which largely survived the earthquake and tsunami unscathed, cannot help the northeastern half of the nation, which took the brunt of the damage, because the two sections of the country operate on two separate power grids that are incompatible. As NPR reported on March 24, the southwestern section can actually produce surplus power, but the transmission and distribution system there operates at 60 Hertz, and the northeastern region's grid operates at 50 Hz. This awkward situation, seen clearly on the Japanese map above (blue is 60 Hz, red is 50 Hz), is the legacy of a historic oddity: the "east," as it's referred to in Japan, built its grid based on the German 50 Hz system, and the "west" followed the American 60 Hz system. (An English adaptation of a similar map is here.)

Converting power from one system to the other is a complex task that requires enormous yet highly sensitive machinery. The country has only a few, meager "interconnect" facilities that can do the job, which have nowhere near the capacity to minimize the need for rolling blackouts.


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The U.S. has a less dramatic but similarly tenuous setup. The nation is divided into three grids. All three operate at 60 Hz, but again, only a few interconnects exist between the regions. Those sites would have to be beefed up significantly if the country was to benefit from building massive wind farms in the windy high plains or big solar farms in the sunny southwest. More and larger interconnects would also allow regions to "wheel" large quantifies of power between them, to help minimize blackouts caused by storms. Better interconnects would also help utilities that might be in danger of exceeding their capacity (say, Texas, buckling under heavy air conditioning load in August) to get some extra power from another region that has some to spare (perhaps cool Minnesota on that same day).

Map courtesy of Tosaka, via WikiMedia Commons

Mark Fischetti has been a senior editor at Scientific American for 17 years and has covered sustainability issues, including climate, weather, environment, energy, food, water, biodiversity, population, and more. He assigns and edits feature articles, commentaries and news by journalists and scientists and also writes in those formats. He edits History, the magazine's department looking at science advances throughout time. He was founding managing editor of two spinoff magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 freelance article for the magazine, "Drowning New Orleans," predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. His video What Happens to Your Body after You Die?, has more than 12 million views on YouTube. Fischetti has written freelance articles for the New York Times, Sports Illustrated, Smithsonian, Technology Review, Fast Company, and many others. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti is a former managing editor of IEEE Spectrum Magazine and of Family Business Magazine. He has a physics degree and has twice served as the Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union's Robert C. Cowen Award for Sustained Achievement in Science Journalism, which celebrates a career of outstanding reporting on the Earth and space sciences. He has appeared on NBC's Meet the Press, CNN, the History Channel, NPR News and many news radio stations. Follow Fischetti on X (formerly Twitter) @markfischetti

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