After the Fukushima nuclear disaster, the utility company Tepco faced a problem: how to keep the lights on with the reactors off? Four of my students (Dan Bodley, Andrew Boudreau, Allison Dee, and Nick Phoutrides) found the answer. It boils down to “they didn’t.” But why they didn’t turns out to be very interesting. Preview: it was not because the nation of Japan lacked the excess capacity to replace nuclear electricity.
Japan is divided into 10 different utility areas.Tepco enjoyed 65 GW of capacity (17 from nuclear) and imported up to 13 GW. Typical summer peak demand ran around 61 GW. The quake took 17 GW of nuclear off-line, leaving 48 GW of local capacity under the heroic assumption that the utility could run all its non-nuclear plants at peak capacity.
Except there were two problems. First, the quake bady hit Tohoku — which normally provided all of Tepco’s imports — even worse than Tepco.
The second problem was the “frequency frontier” that ran roughly along the border between the Tepco-Tohoku service areas and the Hokuriku-Chubu service areas. Back when Japan first electrified, in the 19th century, General Electric supplied the Osaka utilities whereas the precursors to Tepco bought from Allgemeine Elektricitäts-Gesellschaft. AEG ran its equipment at 50Hz, whereas G.E. used 60Hz. The end result was the “frequency frontier” that bisects the country. There were three converter stations on the frontier, but their combined capacity came to only 1.2 GW. The end result was that Tepco’s maximum available peak import capacity declined from 13GW before the quake to only 7.3GW ... and that 7.3GW number, remember, was a maximum.
In short, Tepco faced a peak shortfall of 5.4 GW. Here is how that worked out: 47.7GW non-nuclear supply + 7.3GW imports − 60.4GW peak demand = (5.4GW). Tepco filled the gap by “conservation.” Why the scare quotes? Well, we normally think of conservation as turning off the AC, keeping lights low, taking the stairs, that sort of thing. We do not think of rolling blackouts as conservation. But rolling blackouts are indeed how Tepco reduced demand. In fact, Tepco exported 1.4GW to Tohoku in August 2011.
Running the company’s thermal plants at full speed meant importing a lot of liquified natural gas (LNG): Tepco’s imports jumped from 959 BCF in 2010 to 1,127 BCF in 2011. Fortunately for Tepco, its LNG facilities had a capacity of 2,785 BCF.(Of that, Tepco wholly owned two terminals capable of producing 1,287 BCF, with another 1,377 BCF of capacity in two terminals co-owned with Tokyo Gas. Tokyo Gas is the sole owner of the fifth; the gas company imports about 560 BCF per year in total.)
2012 appears to have been little different from 2011. Demand peaked at 50.8GW; Tepco had a cushion of 3.8GW on imports peaking at 6.9GW. But demand was held to 50.8 only by dint of blackouts. LNG imports remained about the same, at 1,120 BCF.
And so there you have it. On paper, Japan could handle taking nuclear off-line almost as easily as Germany. In practice, not so much, because of decisions made a century ago about sourcing electrical equipment from Germany and the United States. Economic history, it is an awesome field.