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How is Japan generating electricity

  1. Apr 27, 2012 #1
    With all but one of the Japanese nuclear plants offline (and the last one due to shut down in early May), how are the utilities continuing to meet demand? I read in various places statements such as "Japan has been importing unprecedented
    amounts of coal, oil and natural gas, resulting in rising costs for consumers as
    well as rising carbon emissions."

    I wonder, where is this coal, oil, and nat gas coming from? What proportion of these fuels is being used? And mostly, I wonder where it is being burned. I understood that the 50 some nuclear units had been providing 30 to 35% of the electric generation. Did Japan really have that many idle coal, oil, and gas-fired units that were not being run when the nuclear units were on line? I suppose most of this capacity had been available for peaking; what is going to happen when the peaks come this summer and all of the units are already maxed out meeting the base load?

    Sorry if this is really not a 'nuclear engineering' question, but it seems most readers interested in the ongoing events in Japan might be found here.
  2. jcsd
  3. Apr 27, 2012 #2


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    Clearly the loss of nuclear generation is a consequence of the Fukushima event.

    Rise in Oil Imports Drives a Rare Trade Deficit in Japan

    Some background on Japan's involvement in the Middle East.

    But Reuters reports http://www.reuters.com/article/2012/01/25/energy-japan-mof-idUSL4E8CP0IZ20120125 =
    Jan 25 (Reuters) - "The volume of Japan's customs-cleared crude oil imports in 2011 fell 2.7 percent from the previous year to a 22-year low, the Ministry of Finance said on Wednesday."

    However, "liquefied natural gas imports hit a record high last year both in terms of volume and value, as the nation significantly boosted gas-fired power generation to offset a sharp fall in nuclear power plant utilisation rate following the Fukushima disaster."

    One may need to find the Ministry of Finance (or METI) website or alternatively, peruse the websites of individual utilities.

    It seem they boosted utilization of gas turbine (LNG) generation as well as calling for reduction in consumption.

    I seem to remember that the nuclear generation capacity factor was historically relatively low, < 70%.
    Last edited: Apr 27, 2012
  4. Apr 27, 2012 #3
    Here you have Tepco's data on fuel consumption and purchase: There seems to be a general increase for Fuel Oil (+78%), Crude Oil (+54%), LNG (+17%) and Coal (+7%) compared to the previous fiscal year.

    But Kanto, region where Tepco operates, had less dependence on nuclear generation compared to Kansai, for example (I have seen numbers indicating 50% of energy supply being generated by nuclear in that region, but I have nothing solid.)

    And here is an article reporting on the potential power shortages next summer.
  5. Apr 28, 2012 #4
    Load shaving generators are usually oil/gas/coal. But you can run them as primaries which is what they are doing.
  6. Apr 28, 2012 #5


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    Japan lost electric generating capacity. However the full capacity is used only during demand peaks (hot summer evenings, for Japan), so that this is a problem only in summer at those times of the day. At present it is probably still OK. The region where the capacity problem is most severe is Kansai as it used to rely on nuclear power for about 40%.

    The Meti website at http://www.meti.go.jp/ (top right part of the screen) has a real time display of electric demand in percentage of capacity for 4 main utilities (Tohoku El. Power, Tepco, Kepco, Kyushu El. Power).

    See also "Predictions of summer power shortages may be inaccurate" at http://ajw.asahi.com/article/0311disaster/fukushima/AJ201204070047 [Broken] where http://dwqovw6qi0vie.cloudfront.net/article-imgs/en/2012/04/07/AJ201204070047/AJ201204070048.jpg [Broken] reveals that more hydro pumped-storage capacity may be available than officially acknowledged by Kepco. Of course pumped-storage is not a very efficient way to use oil... and Kepco might want to avoid that.

    I know you are asking about what is going on now in 2012, but on 17 March 2011, it was reported that "South Korean companies are also making emergency shipments of gasoline, diesel and kerosene to Japan, after refineries in Japan scaled back operation following last Friday’s earthquake". Korea also sent boric acid : http://blogs.wsj.com/korearealtime/2011/03/17/seoul-helps-japan-in-cooling-down-reactors/
    Last edited by a moderator: May 5, 2017
  7. Apr 29, 2012 #6
    Japan had rolling blackouts last summer, due to the loss of nuclear capacity. They are just now restarting their nuclear plants, and should have capacity to run brownouts (constant power, but lower than normal voltage) at the least over the summer. The energy minister once again is saying rolling blackouts and no industrial large users being fed power are likely this summer. http://articles.marketwatch.com/2012-04-25/economy/31397837_1_japan-s-fukushima-nuclear-reactors-usage-cuts [Broken]
    Last edited by a moderator: May 5, 2017
  8. May 2, 2012 #7
    To be pedantic, Japan implemented rolling blackouts in the first few weeks after the earthquake. By April 8th the rolling blackout program had stopped. It actually stopped prior to the 8th, but Tepco calculated power consumption daily, and they apparently felt confident enough to "cancel" the planned blackouts for the closing days of March. By April the power situation was stable enough so that they could officially claim an end to the planned rolling blackouts. There were no more blackouts after that.

    http://www.yomiuri.co.jp/atmoney/news/20110408-OYT1T00436.htm [Broken]

    Japan brought old power plants (non-nuclear) online, and they increased shipments of fossile fuels as mentioned above. They are not restarting their power plants yet. There is only one online, as far as I know, in Hokkaido. Edano said in his comments that rolling blackouts might be necessary if temperatures are above normal.

    The word on the street here in Japan is that the government continues to foment unease about power supply in order to create a more sympathetic environment for nuclear power. This is of course just chatter on the street. Take it or leave it as you see fit.
    Last edited by a moderator: May 6, 2017
  9. May 2, 2012 #8
    Gary7, if they blacked out industrial users, would you have noticed?
  10. May 2, 2012 #9
    I'd expect them to blackout the population first and the industry second and only when they can't compensate with private blackouts.

    If you blackout private citizens, you get annoyed people who complain that their PS3 and air condition aren't working.
    But if you blackout the industry, as a government you're actively decreasing your tax income and probably detering investors. Why building a factory where the infrastructure is bad (and blackouts are a sign of bad infrastructure)?

    What I'm trying to say: If the normal population didn't spot any blackout, then it's very likely that the industry didn't suffer any blackout either.
  11. May 4, 2012 #10
  12. May 4, 2012 #11
    From that article: "Japan managed to get through the summer last year without any blackouts by imposing curbs on use in the immediate aftermath of the earthquake and tsunami. Factories operated at night and during weekends to avoid putting too much stress on the country's power grids. A similar success this year would weaken the argument of proponents of nuclear power. "

  13. May 9, 2012 #12


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