How long would the lights stay on?

Discussion in 'General Discussion' started by The Crab, 14 Aug 2015.

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  1. The Crab

    The Crab Member

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    I think there are a few people from the power industry on this forum so maybe they could give a clue about something I have often wondered.

    Just suppose that everyone in the country dropped dead at midday today - how long would the National Grid supply electricity?
     
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  3. gazthomas

    gazthomas Established Member

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    Would we need lights?
     
  4. DarloRich

    DarloRich Veteran Member

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    no - but they would surely stay on for a period even if everyone simply disappeared at noon
     
  5. GrimsbyPacer

    GrimsbyPacer Established Member

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    Is this because of triffids and the meteor shower?
    Anyway, I'd guess the wind turbines will keep on running til gale force winds damage them in operation, the coal plants will last upto a day with coal supplies if on full power, the nuclear plants will blow up if the coolant water isn't replaced and solar will work until covered by dust and dirt. Lights don't need much power usually between 7&100watts depending on type, so I bet some will be on for decades afterwards in the event of this disaster regardless of what the movies say. Lights won't stay on long though if everyone was watching Telly with the heating and cooking on when they died as the power supply would be too far stretched.
     
  6. edwin_m

    edwin_m Veteran Member

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    Schroedinger's fridge - if the door is shut then how do we know if the light is on or off?
     
  7. DaleCooper

    DaleCooper Established Member

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    With no human activity it wouldn't take long for vegetation to start interfering with infrastructure. It would only need to start knocking out circuit breakers in substations or bringing down overhead cables and with nobody to repair the damage that would be that. Look how quickly plants engulf abandoned buildings and break through roads. I reckon in about 50 years all that would be visible of cities would be a few of the taller buildings poking above the trees. All that's before you add in the effects of weather.
     
  8. causton

    causton Established Member

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    A good fridge turns the light off when the door is shut! :D
     
  9. DaleCooper

    DaleCooper Established Member

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    How do you know?
     
  10. Clip

    Clip On Moderation

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    Mine beeps everytime the light is on.














    It doesn't really
     
  11. DaveNewcastle

    DaveNewcastle Established Member Fares Advisor

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    no UK nuclear reactor will continue to burn fuel in the absence of an active supply - the fuel simply falls out of the reactors.
     
  12. DaleCooper

    DaleCooper Established Member

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    Stick to law.
     
  13. DaveNewcastle

    DaveNewcastle Established Member Fares Advisor

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    The fuel rods in the AGRs are held in position by electrically operated clutches so that in the absense of line voltage, they are released. In that event, gravity does the work of swiftly removing them from the vessel.
     
  14. tony_mac

    tony_mac Established Member

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  15. DaleCooper

    DaleCooper Established Member

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    It appears that it's the control rods that are held by clutches so they drop into the reactor to absorb neutrons and stop the reaction.
     
  16. beermaddavep

    beermaddavep Member

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    Dropping the fuel rods out of a reactor, away from the moderator core, coolant and the control rods? You certainly wouldn't need to worry about any lights being on if that happened!

    Back to the op, I doubt that the lights would stay on for long at all, probably hours rather than days. Power stations need people to run them, yes they are automated but the automation and instrumentation is nowhere near as reliable as outsiders might think. Regular intervention is needed by the control room panel operators, without which stations would simply 'trip out' or shutdown. Even the very best set up still requires human intervention around the plant to keep it running- filters choke up and need to be changed, oil and grease must be topped up, boiler feedwater dosing tanks need to replenished, leaks spring, pumps fail, instrument air compressors fail, relief valves stick, control valves stick, instrument tappings choke up etc etc. Somebody needs to drive the shovels that load the coal!
     
  17. asylumxl

    asylumxl Established Member

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    This would be correct. Modern reactors are designed with many failsafes in them for obvious reasons. Torness is a particularly impressive AGR design. Unfortunately, most governments since have opted for more conventional designs.

    More on topic, are we to assume the folks in control of the grid also drop dead?
     
  18. ExRes

    ExRes Established Member

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    The thing that concerns me the most is that H&S would not be able to look after the rights of all those that have died, because they'd be dead as well ........

    :o
     
  19. Clip

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  20. DaleCooper

    DaleCooper Established Member

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  21. tony_mac

    tony_mac Established Member

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    From what I read, they didn't go onto the island itself, but used a studio set based on it in Skyfall.
    I haven't seen either film.
     
  22. DaleCooper

    DaleCooper Established Member

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    From IMDB again (Skyfall)

    which according to Wikipedia is commonly called Gunkanjima (meaning Battleship Island)
     
  23. The Crab

    The Crab Member

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    Thanks to all who have contributed.

    Any answers to the following (ignoring breakdowns):

    1. For coal fired stations would the deciding factor be actually getting the coal stocks close enough to the conveyors (I assume that is how they work)? How does this actually work?

    2. In the case of oil, could all the stocks on site be used automatically?

    3. I would guess that gas would be the easiest to continue working so long as gas is being delivered. How likely is it that the North Sea supplies would continue with all the operatives dead? Ignore other supplies as I have not decided whether the rest of the world is dead.

    4. In the case of very large consumers such as the steel industry, would demand wind down as each process was completed?

    5. Grid management. As various generating unit go off-line, would the grid try to rebalance supply? Would it cut off areas in the country to maintain quality of supply to the remainder? Is it right that as power generated fails to meet demand the frequency falls? What happens automatically if the frequency falls significantly below 50Hz? What would make the grid fall over completely even though a significant amount of power is still being generated? In the case of hydro or wind, can the grid isolate supply and demand to the local areas?
     
  24. me123

    me123 Established Member

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    1) Take your Smartphone.
    2) Open the video app.
    3) Press record.
    4) Insert smartphone into your refrigerator. Ensure that the camera lens is not obscured.
    5) Close the fridge door.
    6) Wait five seconds.
    7) Open the fridge door.
    8) Remove smartphone.
    9) Stop recording.
    10) Review footage.
    11) Upload video to Youtube for posterity.

    [youtube]q92iQ49F0IM[/youtube]

    (PS: Tongue is firmly in cheek :p )
     
  25. edwin_m

    edwin_m Veteran Member

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    But do we know that for sure? Should we stick a smartphone in your mouth?
     
  26. me123

    me123 Established Member

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    My mouth isn't actually that big (although I've been told otherwise on numerous occasions!), but if you want to send me one of these I'll happily upload the evidence ;) (Don't worry, I won't swallow it and subject you to the full experience!).
     
  27. Peter Mugridge

    Peter Mugridge Established Member

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    Surely a much quicker and lower hassle way of testing it is to simply press down the door activated switch with a finger and see if the light goes off or not...?:lol:
     
  28. cb a1

    cb a1 Member

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    Surely you know that button only exists to make people think the light goes off when you close the door.

    Modern fridges are also equipped to deal with smartphone methods and switch themselves off if they detect a recording device within them.

    Unfortunately all models are equipped to detect when people remove all the shelves and climb into the fridge to see for themselves.

    I read all about it somewhere on the internet, so it must be true.
     
  29. Clip

    Clip On Moderation

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    that's what I meant Skyfall. Turns out that was wrong too. Looks very much like it though
     
  30. Mojo

    Mojo Forum Staff Staff Member Administrator

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    That is exactly what I was thinking.
     
  31. RailAleFan

    RailAleFan Member

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    Interesting question.

    A fundamental part of managing a power grid is the balancing of supply and demand. Energy cannot be created or destroyed, only converted from one form into another, so once electricity has been generated it has to be used pretty much straight away, and if "we" don't use it, then nature will take over and use it the way nature understands best (fire).

    So it wouldn't just be a case of if everybody in the world suddenly dropped dead at midday how long would all feed-ins to the grid carry on producing electricity until they individually ran out of fuel, but also at what point would the difference between supply and demand exceed the envelope within which the system is designed to operate autonomously and starts to shut itself down gracefully, but not only that, there will be the equivalent of the "dead man's handle" in place throughout the system.
     
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