How long would the lights stay on?

[DaleCooper]

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).

A course in basic electrical theory is needed.

 

[The Decapod]

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

I assume that it wouldn't take long for people in France, Ireland or indeed the Isle of Man to realise that something catastrophic had happened here. Within a short space of time emergency forces from other countries would begin landing here, not least because they'd need to find out what had happened and do what they could to prevent any danger spreading to their countries.

 

[Sox]

The electricity transmission system is based on AC which cannot be stored, hence generation need to be very closely balanced with demand on an almost instantaneous basis. Too much generation and the frequency rises, too little and and the frequency falls (frequency is tightly controlled, 50Hz +/-1%).

With the sudden loss of grid control staff (i.e. someone to balance the system), the frequency will rapidly fall out of specification causing generating machines to automatically shutdown (the machines themselves are designed to operate within very specific frequency tolerances).

The synchronisation of multiple generation sets will rapidly be lost leading to cascade tripping, automatic load shedding and total system blackout.

I suggest a few minutes maybe ten/fifteen at most.

 

[Busaholic]

The answer has to be 42, or that trains would run to time at London Bridge and there was nobody there to record the fact.