Nicholas Lewis
Established Member
National Grid plan the production of electricity hour by hour and to keep "the lights on" they consider credible failure scenarios such that if they occur they wont result in a power cut. Thus the grid is resilient to one complete power station or interconnector dropping off the system or loss of a key transmission line such that there is no loss of supply anywhere. This does happen on a fairly frequent (several times a year) basis and the lack of power cuts is testament to NGs planning. NG deal with this by having units on the system part loaded that can rapidly pick up load as well as using batteries now that there is so much less system intertia now the coal fired units have been shut down. The big coal sets(500-660MW) have a lot of rotational energy because of the mass so they could help for several seconds whilst other generators respond to the need to increase output. The other thing NG have to contend with is generators have plant outages and can't generate also the transmission system can have failures although this time of year they wouldn't allow any planned maintenance. So when they say there is a blackout threat what they are really saying is the probability they can cope with an unplanned failure is reduced but it would be a unique set of circumstances that would have to conspire. But as Murphy's Law says if it can happen it will so best to warn people.
