151. INSTANT POWER BLACKOUT
Doomers often imagine a Hollywood like scenario where the oil runs out on Wednesday and the power grid fails on Thursday. By the following day everyone is chewing on the buttocks of the local populace.
The reality is quite different. Apart from the highly unlikely scenario of suddenly 'running out' of fuel to keep the power stations going, the grid system doesn't in fact tend to be quite such a hit a miss affair. Firstly, power stations are brought on and offline, thus allowing for breakdown and failure and to balance load. Second even in the event of power shortage governments tend to have plans to keep essential services working as far as possible. Generally major infrastructure such as oil pipelines, waterworks and hospitals are regarded as vital.
Current from power stations is stepped up onto grid voltages and transmitted across long distances. There are two types of grid: The transmission grid and the distribution grid.
For example, in the UK (England and Wales) the high voltage 400 kv 5800km 'supergrid' which moves bulk power supply around the country from power stations is run by National grid Transco and is under the supervision of the electrical controllers at their control centre near Wokingham, Berkshire.
The voltage is stepped down and then distributed by local electricity companies (EG EDF, Southern Electric) under the supervision of their electrical controllers to local consumers. Domestic customers receive a 240 v domestic supply, industry receives a higher supply voltage (usually 400 v) and electrified railways receive power at 25 kv or below (EG Network rail, London Underground) depending on the local arrangements. The bus bars of their feeder stations are controlled by their own controllers.
Switching is done via heavy duty circuit breakers, remote or manual switches on grid station bus bars and local distribution networks. Control is via mimic diagram or more usually SCADA (System control and Data Acquisition) workstations which oversee the state of the breakers and switches as well as load information.
You can even get some of this electricity demand information on-line.
The system is under constant supervision and customers can be switched in and out, in order to balance the loads in an emergency. If a tree falls on a power cable or it is stuck by lightning, or the load exceeds the rating of a circuit breaker, this usually results in a 'tripping'. The circuit breakers are opened automatically and in some cases alternative switching arrangements can negate the problem.
This is not to say the system cannot catastrophically fail, as it did on the 28th August 2003. The official report is here.
But the grid falling over on a permanent basis or cutting vital customers off because of fuel shortage is an urban myth.