Friday, 21 October 2011

Cyber attacks on power grids - how they can happen

One often hears about the possibility of electricity grids being blacked out by cyber attacks but until coming across an article in the Financial Times (Oct 12) I was not sure how this might happen. 

An electricity grid, such as the UK’s National Grid or various regional grids in the USA, comprises a network of power stations connected by very high voltage cables. Houses, corporations and public service all depend on the electrical power distributed by the grid.

 The essence of a power station is

  • A source of heat, be it the burning of fossil fuels (gas, oil or coal) or the splitting of atoms (nuclear).

  • A boiler to provide super-heated steam.

  • A turbine which rotates as the steam is fed into it.

  • A generator comprising coils of copper wire in a magnetic field.

The rotational energy of the turbine causes the wires of the generator to be rotated through the magnetic field and this induces an electric current in them. It is this current which is fed into the grid.

So how is this system susceptible to cyber attacks? The answer appears to be in the turbine control unit which governs the speed of the turbine. If malicious data gets into this control unit the turbine blades can rotate too fast and be damaged or completely destroyed, which means no power. When these control units are part of an electronic network which is connected to the internet they are vulnerable to hackers hell bent on sabotage.

There are of course measures to counteract such attacks and many power stations are not connected to the internet, although even these could be affected by personnel with direct access to the turbine control units. The problem is that the security people are in a kind of arms race with the hackers, so that our domestic, corporate and public electricity supplies are dependent on the security programmers winning this race as well as on thorough vetting of power station staff by employers.

A recent survey indicated that 85% of the world’s utility networks have been infiltrated by criminals and spy agencies. In a way you could say this is encouraging because despite the infiltrations no serious widespread black outs have occurred but nevertheless I hope there is no relaxing of vigilance.

Author, 2077 AD