Royal Astronomical Society Press Release
RAS PN 10/30 (NAM 15) 14 April 2010
Changes in the space environment caused by the Sun can lead to periods of bad “space weather”. As well as driving intense displays of the northern lights (or aurora borealis), this can generate unexpected currents in electricity distribution grids that could lead to blackouts and damage to valuable infrastructure with potentially high cost to the global economy.
Bad space weather can cause fluctuations in the Earth’s magnetic field (geomagnetic storms) that lead to Geomagnetically Induced Currents (GICs) in power grids. These currents have previously been blamed for blackouts in Canada and Sweden and are suspected of damaging power transformers in countries at lower latitudes. Large GICs have even been recorded in Scotland.
To prevent future blackouts, understanding how GICs occur is vital. The model developed by the British team, the most sophisticated yet developed, takes magnetic field measurements from all over the UK and combines them with the BGS’s 3D model of how the ground beneath the UK conducts electricity, in order to estimate the currents induced at over 250 locations in the high voltage national grid.
The new work provides further evidence that the size of the unwanted current depends not only on the severity of the geomagnetic storm but also on the configuration of the power grid and the direction and fluctuation speed of the electric fields produced. For many years, it was thought that only countries located at high latitudes (near to the Earth’s magnetic poles) were at risk, but this is now known not to be the case. While the basic physics that links solar activity to our electricity grids is broadly understood, the interaction between natural and man-made systems makes it hard to quantity the risks.
Bad space weather caused by high levels of solar activity can
impact on power grids here on Earth. (Turnbull/Wild/ESA)