Vulnerability of modern interconnected power grid networks

We no longer rely on our own private electrical generators. The major advanced regions of the world, such as North America and Europe, have a highly complex pattern of energy sources in power stations operating with a diverse range of technologies (from solar panels to hydroelectric, wind, coal, gas, and nuclear). Maps of electrical grid distributions over these regions look like complex spiders’ webs. Power flow is interconnected across wide regions, and adjusted to optimize performance with changing demands and available supplies. The system is sensitive: even minor change in output from one area can need careful adjustment to maintain full power across the whole region. For predictable daily demand, this is obvious, but less expected is that even the partial solar eclipse across Europe of March 2015 needed to be considered in forward planning, as it reduced solar power generation, which provides around 10 per cent of the electrical energy in central Europe. Economically, power generation is more profitable if there is a minimal spare capacity, so just a 5 or 10 per cent drop in supply at a high speed (i.e. from the moving shadow of the eclipse) cannot be rapidly compensated for by increasing output from other sources.

Mostly the power network works quite well, but nothing is infallible, and there have been numerous widespread power losses as a result of accidents, human errors, and excessive demands. In the last decade or so, greater interconnectivity has resulted in more people being affected by a power loss event. Mostly they have been relatively short term—on the scale of hours, or less than a day—but nevertheless they have caused major disruptions to large numbers of people.

A lightning strike on a substation in Brazil in 1999 caused a chain reaction of grid network collapse that hit 70 per cent of the country and affected 97 million people. Brazil has suffered other widespread electrical failures in 2009, 2011, and 2013. The north-eastern USA had power loss for four days in 2003 as a result of a combination of faults and human error that blacked out some 50 million people. Failures in other regions include one in Java in 2005 that hit 100 million people. So far the greatest number of people involved in a single power loss was from a power shortage in India in 2001, where there was power loss for 226 million. My sample of major incidents from a variety of causes underlines the claim that with ever-increasing demands, these power failure problems will be repeated many times in the future.

 
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