Blackouts Ahead on Our Unruly Power Grids

ImageTen years after the Northeast Blackout that shut off power in seven U.S. states and Ontario cascading power grid failures remain a fact of life. And, as I argue today on Spectrum’s Energywise blog, engineers are little closer to predicting and preventing them.

The good news is that engineers are beginning to accept that they have a complex system problem on their hands — an insight that could help them find solutions.

Such understanding was in short supply one year after the Northeast blackout, as I discovered with the publication of my August 2004 cover story for IEEE Spectrum commemorating its one-year anniversary profiling the apparent mathematical inevitability of cascading power-system failures. That message raised a firestorm of protest from engineers who saw their can-do creed under attack.

Today, however, the black sheep who spotted the tell-tale signs of a chaotic self-organizing system in blackout databases have come in from the cold. The University of Wisconsin’s Ian Dobson, for example, says he is having success attracting grants — no mean feat for interdisciplinary research targeting the uber-unsexy field of power transmission. And the IEEE set up a task force on cascading failures (with Dobson at the table).

One obvious cause for rising consciousness is the fact that blackouts just keep happening — in Florida in 2008, in the Southwest in 2011, and around the world from Brazil to India and Italy. Another is that the tell-tale sign of a chaotic system that Dobson and his colleagues recognized in U.S. blackout data — a power-law distribution whereby large blackouts are over-represented — seems to be a universal pattern for power grids.

Even Dobson et al’s socio-economic explanation for recurring blackouts has stood the test of time. Dobson, former Oak Ridge National Lab chaos expert Benjamin Carreras, and University of Alaska physicist David Newman proposed that the power grid was a chaotic system driven by growing demand on the lines. Like a growing sand pile that crumbles when it reaches a critical state, they theorized that blackouts regularly reset the system. As I wrote in 2004:

Carreras, Dobson, and Newman wondered if power grids might approach the same kind of critical points as elements are added and power flows increase. They imagined that economic forces … seeking to minimize costs and maximize returns on investment … could push system operators to accept higher and higher power levels on their systems, setting the system up for a fall.

Read my 2004 article, The Unruly Power Grid, if you want to learn more. Modeling shows that this scheme does a good job of reproducing the pattern of blackouts observed on real grids, and the number and size of such validations is growing. Most recently Dobson and his colleagues validated their model using data from the Western Interconnect that links US, Mexican and Canadian transmission lines west of the Rockies.

A robust correlation between a model and observed data does not prove that Dobson et al’s mechanism is really at work, but it does affirm it as the best explanation on offer for the frequency of large blackouts. “Statistical patterns in the observed data match statistical patterns in our model, which is really as much as you can expect,” says Dobson.

What can power consumers expect? More blackouts.


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