Jamie's Blog

Ruby developer. CTO. Swimmer. Always trying to write more

so who’s afraid of the dark?

Well, I guess everyone knows by now about North America’s power problems. Rather than commenting further and generally repeating things someone else has already said, I’m going to pass on something useful.

Last October I attended the Emergent Engineering workshop at the MIT Centre for Bits and Atoms - a collection of talks ranging from product design to nanotech, biotech to … power supply.

David Chassin from Pacific Northwest National Laboratory described a catastrophic failure of the electricity supply in (I think) California which effected some 7.5million people over 9 hours. The powerpoint slides are quite dry and technical (flick to slide 11 and start from there). Basically, due to poor tree maintenance and the extreme heat a line sagged down onto a tree and caused a flashover. From there various pieces of equipment failed up the line, power was continuing to be imported from Canada and Utah, another line sagged and flashed over… you get the idea. There’s also nice QT video of a flashover at a transformer - impressive.

The conclusion (and the relevance to the workshop) was that small, isolated events can conspire to produce failures in large sections of the grid. The lesson is that the Grid cannot be managed as a deterministic system where events have localised and predictable causes and effects. Instead it is far more chaotic and needs to be treated as such. Imagine, if the Grid is like this now, how would it cope when every town, village, hamlet or ranch can produce power and contribute it back to the grid?

On a related subject, the latest issue of Wired contains a short description of how there will soon be a worldwide power sharing grid which will allow daylight countries to borrow excess capacity from other countries. There’s also a lengthier article (in IEEE Spectrum) on the problems with wind turbines feeding power onto the grid as they cannot produce a guaranteed/stable output. Oh, and I just noticed a paper from IEEE Computer Applications in Power which describes a Self-Healing approach to an electricity grid [pdf].

Right, that’s it. No more power talk for today.