Aug 27, 2008

It's the Network, Stupid

It is amazing how many of our current problems come down to the realization that it's the network, the connectivity, that matters. In most situations we know how to fix and enhance the nodes in the network. The links, and their patterns and structure, are the hard problem.

We are making progress in alternative energy production, but we still fail at energy distribution. Windmills and solar energy collectors have made great progress -- we just can't get the energy from where the wind blows and the sun shines to where the great population centers are. To do that requires a well-designed power distribution grid. Many critics of the current grid describe it as "third world" in design, quality and capability. Today's New York Times describes the distribution problem well.

Above is a network map of a portion of the US electric grid [drawn not to reveal geography]. Life is great if you live in one of the densely connected clusters using electricity generated nearby. Things start to get real complicated if energy needs to transferred from one cluster to another cluster in grid.

Distance destroys. Electricity does not flow like information or water or oil. It is not easy to direct, and much electricity is lost to heat when transferred over long distances. On the internet, 100 packets sent from Cleveland all arrive in New York wholly intact -- not so with a 100 MW of electricity generated in Cleveland and sold to NY. Even more electricity would be lost going to Miami, and forget about LA. It makes no sense to transfer electricity made in Cleveland to Los Angeles -- most of it would be lost during the trip.

Not only does physics get in the way, so do local interests. Then you have another power problem -- that of political power. Doing a social network analysis of the electric grid quickly points out key nodes and links that are highly between transfer points on the grid. They become gatekeepers/bottlenecks and either extract a toll for the transfer, or refuse transfer and require the buyer and seller to find a longer route to get from point of generation to point of consumption. And remember -- distance destroys.

Energy independence will take a lot more than just new technology at the point of generation. It will take the design of a much smarter network of distribution.


  1. In fact, if you build HVDC lines then you can do cross-country transfers with relatively small losses, certainly as good as is needed.

    Further, you could rearrange grid ownership to be more rational.

    There's little fixed in stone about the current problems with the grid. Decentralisation may be desireable for other reasons, but I think you're overplaying your network analysis here.

  2. Valdis - the interdependencies in the electric grid run deeper than the wires. No utility company can afford to keep on standby enough crews to restore service over its entire area after a big enough storm, and they all rely on exchange relationships to get crews in from neighboring utilities. (similar to fire departments).

    If/when the footprint of the storm is way bigger than normal, e.g. what I'd expect this one two punch of Gustav and Hannah, then the network of grid repair will be stretched.

  3. Ed's comment is on point... in the aftermath of Charlie, Florida received utility reconstruction crews from all over the southeast to help rebuild.

    This was a nice overview of the issue. The "link cost" in the network - is measured in distance via the cost to lay, build and maintain fiber but also in the inverse-square distance losses which are not usually so severe in the networks we model.

  4. a followup -

    One of the issues in the reconstruction of the energy grid around New Orleans and Baton Rouge hit by Gustav is that the storm damage hit transmission lines hard enoug that NO and BR became essentially a "power island" within the Entergy region.

    Reconnecting islands in the power grid to the main grid is really hard and tricky, not just a matter of energizing lines but of balancing things "just so" so that you avoid wider grid failures.

  5. Valdis, how badly affected were you by the Ike windstorms in Ohio? It was as if that entire state's power infrastructure was designed to blow down at winds of 51 mph.