California transmission line wildfires

Co-referenced with San Diego case above; Tom treats them as one teaching unit.

So copper has unique electrical and thermal conductivity, and even though it's much more expensive than aluminum and steel we use it. Now, aluminum has sixty percent of the conductivity of copper, and so all those big 345 kilovolt transmission towers — that's aluminum, because you don't want to pay that much for the copper. However, the aluminum tends to get soft. So you actually make a composite. Those are steel cores with aluminum on the outside, and the steel gives you the strength. One of the reasons they're so tall is that when everybody's running their air conditioners during the summer, the wires heat up, and they actually have to make them tall enough so that as they heat up and expand, they don't touch the ground. Because if they touch the ground, they will start a forest fire or a brush fire. Plus it's not very good for the circuit breakers back at the power station. You'd lose your power. Seven or eight years ago they had some tremendous wildfires in San Diego that burned down all that part of southern California.

1060 aluminum catenary lines (on steel core) sag in summer heat, contact trees, arc, ignite drought-dry vegetation. Utilities settle for hundreds of millions, recover via the rate base. Used to motivate the introduction of 1060 alloy and to illustrate why aluminum's low-temperature strength loss matters.

Worse, if you're having a drought in the area — so Southern California wildfires and others got started by the line striking the ground or striking a tree, arcing. You've got a drought, you're hitting a fir tree that hasn't had any water, it's a pretty interesting fireball. Starts a big forest fire. Some of the utilities in California have paid hundreds of millions of dollars in damages for starting these major fires that you read about in the paper. They've got a thousand firefighters fighting for three or four weeks, homes are being destroyed, and there have been some big settlements. Why do the utilities do this? Because they're going to get sued, and when they go in front of a jury they're going to lose, and they're going to lose even more, so they settle for hundreds of millions of dollars. But it's okay — they just put it right back into the rate base. So everybody in California is going to be paying for that. If you lost your home you want to get your money back, but most people don't realize that's why California has some of the highest rates. They've got attorneys, of course. You've heard the joke — why does California have so many attorneys and New Jersey has so many toxic waste dumps? New Jersey got first choice.