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Comment by ars | Hacker News Reader

Here is an example: https://www.reuters.com/article/us-california-wildfire/as-wi...

A branch broke and landed on a power line, sparking a fire.

I'm curious what PG&E could do different, it sounds like the tree wasn't even very close to the power line, but wind pushed it.

Turning off power like this during wind-storms might be the permanent new normal.

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Underground the power distribution like in France.

It’s expensive but probably less costly in the long run.

France does everything right (but it also does everything wrong.)

Wouldn't that cost something like $1 trillion to do for the entire state?

Math: 155147 miles * $750/foot

And an article https://www.desertsun.com/story/news/environment/2019/10/11/... confirming it's pretty much out of reach. $15,000 per household estimate (and 1,000 years!!).

Well then everyone has local solar with a powerwall for when PG&E shuts down. Maybe that's cheaper? Honestly I think PG&E could bury the lines cheaper than $750 a foot.

Maybe, but I think CEQA will pretty much guarantee that it will end up being a bit more expensive than even that.

You wouldn't necessarily have to do the entire state but rather start doing this in high-risk places first.

Good point. Is it also true that high risk places (forest/rural) are probably cheaper and easier to install underground than low risk places (urban)?

Not sure about that. The high risk places are also often in remote, rugged terrain. What you save by not having to disrupt other infrastructure you might end up spending just to get people and equipment to where they need to be. Interesting perspective here: https://www.wsj.com/graphics/california-wildfire-pge-drought...

A lot of long-distance, high-voltage transmission crosses what's effectively wilderness. You've got issues of unstable slopes, earthquake faults, flooding, and ground-current losses (a big problem with undergrounded power).

And that's before you look at getting crews in place.

Then there's the question of monitoring, servicing, and repair after undergrounding.

It's definitely an option. But not a cheap or universally applicable one.

Maybe ultra sparse settlements on a scale as today are unaffordable in the long run? It not just power but also the roads and communication links. Accounting for infrastructure maintenance is not done properly.

Well the obvious thing to do is to bury the ones in wind problem/fire risk areas

> $750/foot

2-3 times more than per square foot price of building a luxury house in California, that number totally checks out!

Underground power distribution doesn't last as long as above ground. So not only is it more expensive to install, you have to reinstall it more often, plus spend more money on repairs more often. Repairs take longer as well because you have to dig up the lines to do it.

The vast majority of power lines in France are overhead.

RTE overhead lines: 100000 km

RTE underground lines: 5400 km

https://www.rte-france.com/fr/document/statistiques-reseaux-...

If you are intending to distinguish between distribution and transmission, the lines in question in California are transmission lines, not distribution lines.

Not needed really. We have last mile underground, but major distribution lines are over air. However all plants higher than few inches are cut down under the lines the width of the cut depending on how high the cables are. I can imagine it wouldn't work that well in the mountains. Here it is just a matter of regularily mowing the whole thing (few times per year).

PG&E chose not to put lines under ground because they will likely break in case of an earthquake.

That sounds like and excuse. I'm Italian and back at home we also have heartquakes and wildfires problems. And yet a lot of our distribution lines are underground (apart from the high and ultra high voltage ones).

It's the high and ultra-high voltage lines taht are the problem here. A lot of in-town power lines are buried in California, but those aren't the lines that are under scrutiny here.

Assuming that’s the case, can anything be done to GVR above ground cables to make them less prone to arching / creating fires?

Earthquake-induced ground movements tend to be in limited areas immediately adjacent to faults, unless the effects are cause by induced land movements (e.g., landslides) elsewhere.

An above-ground fault-crossing, with slace sufficient for maximum predicted ground movements (generally on the order of 5m or less) should generally address that.

Don't above ground lines break in the event of an earthquake?

It's pretty simple, you have to maintain the right-of-ways along your transmission lines. This is really basic stuff, it's astounding that it could be this mismanaged.

How about planned deforestation in areas of risk?

The problem is people often build homes far deep into these forests so actually deforesting the area would actually result in a massive amount of trees being cut down. Look at paradise, CA as an example.

And even with the current state of affairs, you can certainly find complaints already about PG&E "clearcutting" around their power lines.

That seems like a different problem though I can’t imagine there are so many people in California living in remote forests. I think the idea of cutting trees is a big no no regardless of whether it’s for net positive for environment or people.

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