My good friend is an engineer whose job has been to work on transmission line construction projects for several utilities including our local one. He just finished testifying at a court case because the utility was being sued by a group of homeowners for running the lines above ground rather than burying them.

His testimony was based around the fact that on average the cost to bury lines is roughly 10x more expensive than running them above ground, and he has had this experience across multiple different projects.

So when people say "it's expensive" they are literally referring to a factor of 10x cost increase. Maybe it's worth it in some cases compared to the costs of power outages and fires, but understand that we're not talking about a "slight increase" here, and that the people making these decisions are generally highly trained and experienced subject matter experts who are already doing cost/benefit analyses to take the best course of action that they can.

I suppose the only other variable we’d need would be what is the initial infrastructure cost as a share of the total lifetime operating cost of a distribution system. Including things like maintenance and starting wildfires. There may be a break even point where 10x cost is a sound investment.

Is the cost related to the rarity of buried power lines?

Consider doctor testimony that used to be given for deaths while under anesthesia. "It's normal" and "it just happens." Luckily juries didn't listen and anesthesiologists were forced to reconsider their daily practice.

It sounds like you are asking "is there an economy of scale?" to burying power lines. Or "is there a learning curve that will drive the costs down?", like for solar.

The answer seems to be 'no'. Digging and burying pipes is something we've been doing on a massive scale for hundreds of years and there's no reason to believe more volume will improve the economics. It's probably getting worse since new development means more roads to dig up and more structures to plan around.

There’s a big difference between burying distribution lines and transmission lines. It’s transmission lines that have caused the most destructive fires in California and those are indeed too expensive to bury.

Does anyone know if transmission lines can be buried? Some high voltage DC can be in the hundreds of kV, is there a limit to what can be buried in moist ground even remotely efficiently? You’d need a good amount of electrical insulation, but also thermal conductivity (I assume these lines heat up?). Any experts here?

Absolutely they can be buried. They must be insulated, but that's not particularly expensive. There are thermal limits, as you mentioned, but that simply requires appropriate engineering.

It costs $1 million per mile (roughly) to bury transmission lines. PG&E has about 18,000 miles of transmission lines. That's about $18 billion to bury the lines. Sounds like a lot, but...

...the estimate price of these multi-day blackouts is on the order of $1 billion per blackout. Given multiple blackouts per year, and we're talking just a few years to pay back the price of burying the transmission lines. https://www.sfchronicle.com/business/article/A-cool-billion-...

> the estimate price of these multi-day blackouts is on the order of $1 billion per blackout

But that's not the cost to PG&E. PG&E (or the state) would have to find a way to get some of that somewhat hidden opportunity cost.

The state already does that through regular, economy-wide taxes. (Maybe this is why it's a bad idea to grant a monopoly to a for-profit company like PG&E that doesn't take into account the externalities of power outages... Then again, Texas' very deregulated but non-monopoly ERCOT seems to do pretty well. So either state-owned OR deregulated may be optimums compared to PG&E...)

$1m/mile is off by like a factor if 10. PG&E thinks it costs $3-5m/mile to bury _distribution_ lines: http://www.pgecurrents.com/2017/10/31/facts-about-undergroun...

Good argument for burying PG&E, then, and starting over.

It is physically impossible to have long distance underground high voltage AC transmission lines due to capacitance: http://www.puc.nh.gov/2008IceStorm/ST&E%20Presentations/NEI%... HVDC wouldn't have that issue, but there's not much experience with HVDC in North America.

The issue is more with burying AC as I'm aware, the ground takes energy out by interacting with the magnetic field. With DC there is only a static field and less parasitic loss and you can add enough insulation. There shouldn't be appreciable heat generation in either.

Consider the fact that we lay oceanic cables.

CA appears to require lots of power lines because of sprawling development patterns, electricity generation located away from population centers, and a significant proportion of electricity imported from other states which must then be distributed intrastate.

It appears that CA power line vegetation management is woefully lacking. Given the fire risks, the right of way for high tension power lines should be essentially bare of vegetation.

PG&E is less than one-third done with its 2019 tree-trimming work

https://www.sfchronicle.com/business/article/PG-E-is-less-th...

I suppose once could burry main lines, and have a mechanism that can remotely disable parts of overground lines, and enable them once the fire risk is over. But either way, not acting in anyway makes the US/CA look like a poor country - they certainly have all sorts of excuses for power-cuts in there, and why it is impossibly expensive to fix.

Could also upgrade some infrastructure in the process, like running fiber. Might not be free but worthwhile.

There you go. Seriously sad to read about how this happens in one of the most tech developed areas of the world.

And perhaps even begin building a superconducting grid ad for once in PG&E's history, doing something that was pro-active rather than reactive.

Is there a superconducting grid anywhere on a large scale? Last time I read up on it, the experiments by Detroit Edison were a failure due to an inability to keep the coolant from escaping because it used liquid helium. This was probably a decade ago. Have there been advances since then?

Large scale, no, but succesful in New York to bridge two power grids.

https://hardware.slashdot.org/story/08/07/12/0135227/superco...

We don't have the technology for a superconducting grid. It also doesn't really make sense, as grid losses are not that big. On very long connections we might want to switch to HVDC, but keeping superconductors cool would most likely require more energy than you save.

Controlled burns are also important, and California has been neglecting those lately too.

They won't need any for a while after this.

All the money is being spent to extinguish the fires and not to prevent them from happening in the first place. Brush clearing and controlled burns are a must.

In my country the burying has already been done in dense areas decades ago and is progressing in the countryside.

Granted, it's about the least earthquake prone area in the world. Also differences in grid architecture between USA and Europe might make burying more expensive in USA. https://electrical-engineering-portal.com/north-american-ver...

People should be allowed to purchase the services they want and not purchase the ones they don't. So maybe some people prefer infrequent power outages at a cheap rate to reliable but expensive power.

It's not like there aren't other solutions; generators, batteries etc.

FFS with the pressing need to decarbonize energy you're upset about people not being able to handle a few days a year of intermittent power?

Burying the power lines underground does make sense to me, but I live in a quiet inland forest in an area that hasn't seen large earthquakes in recorded history, and I don't know anything about the area affected in this particular case.

Could it be that they anticipate that future earth quakes could cause such devastation that repairs to underground cables would be too difficult/time consuming?

Is there literally no solution that exists between burying power lines and keeping the lines completely exposed that would be cost effective and improve fire safety by some factor? I imagine insulators in high risk areas might do the trick but I am no high voltage expert.

Yes, these kind of insulators are called "the ground" ;)

I personally wonder why they don't go with accessible infastructure tunnels like old city sewer systems instead of having to dig up roads for wires and pipes. The two obvious "why nots" I can see are the initial expense of such tunnels and rodents or other pests damaging it.

well there's a couple things, vague meme strawmanning isn't very constructive, and the reality is that the relevant people who have been saying stuff is too expensive is California.

This stuff goes back to Enron and even further. The liabilities utilities are exposed to in California don't match the rates people are paying, and the electricity rates are already really high. You can claw back all the profits, all the bonuses you want, the money you're talking for proper maintenance is way higher than that, the money for a complete overhaul is higher than that.

You can make the utility public, but then you have to contend with the fact that CPUC has been there every step of the way.