Is it time to seriously consider burying power lines? 2

[Mbrooke]

I'm starting to get the epiphany that it is no longer cost practical to keep power lines above ground. Case in point- storm rolled through the North East during the night. Eversource Connecticut alone had 85,000+ without power and currently about 61,000. 26,000 for Central Hudson and Gas. 10s of thousands in National Grid territory. School buses driving over power lines, people trapped in homes, outages expected to last 3 days.

https://outagemap.eversource.com/external/default.html

https://outagemap.ny.nationalgridus.com/

https://outagemap.ma.nationalgridus.com/

https://stormcentral.cenhud.com/

Even Con Ed has them in their over head network but not to the extent its neighbors do:

https://apps.coned.com/stormcenter/external/default.html

Oh, the school kids:

https://www.wfsb.com/news/school-bu...cle_3b973ac4-fc9b-11e9-97bb-47a18a7356d4.html

Normally I wouldn't blink. But this is now happening every month it seems. Just two weeks ago the same thing happened across the north east. Prior to that micro bursts. Every winter an ice storm. Random Tornadoes. When I was younger it was just a few thousand customers and few hours until power restored. Now its 100,000 and close to a week without power.

Then look at PG&E. Texas. Middle America. I keep seeing a trend where distribution infrastructure is destroyed on a multi state level in just a few hours.

There is also the safety aspect of people driving over live wires, becoming tangled in them, people handling them during storm cleanup (no one takes the warnings seriously around here), attacking line crews and even folks taking the copper primary for scrap because people (and even police) assume them to be line workers in their T-shirts and white pickup trucks. Stores throwing out tens of thousands in food. Lost business. Fights at the gas pump. CO poisonings are another biggy- to this day people still think running a generator in doors with a window cracked is perfectly safe.

 

[DM61850]

It would be very expensive. It cost about 6 times more to bury transmission and distribution. That is a lot of money that could be spent on other items which would add more reliability to the system. I don't think there is a good business case to bury everything other than it looks better in expensive neighborhoods, there is no space to put it above, or you are in a coastal region that gets hit by hurricanes a lot. With it costing 6 time more, you could build a ridiculous amount of redundancy into your network and still spend less money.

When you see these all these people losing power, I think that one thing that needs to be kept in mind is the long-term availability of the customer. I strongly suspect that these customers have had very reliable service and to plan the design of a system around a catastrophe would be too expensive. In Houston, if you really want 100% instead of 99.99% availability, buy a generator.

 

[Mbrooke]

Had very reliable service. When 100 years storms are the monthly norm, there gets to point where service continuity takes precedence I think.

 

[dpc]

For distribution circuits the cost differential is probably 8 to 10 times. For transmission voltages, it's even greater and the cable insulation will fail eventually. What's the actual data on reliability of OH vs UG circuits? UG faults take much longer to find and repair. I don't know the answer, but simply saying we have to bury all of the power lines seems, well - simplistic. In the west there are tens of thousands of miles of OH lines. I think improvements to harden the existing OH lines would be a more realistic option in many cases. How are SMUD and LADWP doing versus PG&E? (I don't honestly know.) Generalizing a solution based on the performance of one of the worst utilities in the US may lead to bad decisions. PG&E sold the governor a pig in a pole revolving around "renewable" energy and distributed generation. Now CA is paying the price.

 

[itsmoked]

PG&E.

Miles of power lines in PG&E area: One hundred and six thousand miles

Average price to bury power lines: 3 million dollars a mile

Number of customers: 16 million

Cost per customer: $18,750/customer.

Estimated time to completion as demonstrated currently under urgent directed bury orders: Approximately 17,000 years.

It's not a viable option!

Using tree-wire in logical places, burying it in very specific locations, and actually doing some inspection and maintenance is what's required.

Both the Kinkade Fire (~80,000) Acres and the Paradise Fire (153,000) Acres were caused by worn-out transmission line mechanical equipment. SIMPLE equipment! in the Kincade case a simple steel ring that finally wore out after decades.


Presently talk has come to: A private for profit company operating as a monopoly can not be expected to plow money back into maintenance and upgrades as the primary focus is on stock prices and dividends. Big monopoly utilities should be either non-profit or government owned.


Keith Cress
kcress -

http://www.flaminsystems.com

 

[davidbeach]

The median repair time following and overhead conductor fault is measured in seconds. Air is both inexpensive and self healing. A reclose or two takes care of lots of problems. Underground there’s nothing to be gained by reclosing.

 

[Mbrooke]

@itsmoked: 3 million seems high for 15kv. I mean Con Ed does it. Europe does. Most 1st world countries are doing it. Why not the US?

 

[Mbrooke]

@David: Yes, but imagine a permanent fault. In cases where its once every 5 years on an overhead line it is a no brainier- acceptable for the cost. Now imagine every 2 weeks to a month- across 2% of the entire system. It gets pricey.

Granted underground fault take longer to fix and find, but auto loops or even a network setup can help.

 

[davidbeach]

In dense urban areas $3M per mile may be an easy decision. But in remote area where that pays for the connection of five customers who generate less than $10k total per year who pays?

 

[Mbrooke]

The urban and high demand customers. This allows more rural customers to be hooked up, and considering the longevity of equipment the hope is the rural sector will pay it back.

 

[3DDave]

Sure. Just like urban and high demand customers are forced to pay for fiber Internet to rural areas. Except that no one is running fiber to rural customers. Because any rate increase will go to profits and lobbyists prevent it from going anywhere else. Urban customers will pay buried power back in a year or two. Rural ones will pay it back in a century, if ever. Guess what investors are interested in.

 

[itsmoked]

True dat Dave!

MB; $3M/mile is PG&E's estimate and I can't speak to it very well. I suspect an Urban Mile might be 15~20M$/mile and some rural might be $1M/mile. It probably depends on how many hook-ups and how many competing underground interferences are involved.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Mbrooke]

1 million sounds more reasonable to me. I think 3 million is somewhat inflated IMHO. It also depends if you are XLPE through conduit and manholes or doing a direct bury.

 

[dpc]

Cost/mile depends on the voltage and many other factors. Clearly UG is vastly more costly than OH in most circumstances in terms of initial costs. According to news reports, at least one fire started near a line where the 15 kV underbuild was de-energized, but not the transmission line on top. If PG&E can't keep up with maintenance and trimming on OH lines, UG transmission lines would be an even greater problem.

 

[Mbrooke]

I'll give you that- but also remember the north east utilities having to rebuild overhead lines every month. I think an investment scheme is needed where someone can convince banks and investors to lend money to utilities solely for undergrounding on the basis of sustained economic factors and long term savings in mitigating outage restoration costs.


I'll ask this: why has Europe managed to underground so much?

 

[3DDave]

If, in the face of high costs, an economic area proceeds with some action, there are two things which come to mind. The first is that there is some other factor, such as aesthetics, driving that decision. People pay millions for smears of color on canvas; perhaps they value a view that doesn't have wires in it. The other is that the extra money is worth making extra bribes. Near me some politicians were pushing to have overhead connections to poles changed to underground - from pole to house would be buried. Why? Guess who pays for it and who gets paid to do it. Plenty of motive to force a funds transfer to someone who bribed you. But not enough to dodge the obvious accusations and eventually the politicians retreated.

 

[Mbrooke]

Well, at the same time one could view it so the line workers will always have a job and companies selling overhead hardware will always have income.

I know its hard to imagine this being the case now- but if you ask me one in 100 year storms will be so frequent above ground will start to look impractical.

 

[dpc]

Most of Europe has a much higher population density and this drives the need/desire for UG distribution. The western US just isn't comparable in terms of geography, geology, and population density. Many REAs in the west still use Copperweld for OH distribution lines due to low population density - one or two customers per mile. If it wasn't for the REA, many areas would still not have electricity, IMO.

 

[3DDave]

The economics are different. Employing a small number of line workers for a long time and selling a small amount of repair parts for a long time doesn't generate the short term huge cash flow that very expensive projects do. It's exactly why, in the USA, there are companies that build giant subdivisions and use that potential cash flow to bribe people into changing land use regulations vs no one doing the same for the minor repairs of all the homes that already exist. The density of the funding is too low for continuous minor repair to generate a well funded lobby. Likewise the 50 to 70 year old US interstate system should have been peeled up and repoured, instead it gets pot-holes filled with garbage materials while politicians sign off on expansion projects to those subdivisions. Much harder to lobby on a $200 pothole patch than a #30 million dollar highway extension.

No one in politics cares at all about keeping line workers employed, at least not in private where the deals are made.

 

[Mbrooke]

Copperweld?