15 Comments
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Kilovar 1959's avatar

There are distance limits to underground AC Transmission, the higher the voltage, the shorter the distance. That's why undersea cables are all DC

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Gene Nelson, Ph.D.'s avatar

Excellent example of misplaced priorities. Chino Hills does not have wildfire-prone forests like the area surrounding Paradise, California.. Based on my experience as a CPUC intervenor, I believe the CPUC is extremely corrupt.

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Scott McKie's avatar

To the person who wrote the question - how about doing some homework first before posting such a question that has such an obvious answer.

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Michael Magoon's avatar

Or just ask AI.

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Scott McKie's avatar

Hi Michael - I don't use AI because I don't know who programmed it. In this case though - the inferences were so off the wall that I couldn't pass it up.

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Stanley Vick's avatar

Most people believe that electricity comes from inside the walls. Try explaining any of this to them and their eyes glaze over.

Wonderful article, though.

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American Psycho's avatar

To quote Metallica, “sad, but true.”

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Barry Butterfield's avatar

an excellent summary, folks. thank you. like everything, it is a matter of risk evaluation. i think costs of burying low voltage T&D is coming down with the widespread use of horizontal directional drilling.

something else to consider when evaluating costs in an older, "developed" neighborhood is the cramped and already crowded right-of-way.

it saddens me greatly when I see folks willing to give away money for otherwise useless generating systems (unicorn farts and fairy dust) while neglecting federal interventions for grid strengthening.

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American Psycho's avatar

An eye-opening explanation, Leap. I thoroughly enjoyed the article.

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Lee's avatar

Totally agree. And the last 400 feet can be the most expensive and troublesome.

For a cost example it costs about $2 million a mile to build overhead hi voltage - 220kV and above. Higher voltage can be a little more expensive...higher towers etc.

Several years ago Southern California Edison was forced to bury 8 miles of 500kV transmission line through the city of Chino hills. A high profile democrat had moved to a new district and needed votes. Somehow he got the CPUC to mandate the under grounding. This was the first time anyone had tried to do this. The 8 miles cost SCE's ratepayers $4 billion. $500,000,000 per mile. Don't expect to see underground transmission any time soon.

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Lam Macro Research's avatar

Pole smokers

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Scott McKie's avatar

I totally agree.

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dave walker's avatar

Trade offs are the solutions in nearly all cases. Excellent piece.

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B Apple's avatar
2dEdited

Great summary, one of the best I’ve read.

From my experience, you’d also have to consider the cost of upsizing your conductors or running multiple parallel conductors to derate for underground. At the medium voltage level that considerably increases costs with the extra copper/aluminum needed. You go from a conductor wide open in air to one completely encased inside conduit (likely in a concrete duct bank). That conductor will start cooking much faster without the air flow to cool it off.

I also make the argument all the time to the average layperson on how overhead lines make fault diagnosis very quick. I live in Louisiana and was able to find the exact location of the line fault in my neighborhood after hurricane Ida came through. If that had been underground, it would have required more equipment and excavation.

I also hadn’t considered the ability to service live conductors with the bucket trucks being isolated from ground. Thank you for mentioning that. In my world it’s almost always lock-out tag-out.

Overhead lines may not be pretty and have their issues but most don’t realize the scale and cost to bury them. You did a good job putting it succinctly.

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BRIAN CAM's avatar

Just Bury IT? That why I like GAS Pipelines to move Energy, DIG SAFE needed sight unseen.

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