reineraggie09 said:
schmellba99 said:
Gunny456 said:
I have never understood why America insists on running all power lines in the air. Many European countries bury all transmission lines.
The excuse is " it's too expensive". But yet when hurricanes and tornadoes wipe them out there is always plenty of money to rebuild….. from taxpayers and rate hikes.
We can bury gas pipelines but not electrical lines. Seems it would prevent weather related power outages and be a lot more secure from military threats…. to say nothing of the aesthetics of not having all that crud sticking up in the air.
The larger kva you get, the more per lf increase in price.
It would cost around 10x-15x per linear foot to run 354kva underground versus overhead.
345kva runs ~ $1.5mm to $2.5mm per mile to run overhead. That same line would be in the general ballpark of $25mm per mile if you buried it. Take a 100 mile run - overhead it would be ~$250mm to construct whereas if you buried it that same cost would be ~$2.5 Billion. That is a significant difference in cost, and one that most utility providers simply cannot afford without having rates jump from $.15/kwh to $1.50/kwh or more. I doubt you or anybody would be all on board with their electric bill going from $200 per month to $2,000 per month.
Smaller lines can, and often are, run underground because it is far more cost effective in the short and long run to do. But you can't apply the same logic to everything because it doesn't work unfortunately.
I'll step in it and have the opportunity to look dumb. I don't understand why it's 10x more expensive in sparsely populated areas. I understand cities with navigating structures but not rural areas. The transmission line should be the same. (1) You don't have the cost of the materials and labor with the poles (those can't be cheap). (2)Instead you have the cost of the underground conduit. I would bet one pole would buy a decent amount of linear feet of conduit. (3)Additionally, the labor should be comparable with the added cost of needing to do stuff in the air vs standing in the ground. Maybe some added cost in trenching. But I can't believe it actually costs 10x.
I'm not saying it isn't charged 10x just that it shouldn't cost that much. I'll shut up and take my medicine for my ignorance now.
1. The poles and/or the structural steel transmission towers aren't that expensive in the grand scheme of things to fabricate and construct. They are made from standard W, L, C and tube shapes that are readily available, easy to assemble and designs generally are already done. They can be fabricated and erected in a fairly short amount of time. Poles can be set even faster.
2. UG conduit - especially for a large load line like a 345kva or whatever, would be substantially large. Most of the time you are looking at 8" diameter HDPE. And it isn't just one conduit - you need ~8 conduits for a single circuit. Plus the access manholes, which would be large. Plus the excavaton costs, backfill costs, concrete encasement costs at various areas where protection would be paramount, plus the cost to weld the conduits since 8" HDPE would be in 40' joints. That would be 132 welds x 8, so 1056 welds per mile of transmission line (assuming no additional bends, fittings or surprises along the way), plus any tunnelling or boring that would be required, etc, etc, etc. Simply put - all of these things add up in costs to about 10x-15x per mile more expensive than running overhead. Oh, and the wire isn't the same wire either - UG wire is singificantly more expensive than overhead wire because it has to have better jacketing (some overhead wire doesn't have any jacketing at all). More costs on to of more costs.
3. Underground construction is significantly more expensive - in any industry - than above ground for a host of reasons. If it were a 1:1 exchange we'd have everything in the world underground. But it isn't - subsurface work has always been and at least for your and my lifetimes always will be more expensive because of the nature of the beast. It isn't as easy as just digging a hole or digging a trench and throwing stuff in the ground.
