TacTurtle t1_ixe7g73 wrote
Reply to comment by danielv123 in HVDC macrogrid would reduce climate pollutants and electricity costs while transmitting low-cost renewable power by manual_tranny
2200mcm high voltage cable is running closer to $11-15 per foot, uninstalled. You are talking triple or quadruple that for underground rated cable
Each phase would running multiple cables, so $11 x 5 x say 6 runs per phase x 3 phases = $990-1350 per for cable alone, uninstalled without external conduit.
Citation:
Trenching and laying pipe or cable subsurface is $800-1000 per foot in existing public right of way without additional permitting cost or fill.
Add in 360 degree thermographic inspection, that’s probably another $10-20 /foot.
Then for buried HV cable you need like a 200 foot corridor for safety, so that is like $1000-2000 per foot even at a modest $25,000 / acre
danielv123 t1_ixe7xu4 wrote
And thats thin for distribution. That is close to the minimum diameter of the cables we are planning to make for offshore windmills.
TacTurtle t1_ixe9unn wrote
Yeah at that point you end up running multiple cables per phase so the linemen can still actually physically bend and move the cable - at least on the distribution side.
Who even makes HV underground cable rated for DC? Okonite’s catalog only has underground rated to like 35kV, versus 69kV for above ground.
danielv123 t1_ixel5tr wrote
Prysmian group makes up to 1100kv AC underground apparently. Nexans has delivered 500kv underground systems in the past, don't know how high they go. For these projects the cables are always custom made though, so there isn't really a catalog to pick from.
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