Table 2.
Comparative analysis of construction costs between overhead transmission lines and underground tunnel transmission
| Construction Information | OHL AC | OHL DC | UGC AC | GIL |
|---|---|---|---|---|
| Rated voltage | 500 kV | ±600 kV | 420 kV | 1000 kV |
| Rated power | 2598MVA | 2400 MW | 7482MVA | 10,000MVA |
| Lifecycle | 30years | 30years |
XLPE cable: 30years Tunnel: 50years |
GIL: 50years Tunnel: 50years |
| Capital cost | 407,450$/km | 294,643$/km |
72,164,405$/km (Cable:42.5% Tunnel:57.5%) |
100,812,125$/km |
| Station type | AC substation | DC converter station | AC substation | GIL incoming station |
| Station cost (at both ends) | 333,949,072$ | 750,800,000$ | 436,226,676$ | 138,098,896$ |
| Operation cost(line) | 5% capital cost/year | 1% capital cost/year | 0.5% capital cost/year | 0.5% capital cost/year |
| Operation cost(station) | 2% construction cost/year | 1% construction cost/year | 2% construction cost/year | 1% construction cost/year |
| Energy loss | 6.70%/1000 km | 3.50%/1000 km | 11.91%/1000 km | 6.71%/1000 km |
| Ecological and landscape cost |
938,022 $/(year·km) (WTP) |
938,022 $/(year·km) (WTP) |
14,000 $/(year·km) |
17,000 $/(year·km) |
OHL overhead line, UGC underground cable, GIL gas-insulated line, AC alternating current, DC direct current, XLPE cross-linked polyethylene, WTP willingness to pay (applied to ecological and landscape cost valuation).