power lines, page-11

A most interesting lateral thinking debate happening here. Are people familiar with the Tasmanian Bass Link project? This is somewhat similar to the Norwegian dams situation. Tasmania provides NEM with peak power via the dc Bass cable at high peak prices from its hydro generation network. The Tasmanian highlands are littered with enhanced storage lakes and dams. At off-peak times power returns to Tas where the water is pumped back up to the higher level storages. The whole system operates like a continuous giant surging mechanical capacitor (analogous to an electronic capacitor) on a daily basis.

The difference between peak and off-peak prices generates very significant revenues. It also mean coal fired generators on the mainland can be kept going at more regular paces (at night, etc). Even if the Otway Basin hot rocks get developed it will be some time before Victoria's coal fired plants become redundant. Since geothermal generators can have a reasonably short start up time the price of peak power should come down over time.

Your reference, Peter, on ac/dc transmission is most interesting. The building of colossal transmission line towers is hideously expensive. A dc line at the same high voltage could be at a much lower height although more support points would be needed. A friend of mine travelling in New Zealand commented on the dc line on South Is (eventually ending up in Wellington), as being amazingly low but looking 'very thick'. Besides reducing line losses the tower savings could be considerable. Your cost estimate of $1M/km for 275kV appears very reasonable based on several examples. Would need to add more cables as generating capacity at Cooper Basin ramps up.

sf120. Your reference and cost was modelled on a 33kV line.

Juke