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OT: Moorabal/Lal Lal wind farm 19-May-2009 At 5:43:01 PM lacto

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On 19/05/2009 TonyB wrote:
>
>Coal fired power stations are designed to be big enough to cope with peak
>power loads. Costs of electricity are more strongly related to the capital
>and manpower required to build and run power stations, rather than the
>cost of the coal.
>
>Windmills (and solar power) are unable to provide reliable power at peak
>load times. They cannot reduce the required number of coal fired power
>stations.
>
>Wind power ( and solar power ) are much more costly than coal power, even
>ignoring peak load considerations.
>
Coal power stations generally are poorly equiped to cater for greatly varying loads . When I was at uni we were quoted that brown coal would take 48 hrs to go from totally stopped to full power and their ability to quickly vary load is poor . And all those la trobe valley stations were either built or being built then . Those stations use coal to heat steam to run stem turbine generators and whilst they are extremely efficient users of the steam cycle the steam cycle can at maximum use around 30 % of the energy produced by burning the coal , the rest is put out into the atmosphere as heat or in hot watyer that disapated the heat back into the atmosphere through cooling towers and pondages. Gas turbines provide rapid response power and there is large capacity of this installed and up to 2000 Mw capacity being built or planned .Hydro also provides quick response but limited water are currently limiting its capacity. As far as I can work out the Victorian power companies pay little for the brown coal they use . Yallourn 1480 Mw was lost to victoria when the open cut flooded and most of victorias coal is reliant on three mines with little ability to supply other than their own power station.
IF you want proof of the inability of coal fired power to provide quick responses to load look at the spot prices of power during a 24 hr period ( varies from $5 to $ 10 to $70 on normal days and peaks on extreme use days at $3000 per Mwh. Ther are no proposed coal power stations in Victoria though there is coal gasifacation plants but not thermal (steam)
to burn coal at 30 % efficiency in La Trobe valley then send it at times over 600 km with transmission losses upto 20 % is not wise enegy policy.
Wind and solar both may not produce constant power but current (Hydro) and other technologies can economically store power for use when required .