Shadow,

1. AIUI the prices shown at http://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Data-dashboard#nem-dispatch-overview are the spot prices, NOT the average prices. If you click on the PRICE AND DEMAND tab, you'll see the quoted prices are the five minute spot prices for each state. I am of course aware that a lot of electricity is forward sold, and of course the price for that is much less volatile than the spot price.

I don't know what you thought the significance of the link you supplied was - it appears not to show prices.

2. I accept that most (though not all) baseload generators give some ability to vary output, though they're not good at it. They're certainly not ideally suited for providing the vast majority of power, precisely because they're crap at ramping up.

3. The wind farms were connected directly to the powerlines that were hit by tornadoes. The thermal power stations were not. So of course it was the wind farms that tripped first.

Though the continuous rating of generators and powerlines is limited by the current, a slight drop in voltage for a few seconds shouldn't affect how much power a generator can output.

AIUI (from reading the Advertiser online around the turn of the millennium) when SA's power was at its most unreliable and there were no wind turbines, they did let the voltage drop when there was a shortage of power. Following complaints that this was damaging equipment, they switched to a policy of rolling blackouts instead. So there is a precedent for letting the voltage drop to keep the frequency up, and I'm suggesting that we can do it again if the frequency ever drops too much for the interconnector to cope. Never ever for more than the few seconds it takes to implement load shedding, though. And flywheel storage should also be considered to stabilise the frequency.

(tbc)

Shadow (continued)

4. The mothballing of Pelican Point had more to do with competition from the old coal fired power stations than from wind power. And there was plenty of gas in the pipeline, but we had the ludicrous situation where the power station had to find someone to sell them the gas before they started using it, resulting in inability to make power available when needed. A use now buy afterwards policy would be far more sensible, though you may find it counterintuitive.

Aidan,

1) The power generators don't bid all their power at one price, their bids are layered with a large portion of their generation being contracted. The bids are based on chunks of power increasing in bid price so that as the price increases so does their output. I am talking about the peak price, the variation in the wholesale spot sales price will be considerably less.

2) All baseload generators can vary their load even nuclear power stations, they might be slower than small gas generators and doing so is not profitable, but they can and do.

3) The powerlines that faulted were not the only power lines connected to the wind farms. The AEMO report clearly indicated that the oversensitivity of the wind generators protection systems was a major contributing factor to the blackout.

Decent networks have several layers of redundancy and should be able to cope with several failures simultaneously. With the loss of the coal-fired plants, this redundancy was whittled down to dangerous levels.

Network frequency drops when power demand is higher than supply, the way to stop the decline is either by shedding load, or increasing supply. As for dropping the voltage, most consumers can ride through a 10% 20% voltage drop for a short time but will not reduce their power consumption by much. Voltage drops by more than this will start to damage consumers equipment. Heywood tripped because the power required to maintain the network frequency was too high, once Heywood had tripped, it was all over.

4) If your logic was correct, Pelican Point would have started up its second half of plant when Northern power station closed.

The experience in Germany is that as wind and solar came on line it was the gas generators that closed and not the coal-fired plants.