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The Forum > Article Comments > Paying twice, and more – why renewables are a luxury good > Comments

Paying twice, and more – why renewables are a luxury good : Comments

By Graham Young, published 21/9/2017

But renewables are in fact more expensive, and if you want to cure high prices, the last thing you would do is dose up on the problem.

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The luxury element with Mickey Mouse alternate power accrues to a fringe group of green fools, who use it to make them feel good & virtuous. That they gratify themselves at the cost of others, who can't afford the cost of their gratification is truly disgusting

There is certainly no virtue in self gratification at the cost to others.

It is a pity they don't go off & get enough education to be able to see through this scam. I am sure there are some among them, who would never promote this rubbish, if the understood the futility of their actions.
Posted by Hasbeen, Monday, 25 September 2017 10:04:30 PM
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Aidan,

1) An actual example from Hazelwood is selling power at $10/MWhr off-peak and $700 at peak. So not an exaggeration.

2) Baseload power is ideally suited for providing the vast majority of the power, as it can vary its load to cope with the low demand, ramp up in peak demand, and use gas generators for meeting the peak load. This used to give Aus the cheapest and most reliable power in the world.

3) The SA example was to give a comparison of the vast cost of power outages. However, the sensitive wind generators tripped when coal powered stations wouldn't have. See the AEMO report. SA also had a partial blackout completely caused by renewables.
Posted by Shadow Minister, Tuesday, 26 September 2017 3:49:11 PM
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Shadow,
1. It's an exaggeration to claim, as you did, that it OFTEN happens.

2. Technically that's load following rather than strictly baseload.
And what is the basis of the claim that it was the cheapest and most reliable in the world?

3. I'm well aware of the causes of the SA blackout. But you seem to be overlooking the fact that had the wind turbines not been set to shut down so abruptly, or if we'd had a bit of flywheel storage, or if the Heywood Interconnect had been set to maintain frequency at the expense of voltage, most of that cost would still have occurred because it was the result of the inability to quickly restore power (because the lines were down) rather than the fact there was a blackout.

And when did SA have a partial blackout completely caused by renewables?
Posted by Aidan, Thursday, 28 September 2017 2:03:53 AM
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Aidan,

Clearly, you have no concept of how the generation contract and bidding process occurs.

1) It happens every day. The bidding for power occurs in 10 minutes segments, the higher the demand the more of the higher priced bids will be accepted, and the higher the cost of power. In the dead of night when power demand is low, the large base load generators will charge very little say $10-20 /MWhr to keep their turbines spinning, but at 6 pm when demand is a peak, the peak demand charge is seldom below $400 /MWHr.

2) Again your understanding is epic, all generators can and do load follow all the time, Baseload generators can generate 24/7 at a minimum cost.

https://en.wikipedia.org/wiki/Base_load

3) Firstly, as you acknowledge, the line faults did not isolate the wind generators, but the faults did trigger them to trip out.

Secondly, generation protection settings are designed to protect the generators and not the network. That wind turbines with their electronics are less robust than 300MW generators is not a surprise. The Alinta and Pelican plant turbines that had been closed would not have tripped.

Thirdly, frequency collapse is caused by excess demand and the generators being unable to keep up. The only way that the Heywood interconnector could have helped would have been to supply more power. As the interconnector was already supplying more demand than it was designed for its protection tripped it to prevent damage to the interconnector.

"On 8 February 2017, over 90,000 households in Adelaide lost power for 45 minutes in the middle of a major heatwav
Posted by Shadow Minister, Friday, 29 September 2017 9:57:39 AM
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Shadow,
1) I'm well aware of how the generation and bidding process occurs. And I've often looked at http://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Data-dashboard#nem-dispatch-overview. I'm not denying it's normally cheaper in the small hours than at 6pm. But the huge fluctuations in price you referred to are the exception not the norm.

2. I checked that Wikipedia page, and followed the link on it to http://en.wikipedia.org/wiki/Load_following_power_plant
"Base load power plants operate at maximum output. They shut down or reduce power only to perform maintenance or repair."

3. I think you've let your imagination run away here. Are you seriously suggesting a thermal power plant would not have tripped if faults were detected in the line?

Regarding the Heywood interconnector, I accept what I wrote was a bit inaccurate. What I meant to say was that the SA network management should have been set to keep the frequency at a level the interconnector could cope with, even if that had to be at the expense of voltage until load shedding could be initiated.

4. The 8 February 2017 blackout certainly wasn't "completely caused by renewables". We had the gas turbine capacity at Pelican Point but it wasn't running.
Posted by Aidan, Friday, 29 September 2017 11:37:41 PM
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Aidan,

1 For starters, you have got the wholesale purchase price of power, which is averaged which smooths out most of the peaks and troughs. The peak and trough generation prices are far more variable.

http://www.nemweb.com.au/REPORTS/CURRENT/Dispatch_SCADA/

2 So you are a google expert only. Pity you couldn't read the whole article incl this chart which shows baseload thermal varying with demand.
https://upload.wikimedia.org/wikipedia/commons/f/f9/Baltwg.png

Coal-fired plants don't like dispatching load, but they are perfectly capable of doing so. Networks can't store energy, so even at 2 am, the generation has to match the load.

3 All generators have a certain "ride through" capacity to tolerate faults for a certain time without damage and the networks are built with redundancy and protection systems to trip out and isolate parts of the network that have faults quickly before the generation is threatened. In SA when the faults occurred the wind farms tripped out, but the thermal power stations did not, they only shut down when the network collapsed.

Aidan, I don't have enough space to point out all the laws of physics you would have to violate to do what you suggest, but basically:

Generators, power lines (Heywood interconnector) etc are limited by the current.
Over demand on generators for power slow them down (under-frequency)
Power = Voltage x current x power factor.
Now take a wild guess what happens to the current when the voltage drops?

4 Half of Pelican point like Alinta had been mothballed and had no gas available primarily because the variability of wind power had made it economically unfeasible. So yes renewables and their inability to provide peak power were the main cause.
Posted by Shadow Minister, Sunday, 1 October 2017 8:44:51 AM
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