Choke Point Briefing – Intermittent energy must have 100% backup from conventional power

Cover sheet 

Purpose: To promote awareness of the choke point problem with intermittent (wind and solar) energy and the danger that this creates in the unprecedented situation at present where we have no spare capacity of conventional energy due to the close of several coal fired power stations in recent years. .

The Critical Issues:

(1) After the loss of several coal fired power stations, most recently Hazelwood, we have an unprecedented situation with virtually no spare baseload capacity. We are “running on the rims”with no spare in the boot.

(2) Many times a year when the wind supply is critically low the system will “choke” unless  conventional power sources (dominated by coal) can provide 100% of the demand for electricity.

(3) That situation is very rare at present but it will be a constant danger when Liddell closes in 2023 taking almost 2GW of baseload supply out of the system.

Background. It is generally assumed that the wind and solar projects under construction  will steadily make  the coal-fired power stations redundant.

This narrative is destroyed by the “choke points” that occur when the supply from solar and wind is at the lowest points and the demand for power peaks in the evening.

Key features of the situation. (see Briefing Paper attached)


That all politicians be advised of the critical threat posed by the choke points.

That pundits on TV, radio and print media be advised and provided with supporting information so they can pass the message to the public.

That news and weather reports include the % of demand for power being supplied by wind at the time.

Choke Point Briefing Paper

Purpose. To provide supporting information and speech dot points to explain the choke point problem.

Key features of the situation.

With the loss of several coal fired power stations in recent years there is no spare capacity in the system. This has been signaled by the AEMO and it has prompted the use of the emergency system for back-up supplies called the Reliability and Emergency Reserve Trader process. [This just means taking power from high volume users to minimise rolling blackouts across the domestic grid.]

Liddell is scheduled to close in 2023 taking 1.8GW out of the system.

Without sufficient additional power to replace Liddell many lights will go out on summer evenings and probably winter evenings as well. If we want to keep the power on and also lower emissions the only option is nuclear power.

In the evening around dinnertime 30+GW of power is required and the wind supply is critical because the sun has set before the winter peak and it is fading away at that time in summer.

This is the picture showing the dinnertime situation last night.

The critical question is: can the  7GW of new wind in the pipeline cover the loss of Liddell. 

What is 7GW of theoretical (plated) capacity worth at the choke point that can be as low as 2% of plated capacity?

The next display shows that several times a month the supply of wind is less than 10% of the installed capacity for some part of the day.  

The supply through January

The highest point was 56% of plated capacity and the low point was 4.7%

The current 7GW of wind capacity plus another 7 on the way add up to 14GW.

At 10% of capacity that amounts of 1.4GW, compared with 1.7GW provided 24/7 from Liddell.

Battery storage of spare power at the high time of sun and wind is not viable – check the arithmetic for the Musk battery in SA. $60Million to substitute for one wind farm for 20 minutes, equivalent to some 4 minutes for the whole of the state.

Pumped hydro is a mirage, consider the waste of power, the capital cost and the timetable for construction.

Another take on the situation – the % contribution from Wind at 6.30 in the evening from January 1.

6, 5.5, 6, 12, 12.5, 8, 6, 8, 8, 9, 10, 8.5, 5, 6, 10, 14, not recorded, 8, 12, 10, 3.2, 8, 8, 7, 6, 6, 5, 6.

Conclusion. In the foreseeable future (say a couple of election cycles) there is no way for wind power to substitute for coal fired power and any loss of coal-fired capacity will be catastrophic unless some other cost-effective and reliable substitute can be found, preferably before 2023. Nuclear is a strong contender to provide energy security and reduce emissions as well.

Recommendation.  That the problem of the choke point in wind power be explained to politicians and the public so it becomes a topic of serious discussion in political party rooms and elsewhere.


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19 Responses to Choke Point Briefing – Intermittent energy must have 100% backup from conventional power

  1. Zyconoclast says:

    So they cannot use ignorance or lack of advice as an excuse.

  2. Boambee John says:


    Speaking of ignorance and advice to politicians, look at some of tge rubbish being regurgitated about the corona virus.

    The Commonwealth Health (!?!?!?) Minister and all who advise him should all be sacked, same for the fool in Victoria.

  3. Rafe Champion says:

    Precisely Zycon and it is no good for me to send the briefing to every one, to get anywhere near their desks it has to at least come from a constituent and probably from a party worker.

  4. Ben says:

    The states have handed over responsibility to the bureaucracy – initialises such as AEMO, AER, AEMC and any number of transmission and distribution companies.

    The initialisms have national objectives – a state with low power prices will be sacrificed to reduce the power prices in another state eg SA and VIC. The latest billion dollar transmission line approval increases the power transfer capacity between SA and VIC.

    On the face of it, this allows surplus SA wind and solar power to enter the VIC grid, and also allows VIC coal to power SA instead of expensive gas.

    But it also allows more SA price volatility to enter VIC, so when there is no wind and high demand, VIC power price will be increased by the additional demand from SA.

    How do states regain their accountability for their own power system?

  5. Tim Neilson says:

    Rafe Champion
    #3305441, posted on January 29, 2020 at 11:12 am

    Even then the first person to look at it would be a staffer who would be under express instructions not to let the politician see anything which could later be used to show that the politician knew and should have done something.

    You might if you were lucky get a letter confirming that the staffer had seen it and would review it with a view to considering whether the politician needed to be briefed. That would be the end of it.

  6. min says:

    The average punter out there has no idea about electricity, energy or transmission. and politicians are no better. Contact Craig Kelly who might have some ideas S he must feel like he is banging his head against a brick wall . i have met him and he knows the facts backwards.

  7. Rafe Champion says:

    Sorry I mentioned it, lets just do nothing.

  8. Aynsley Kellow says:

    Good post Rafe. The transmission costs and problems are a real issue with renewables. If the capacity factor is 25%, the means there must be transmission capacity of 4x average load – over a widely distributed system. A coal station is likely to be of the order of 80% CF, so the transmission costs of renewables on a system will be at least 3x those for coal – and the lack of density means the distances (and transmission losses) will be greater.
    The choke point issue you highlight is more about renewables feeding into a transmission system not designed for them. I am just pointing to the costs of overcoming the problem.
    Then there is a similar problem with rooftop solar, which leads to lower utilisation of the retail distribution system, not to mention problems of system stability as output varies with passing dark clouds reducing output over urban areas – and then the sunshine increasing again. With large synchronous generators (thermal or hydro) on the system, there is more inertia, but that decreases relative to the increased penetration by renewables.

  9. mark jones says:

    Last year, Alice Springs was blacked out by a cloud. Truthfully reported by the ABC. However, the ABC site has lost the piece…lucky for us..wayback machine got an image

    The outage was caused by a cloud which rolled in to Alice Springs about 2:00pm on Sunday, which caused a “reasonably large increase” to the system, Mr Duignan said.

    An inquiry was called…the outcome…in true socialist fashion! Good thing we are not revolutionary. Why even the need to buffer against solar/wind inefficiency when a simple installation of a gas fired power station..fuelled by the gas field up the road…would keep the lights on without any need to intervene….there is your real time choke point argument, Raff!

  10. mark jones says:

    …that reasonably large increase…is called a cascade failure!

  11. Wilrex says:

    Dust storms stop solar power. The dust is sticky and won’t wash off.
    Loss of power means industry shuts down.
    Loss of income means lower standard of living.
    Repeat above for lack of wind for windmills.
    Add subsidy for going green.
    Subtract subsidy from standard of living.

  12. billie says:

    meh, too complicated

    the ABC and usual media and polly takeaway is climate change bad, renewable good

    there will always be naysayers and conspiracy theorists with complicated ways of explaining things and at anyrate, why would the ABC and environmentlists lie?

    nothing will change this way, the only way I reckon it will change is if there is catastrophic energy failures that no amount of ABC or greenie and polly bullshyte can explain away.

    when it’s out there, and doesn’t affect many people, it doesn’t matter. when it affects everyone, dramatically, then heads will roll (maybe)

    the ABC of course would only change if the energy failure took them off the air and was a global embarassment for them, that seems to drive them more than anything .. that is, what the world thinks of Australia is more important than what Australians think of Australia

  13. Biota says:

    I have no idea what the answer is but it certainly isn’t an appeal to logic, facts and reason. These people are ‘believers’ just look at the ridiculous letter in the previous post by CL. There are clearly huge forces marshaled to impose this on western civilisation and I suspect that it will just have to run its course. The one thing we can be confident of is that the global climate is subject to no one and will undoubtedly have a few tricks to upset things in time.

    I don’t think pushing choke points will get anywhere. Most likely that will just become a feature of the new system and we will all just have to adapt to not having power 24/7.

  14. I_am_not_a_robot says:

    Wind and solar operate at perpetual potential ‘choke points’ and except for remote areas or small ’boutique’ applications they utterly useless and idiotic.
    France has 58, USA 98, Canada 19 safely operating nuclear power reactors many of them for over forty years, Australia with probably the largest single uranium ore deposit in the world has none.
    Go figure as they say.

  15. Rafe Champion says:

    Aynsley as you say, the points you raise concern the cost but they don’t go to the heart of the matter that is sustainability, to coin a term. I suspect that no amount of money will get over the problem of intermittent energy without 100% backup.

    The choke point problem is not about feeding into a system not designed for it. It is about the brutal reality of feeding enough power into the system to keep it alive all the time when there is not 100% backup from conventional power.

    We have never had to face this problem before, it was only last January when there was no reserve with Hazelwood goone, a black coal station failed and some lights went out in Melbourne. Predictably the Minister in Victoria blamed unreliable old coal stations. We know they can go down, that is why we need spare capacity, the blackouts did not demonstrate the fallibility of coal power, they demonstrated its indispensability.

    Contra the people who say it is too bard to explain, unlike the warming argument the choke point argument does not depend on any scientific understanding, it just means explaining the difference between plated capacity of windpower, average capacity (30%) and the lowest points that can be seen at a glance in the relevant display.

    There is a range of imagery available to help – the person who breathes air containing 20% oxygen all their life until they are choked or under water for five or ten minutes; the flow of traffic when multiple lanes are reduced to one, or even by one; the average depth of the ocean is a mile or two but ships are wrecked on rocks in shallow water; running on the rims with no spare tyre in the boot.

  16. I_am_not_a_robot says:

    Blackouts are the best things that can happen at this juncture.

  17. Rafe Champion says:

    Sad but true.

  18. Professor Fred Lenin says:

    We need extended heat to bring down the inadequate power system all over , the backlash will be considerable ,it will put cushy careers in politics and wealthty retirement on a large pension with huge perke and lurks at risk . Nothing gets a career pollie moving like a threat to drag them from the public trough , watch them spring into action when the threat comes , after all who in their right mind would _employ the useless twits in private business?

  19. Jim Simpson says:

    Or perhaps a quicker, easier & more accountable approach is for Oz to adopt a new Energy Policy.

    Industry should be left to decide that which best suits their individual Business Plans (we ought be technology neutral – all options in the mix ie wind, solar, fossil fuels, nuclear, whatever, I don’t care) based upon a simple, clearly defined Energy Policy.
    In the absence of empirical evidence proving the case against CO2 (it’s just an unproven hypothesis based upon speculative computer models), Australia should;
    1. Withdraw from the Paris Climate Accord.
    2. Terminate all Federal subsidies. No favourites! A level playing field.
    3. Introduce 100% Quality of Service (QOS) standards for all energy suppliers (force majeure accepted) to ensure 24h reliability of supply for an essential service.
    4. Clearly define & impose substantial financial penalties upon energy suppliers who fail to meet prescribed minimum QOS ie; Perform, or Perish!
    5. Revisit wholesale pricing to ensure common (fair) to all energy suppliers.
    6. Remove the ban on nuclear to enable industry to make their own decisions as to the merits, or otherwise, of nuclear.
    7. Repeal the Governments Direct-Action Plan & related Safeguard Mechanism legislation that’s driving up Australia’s energy costs.
    If these policies are unattractive to the electricity generators, tough… just re-nationalise the industry & return it to respective State Govts.
    If these principles were adopted, Australia would not need the plethora of parasitic Govt bureaucracies that burden the industry. Just one (the AEMO?), to ensure QOS standards are met, an adequate ROI is provided & substantial penalties applied for any failure to perform.
    Australia would then have a future (as we once did) as a world-class, low cost energy producer. Essential if we’re to compete globally.
    And there would not be any adverse impact upon the world’s climate! Easy!

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