Who are the biggest carbon emitters, in the National Electricity Market?

My recent article about the portfolios producing the most wind production generated a number of comments and questions (both online and offline).

That analysis was compiled because, in the emotive environment of claim and counter-claim with the RET Review underway, it seemed that AGL (in particular) had been painted as all big, bad and dirty (with its significant involvement in wind overlooked).  As shown in our analysis, evidence suggests that AGL has also been a large supporter of wind generation.

Attentive readers would have noted that the title to that article was a question, rather than a statement.

Our article did beg another obvious question – framed with the same “Trader” portfolios (see below) in NEM-Review – who have been the largest CO2 emitters, over time.   Understandably, this was one of the questions we’ve been asked offline.

Hence we cracked open our NEM-Review analytical software today to produce the following trend:

2014-09-03-nem-review-traderemissions

Note in this chart we have selected only the “larger” portfolios, to avoid cluttering the chart.

Otherwise there would be a  significant number of smaller portfolios (some black, some green) with total carbon emissions bumping down near the bottom of the chart.  These portfolios would also show electricity production volumes orders of magnitude smaller than those portfolios shown above (if we charted them).

Within NEM-Review it is possible to sort generation capacity by a number of different criteria – e.g. by region, by fuel type, or by company – through 3 different methods:
1) By Owner (which, as the name suggests, is the company (or companies) that currently own the station).   For a new update on the structure of the generation, transmission and distribution sectors of the industry – in the east and the west see the 2014 Issue “Power Supply Schematic” (now at the printers).
2) By Trader – which incorporates portfolios in terms of the organisations that own the (black) energy produced by the stations.   Similarly, the upcoming 2014 update to the “Power Trading Schematic” might help here.
3) By Bidder – which is similar to Trader, but not for Non-Scheduled plant (i.e. plant that does not bid).

When trending over time, any of these sort mechanisms is assumed not to have changed in the past.   A case in point, here, is that the AGL Energy “Trader” portfolio is shown to include Macquarie Generation, and to assume that MacGen had always been part of that AGL portfolio.  The same for Mt Piper in EnergyAustralia and Eraring in Origin’s etc…

See here for more information about the “Generator Catalogue” within NEM-Review.

As can be seen in this chart, the larger AGL portfolio (following the acquisition of Macquarie Generation) would – with real data trended backwards over time – represent the largest emitter of carbon emissions in the NEM, by a considerable margin.  EnergyAustralia and GDF Suez are shown to be interchanging 2nd and 3rd.

Also notable is the significant reduction shown for the Stanwell Corporation portfolio in the chart above.  Without looking at the details, we suspect this is likely to have been due to a combination of reduced production volumes for the whole portfolio, and the switch from coal to gas at Swanbank E – to be reversed at the end of the year as the LNG plant come on-stream.

So here’s the rub:

AGL can be seen to be the biggest producer of electricity from wind (and by a considerable margin) – but, at the same time, is also the largest emitter of carbon (by a considerable margin).

What does this mean, then, in a political environment persisting with claim and counter-claim about “greenness” – for instance, with:

1)  the recent release of the Greenpeace/TEC “Green Electricity Guide”)?

2)  the “Better Power” campaign launched by (independent?) GetUpI must admit being a bit confused, here, as it refers only to Powershop (whereas there are other retailers also supplying renewable power, if that’s what the customer wants) and yet does not read like a paid advertisement.  Perhaps one of our readers can explain?

In the previous article on AGL and wind, we trended AGL’s “market share” of wind produced (albeit not as clearly as we would like – some comments indicated the confusion inherent in the measure).  For ease of reference this is included here again:

2014-08-22-trendedAGLwindshare-fromNEM-Review

If we did the same with emissions (just AGL’s share of the larger portfolios above), we come up with the following trend:

2014-09-03-trended-emissions-by-portfolio

Comparing the two, we see that AGL’s share of wind production climbed to just above 30% in 2012-13 and 2013-14, whilst its share of emissions (from large portfolios) with the acquisition of Macquarie Generation means that it’s just below 30% (so somewhat lower again as a total share of NEM emissions).  Is this a coincidence?

Another notable observation in the chart above is how emissions from these large portfolios did drop in the carbon tax years (2012-13 and 2013-14), however in some ways this can be seen to be a continuation (perhaps acceleration?) of the trend started in 2008-09 with the start of declining demand.

As always, interested to hear your thoughts – offline (tel +61 7 3368 4064), or with a comment below.


About the Author

Paul McArdle
One of three founders of Global-Roam back in 2000, Paul has been CEO of the company since that time. As an author on WattClarity, Paul's focus has been to help make the electricity market more understandable.

29 Comments on "Who are the biggest carbon emitters, in the National Electricity Market?"

  1. Hi Paul
    Chris, Ben and Waldo from Powershop and Meridian here.

    As you know we are committed to protecting the current level of the RET. You can see many of our comments here.

    GetUp and its members have a similar commitment to the RET, and went through a process to identify retailers with an aligned point of view. They didn’t find many.

    GreenPeace’s guide to which you refer, and Giles Parkinson’s RenewEconomy article , show that there are a number of retailers out there who (regardless of what their marketing teams say about their renewable credentials) work hard at undermining the RET and the renewables industry. Even the more “renewable” amongst the cohort give at most faint praise to the RET, with none coming out hard and unequivocally calling for the RET to be left untouched.

    We have a commercial arrangement with GetUp!, where we pay a stipulated fee to GetUp! for every customer that signs up to Powershop under this campaign, and this arrangement is explicitly disclosed by us at http://www.powershop.com.au/p/betterpower and by GetUp! at https://www.getup.org.au/campaigns/renewable-energy/switch/victorians-switch-to-save-renewables.

    We, and GetUp!, are encouraging customers who favour renewable energy to switch away from Big Three to send an unequivocal message of support for the RET. Whether they switch to us, Diamond Energy, or one of the other renewable retailers highlighted in the Greenpeace guide is not the point.

    We understand that these payments made to GetUp! are going exclusively towards growing the Better Power campaign to save the Renewable Energy Target. The “owners” of GetUp! are the thousands of members who are participating in the campaign, and it’s a not for profit organisation that campaigns to support causes that its members believe in.

    It’s no good to buy renewable energy (GreenPower for example) from a company who is looking to undermine or weaken the renewable energy industry in Australia. It may make you feel better, but it won’t help the future of renewables – because GreenPower only works to support renewables in an environment where renewables are supported by policies like the RET.

    • Hi Chris, Ben and Waldo

      Thanks for the detailed comment. Helps me to understand the nature of the commercial relationship between Powershop and GetUp.

      I think I understand the reasoning behind your comment:


      It’s no good to buy renewable energy (GreenPower for example) from a company who is looking to undermine or weaken the renewable energy industry in Australia. It may make you feel better, but it won’t help the future of renewables

      i.e. buying Greenpower now from someone achieves a 1x benefit (i.e. you buy a kWh you get a kWh) however you’re saying that you buy Greenpower from someone who advocates for the RET as well and there’s a multiplier in there (in terms of supporting growth in renewables beyond just the kWh you pay for).

      My sense is that everyone will have their own personal perspective there – cost per kWh of green would be one consideration for many I suspect.

      Regards

      Paul

  2. We don’t know how much CO2 is emitted because NEM generators don’t measure or estimate with sufficient accuracy and precision at sufficiently fine time intervals (e.g 15 minute intervals as in Europe) the emissions data from the fossil fuel power stations. The AEMO figures are based on long term averages and applied to all units in a power station. They make no allowance for the effects of cycling, spinning reserve, start up and shut down, or operating at less than optimum efficiency.

    This is how Ireland does it for comparison: http://www.eirgrid.com/operations/systemperformancedata/co2intensity/

    [The methodology that used to be described in a succinct, clear paragraph has been removed. I’ve asked for it to be reinstated.]

    • Thanks Peter

      It’s my understanding that the data submitted by the generators to the Department of Environment as part of their reporting requirements is indeed accurate (using international best practice standard).

      This information is not published by AEMO – which, as you know, is a separate organisation focused on electricity as distinct from emissions.

      Data provided in NEM-Review is an approximation based on emissions intensity by station – which, as you say, does not take account of variation by load factor, etc… However it is useful enough for these high-level comparison.

      Paul

      • Paul,

        Thank you for your reply. But my understanding is your understanding is not correct in that Australia does not measure emissions per unit (as the USA EPA requirements [1]. [2]), nor estimate them as is done in EU and as per the example I gave with the EirGrid web site I linked in previous comment. You can see similar web sites for other EU countries too.

        This is why we have only a limited understanding about how much CO2 emissions the intermittent renewable energy generators are achieving. On grids where they have reliable information, such as Ireland which has many important similarities to South Australia, peer reviewed analyses show that wind generation was only about 53% effective at abating CO2 emissions per MWh of wind energy supplied to the grid. That is far less than is claimed by the wind energy advocates.

        [1] US EPA “ECMPS Reporting Instructions Emissions” http://www.epa.gov/airmarkets/business/ecmps/docs/ECMPSEMRI2009Q2.pdf

        [2] US EPA “Plain English Guide to the Part 75 Rule” http://www.epa.gov/airmarkt/emissions/docs/plain_english_guide_par75_final_rule.pdf

        • I received this by email from EirGrid overnight:

          “Thank you for drawing out attention to this. We will ensure that the website is updated in due course with the missing text, which is:
          EirGrid, with the support of the Sustainable Energy Authority of Ireland, has together developed the following methodology for calculating CO2 emissions. The rate of carbon emissions is calculated in real time by using the generators MW output, the individual heat rate curves for each power station and the calorific values for each type of fuel used. The heat rate curves are used to determine the efficiency at which a generator burns fuel at any given time. The fuel calorific values are then used to calculate the rate of carbon emissions for the fuel being burned by the generator. ”

          Australia has no processes that go anywhere near world best practice for calculating or measuring (as the USA EPA requires of US generators), CO2 emissions.

          • Peter Lang, in the end this all matters very little because the National Greenhouse and Energy Reporting System requires measurement of actual coal consumed and sampling analysis of the chemical composition of the coal coming from the field in which it was taken. This provides us with a quite accurate measure of the carbon burnt in total over the period of the year and therefore CO2. At the same time AEMO metering measures the amount of electricity sent out to the grid by the power station. So on an annual basis even if not on a fifteen minute by fifteen minute basis we have a very good understanding of the total annual CO2 emitted and total GWh generated and the average emissions intensity. This then gives us a very good hint as to whether there might be a material deterioration of efficiency at work over time. If this were the case then we might then want to investigate what the cause might be whether it be increased variability of output due to say wind farms (I know what you’re getting at Peter) or for example a change in water content of the coal or some problem with spoiling or a range of other factors.

          • Oh, I see, so we’ve called in the renewable energy advocates to help out on this so called technology site. Confirms what has been evident for a long time.

            Tristan Ellis (Editor of ‘ClimateSpectator’ and a passionate renewable energy advocate), you are wrong on this as has been pointed out many times in the past. Measuring electricity output from each individual generating unit at 15 minute interval and getting a very rough estimate (contrary to your claim) of carbon burnt in power stations over years does not allow the emissions avoided by intermittent renewable energy generators to be determined.

            If such rough estimates are good enough why to the US EPA require measurements of emissions at 15 minute intervals along with calibration of the instruments measuring the emissions and reporting of these to the EPA? Read the links I provided above.

            And why does Ireland (an example of EU method) calculate emissions at 15 minute intervals as per the EirGrid methodology quoted above.

            Also as stated above, EirGrid’s emissions data allow calculation of the emissions avoided by wind generation as just 53% of what they would be if 1 MWh of wind energy avoided the emissions of 1 MWh of the energy displaced from the other generators. It is likely that South Australia’s grid is even less effective than EirGrid.

            And this information is not new or rare. The analyses that have been done based on empirical data (as distinct from modelling studies) show similar results.

            They also show that the higher the penetration of wind energy the lower is the abatement effectiveness.

            What all this means is the CO2 abatement cost with wind energy (and all intermittent renewable energy generators, is much higher (e.g. a factor of ~2 higher) than the renewable energy proponents would have us believe.

            Renewable energy is high cost for no benefit – i.e. no benefit in terms of avoiding climate damages, which is the primary justification for subsidising and mandating them.

          • I’m baffled by your logic, Peter

            Because Tristan has decided to post a comment on WattClarity, it seems that you have inferred (without any other evidence) I asked him to post and ‘gang up on you’.

            Yet you, yourself, have commented a number of times on this post – and you know that I did not ask you to do that. Given I did not ask you, and yet you still posted, I can only surmise that you believe you made your comments because you are my Aunty?

            Furthermore I would conclude, following the same reasoning, that because Giles has chosen not to comment he must indeed be my Grandfather

            Can I remind you of your prior comments posted only last night – that you later requested I delete when the truth became self-evident? This was another example of you jumping to conclusions in attributing motive


            As I have noted before, we have a broad range of readers (including yourself, and Tristan) who choose to comment (or not) of their own volition. As you have seen, most choose not to – we don’t mind, either way.

            Once again I remind you that we are carbon (and technology) agnostic. We post about it occasionally as it is of interest to some of our readers – including, it would seem, you.


            In terms of my article, above, it is not clear to me what value estimations of emissions at 15-minute granularity would achieve in this case?

            Leaving aside the inherent difficulties of actually trying to measure emissions on any basis (and especially on a short-term basis), I am unsure how such measurements, when added together across each of the years shown above, would actually change the main conclusion in the article (that AGL’s larger portfolio produces significantly more emissions than any other portfolio)?

            I have learnt from experience that you have your particular hobby horses that you like to repeat (on WattClarity and other sites) ad infinitum, but it does seem a little off the topic – don’t you think?

            Yes, the emissions calculations uses in NEM-Review are approximations, as we clearly note here.

            Any power station performance engineer will be able to explain why any emissions metric will not be 100% accurate. Calculating estimates on a 15 minute basis such as what you suggest would offer some advantages, but also carry some disadvantages.

            As noted above, NEM-Review is fit for purpose:
            (a) it helps a range of clients compare trajectories of estimated emissions over time, and works with information in the public domain;
            (b) it helps draw out some key points for readers of WattClarity, such as in this post.

            If you want to suggest to Minister Hunt that there are better methods for measurement & reporting of emissions under NGERS, I’m sure he’ll be all ears. You can reach him here.

            If you want to suggest to AEMO that the estimates they publish could be improved, you can find them here.

            I know that some people at AEMO do read WattClarity (though they are probably not the same people dealing with their emissions approximations). I could almost guarantee that Greg Hunt does not read WattClarity. Hence, it’s probably the wrong forum for you to be promoting such suggestions.

            If we ever did come to analyse & post about the emissions avoided by any particular generation source then we might continue this discussion.

            … but for tonight I’ll leave it here and (instead) think about how I would have otherwise worked out the winning lottery numbers if I had not been investing the same time reviewing off-topic comments on WattClarity.

          • Paul,

            I don’t understand the purpose of that long rant. If you didn’t call up Tristan or ‘Anon NGERS worker’ to reply why didn’t you just say so? Instead you went into a long, mostly irrelevant, rant, as has happened before in response to my comments.

            You say WattClarity is technology neutral. Yet it seems pretty clear, from you’re responses and the balance of posts over time, that you are an advocate and supporter of renewable energy. The fact you frequently jump in quickly to attempt to dismiss comments and papers that point out the poor economics, high abatement cost and lack of demonstrable ability to achieve the main justification for subsidising and mandating them also suggests pro renewable energy bias – i.e. not technology neutral after all.

            Your comments in the past responding to the low emissions abatement effectiveness of wind generation (and therefore high abatement cost) suggest you tend to jump in quickly on this issue and make comments that show this is not your rea of expertise. Such comments require a response.

            “it is not clear to me what value estimations of emissions at 15-minute granularity would achieve”

            In that case I’d urge you take some time to read and study the literature on the empirical studies of abatement effectiveness of intermittent renewable energy technologies – or don’t comment on it at all on the subject. You might like to start by studying the Joe Wheatley paper “Quantifying CO2 savings from wind power” because there are relevant comparisons with the South Australian grid http://www.sciencedirect.com/science/article/pii/S0301421513007829 )

            Stating you are carbon and technology neutral may be your intention but you cannot prevent your own biases showing through, just as Tristan and Giles Parkinson can’t help their biases showing through.

          • PS, Peter and others,

            If you wanted to comment to AEMO about their processes for publishing their estimated CO2 emissons figures, then this opportunity has arisen that would might want to contribute to.

            Submissions due 9th October, so would be ideal if we could help you through the power station course before then!

            Paul

        • Gents, I’ve done some work on the marginal abatement I’d like to share with you. In a nutshell I found that due to interconnection, most of the abatement from wind farms tends to be on NSW black coal generators. This is due to the market size and the fact that NSW coal has a higher marginal cost.
          Renewable deployment actually displaced the least amount of CO2 in QLD due to cleaner fuel and modern plant (0.92 kg/kWh). TAS and VIC had the highest amount of abatement at 0.98 kg/kWh due to the market power of brown coal in those regions. SA and NSW were in between.
          This may not seem intuitive but it does line up with some of the fuel consumption info that AEMO or Reputex put out.

  3. In response to comments above here’s how NGERS works:

    Power stations report annually to Government under the National Greenhouse and Energy Reporting Scheme (NGERS).

    Power stations must estimates emissions and energy consumption and production in accordance with the NGER (Measurement) Determination. All medium and large coal and gas power stations estimate CO2 emissions using “method 2 or 3” which involves sampling and analysis of their fuel inputs to determine emission factors. This method results in an accurate assessment of emissions with relatively low uncertainty. Reporting is subject to the NGER framework which includes a system of audit and the publication of certain data (including additional information for designated generation facilities).

    Data reported by power stations are incorporated into Australia’s National Greenhouse Accounts and are used to compile scope 2 emission factors which reflect the average emissions intensity of electricity consumed in each state and territory (published annually in the National Greenhouse Accounts Factors).

    • “which involves sampling and analysis of their fuel inputs to determine emission factors. This method results in an accurate assessment of emissions with relatively low uncertainty.”

      What does “relatively low uncertainty” mean? Please quantify the uncertainty and state how it is calculated.

      The CER figures do not take into account the variations in:
      – C content of fuel being consumed at a point in time
      – thermal efficiency of the different units operating
      – thermal efficiency of the units depending on its output
      – thermal efficiency of the units as their output is ramped up and down

      Perhaps you could state whether all coal fired power stations are using method 1.4 (d) and at what interval are the emissions measured (if not all, what proportion by annual energy generated?):
      ” (d) method 4 provides for facility specific measurement of emissions by continuous or periodic emissions monitoring.”
      http://www.comlaw.gov.au/Details/F2012C00472/Html/Text#_Toc330214226

      The USA EPA requires the emissions to be measured at 15 minute intervals and the measurement instrumentation to be calibrated and all this to be reported to the EPA and publicly available. We have nothing like that.

      Without emissions intensities from each unit, either measured as required in the USA or estimated based on measurements as listed above, assertions about how much CO2 is abated by wind generation are so uncertain as to be meaningless.

      I look forward to your quantification of the uncertainty and explanation of the methodology for estimating the uncertainty. I trust you have reliable estimates for the uncertainties on the assay values of the coal consumed by each unit at 15 minute intervals.

    • Can you provide a link to where I can download the generation and CO2 emissions intensity figures for the NEM generators per 15 minutes (or per 1/2 h or 1 h) to enable the type of analysis reported in this paper:
      http://www.sciencedirect.com/science/article/pii/S0301421513007829
      A pre-submission version is available free here:
      http://docs.wind-watch.org/Wheatley-Ireland-CO2.pdf

      • Peter,
        The power station operators will have to take regular samples of coal quality so they know what the boiler will be experiencing. I don’t know about 15 minute frequency or data availability, but it wouldn’t be hard to report if you are already collecting the data.

  4. I have read with some interest and some amusement.
    I would like to make a few comments.
    Firstly nearly all the reports I have read regarding coal fired power stations and emissions are calculating or estimating their emissions based on the power sold (as shown in the AEMO 5 minute generation data) The fuel used and emissions calculated are estimations reverse calculated, using predetermined efficiencies and moisture content of the fuel. These emissions do not take into account the inefficiencies caused by idling generators to be available to back up wind farms or generator failures. Power stations refuse to publish actual fuel consumption in the same 5 minute time slots that the AEMO publish the generation data for every generator. They have this data but refuse to publish it due to the exposure it would bring on how inefficient they are being forced to run, not only due to backing up wind farms, but also covering line losses pushing power across the countyry. I am told the losses now from Adelaide to Melbourne exceed 15%. AEMO site shows on 4 July 2013 at 14:55, a fault dropped 336 Mw of Macarthur wind farm off line. It was instantly picked up by 334Mw of Black coal fired power station in NSW and Qld. Not a flicker of a light bulb and no blackouts. The coal was being burnt anyway and the load was picked up thousands of km away. Macarthur was not needed so in a net effect was not abating any GHG at all, and was in fact increasing the country’s emissions due to its maintenance and construction cost, and the losses in the power lines across the country to back it up. This backup of wind farm stoppages happens repeatedly, and the AEMO have confirmed that 500Mw and greater backups are needed many times a year.
    If comparison is made from tonnes mined at power station coal mines, where this can be seen on annual reports, and compare it to Mw sold from the same power station, then the numbers are not even close to what they are reported in the theoretical reverse calculations used to report emissions. This discrepancy has been widening steadily over the past 6 years as more wind farm capacity is installed.
    And finally, I talk to power station engineers and to contractors working on the sites. Engineers tell me that their coal feed does not reduce and increase at the same rate as MW sold, in some cases they can be burning 20% more coal than what the Mw being sold. A contractor working on a Black coal infeed conveyor told me how they were under pressure to keep the conveyors running during a maintenance job, the coal was continually fed into the generator boiler for the 4 or 5 hours of the job. Even though the coal feed remained constant, comparing AEMO generation data, the output nearly doubled then again halved over the period. A lot of coal was not being converted in to saleable electricity, it was wasted.
    Opinions, thoughts and estimations are wasting so much time and money, we need the power generators to openly publish real time 5 minute coal feed data for every generator, so this can be matched against the AEMO 5 minute generation data, then we can all see what is happening in an open honest and truthful manner. Then we can clearly see how much coal is really being burnt, and how small the net emission savings by wind farm are.

    • Ah, Hamish (and Peter Lang)

      Everyone loves a good conspiracy theory.

      Problem is, most of them do turn out to be myths (though I am sure that Elvis is still out there, somewhere).

      Whilst we could go to-and-fro electronically for a long time, and we might achieve a raised level of understanding eventually, it would not be a very efficient use of my time, or yours. Instead, I have another suggestion:

      For a number of years, QUT has run an excellent Introduction to Power Plant Course that has helped to lift the veil on the magic that happens behind the closed doors of a power station.

      Such a course would (for instance) help you understand how unit coal bunkers stand between coal supply from larger station bunkers and/or the mine, and provide some hours of storage to enable coal burn rate to be modified over short time periods without necessarily changing coal feed rate into the bunkers.

      Such a course would (for instance) help you understand the difficulty of accurately weighing the amount of coal fed into a boiler (let alone the problems in accurately measuring CV and other qualities) on an ongoing basis.

      It would help you understand how spinning reserve operates at a station, and how it provides the capability on the NEM grid to recover rapidly from frequency drop that would follow any large station outage (be it wind, coal, gas, whatever).

      Both you, and Peter Lang, do seem to have made considerable effort to start from nothing and learn what you can about how thermal coal-fired power stations. Such a course would build on this base to help you to understand how one actually works.

      In the interests of saving my time on WattClarity, and helping you both up the learning curve, I would be happy for our company (GLOBAL-ROAM Pty Ltd) to contribute $1000 each to the cost of you attending this course. Perhaps some of our other readers would like to chip in as well?

      However note that:

      1) There would be some cost remaining to you to pay (depending on how much our other readers volunteer to chip in). Given the concerted efforts I have seen by both of you make to contribute to the discussion about the NEM’s power system, I am sure you will feel this investment in completing your education to be very worthwhile indeed.

      2) More seriously (and sadly), though, the person who had played a huge role in delivering this course over a number of years (Mr Graham Proud) was killed in a car accident only a few weeks ago. I am not aware of what QUT will do to find someone to step into Graham’s huge shoes, but will be happy to follow up with them to find out, if this proposal is amenable to either, or both, of you. If this course cannot be run, I will endeavour to find another one for you that will deliver real knowledge.

      Please advise if you will accept this offer to assist in your education?

      Paul

    • Hamish,
      Whoever you are talking to is bullshitting you.
      1. There are no formal reserves as backup for wind. Trips on thermal generators are far more common (see Liddell, Eraring) and yet still no problem with security. Also note that SA has no new fossil generators despite massive WF capacity. WF output can reach 90% of load served.
      2. Transmission losses are usually 2-5%. If they were 15% it would be economically attractive to build power plants in the CBD.
      3. Fossil plant burn less fuel at lower capacity. From thermo law 1: energy in = energy out for a system with constant internal energy. If the plant was burning the same amount of fuel for a lower output they would need to actively cool the boiler to prevent damage (i.e. increasing internal energy). It is much easier to feed less fuel in (not to mention cheaper). The efficiency at min load is similar to that at 100%. Peak efficiency is at ~80%. Note that even if efficiency drops 1% when you halve your output, you are still burning about half as much fuel. Thus if a WF’s output forces a coal plant to turn down (nearly always the case) you still get 98-99% of the savings.

      • Hi Tom

        Regarding your points:

        1) About reserves

        In terms of spinning reserve, I noted here how cost of spinning reserve has not increased with wind – however I also noted that there is still a cost of intermittency (currently being manifest as a wealth transfer from existing thermal generators to wind farms). Seems to me that it’s only one instance – in many, on all “sides” – of “socialising costs whilst privatising profits”.

        Trips to thermal generators do indeed occur (and trips to entire wind farms would seem unlikely, due to the scattered nature of them – i.e. off the top of my head, I could only see a whole farm tripping if the main connection substation (or control system) had problems, whereas in a thermal station there are many more potential failure points to take a unit offline).

        However, I think Hamish is speaking about the more frequent intermittency, as seen through capacity factors (though perhaps he could not put this into the right technical words) .

        Statements about % of energy served from any particular fuel source in any particular geographical location, or “no new fossil generators” in SA (whilst understandable from a political point of view) are largely irrelevant. That’s the point of our National Electricity Market.

        2) About losses

        Losses depend on a number of things, including the distance travelled. There are instances where losses can be up to 20%, say, in the extreme. The AEMO documentation on Loss Factors & Regional Boundaries explains more. Note these are marginal losses, not average losses (which will be lower).

        3) About heat rate

        Fact 1 – You have noted (as did I) that coal consumption varies, significantly, with output.

        Fact 2 – You have also noted that heat rate also varies with output, which is true. It’s even more complicated than that, because heat rate can vary over time (due to super-heater tubes being fouled with slag, condenser tubed becoming partially blocked, and a whole range of other reasons) and does vary (even as-new) with different configuration of plant (e.g. for a certain output it might be possible to have 4 mills running, or 5 – both configurations will yield different heat rates).

        From what I have read, some people seem to latch onto Fact 2, and overlook Fact 1 – whilst some people do the reverse.

        It is understandable that an outsider might see Fact 1 and Fact 2 opposed.

        Finally, Hamish, one of the main reasons some generators may not want to have such commercial details as coal burn & heat rate published in real time is because of the highly sensitive commercial in confidence nature of the information. If their competitors knew this type of information, they might be able to utilise it for commercial gain (and their detriment) in the market (in our software development business, we’d certainly be looking to further enhance ez2view to help them do this, if possible!)

        Hope this helps?

        Paul

  5. Paul,

    Wow! What a pathetic, arrogant, gratuitous response. It demonstrates many of the signs of intellectual dishonesty (more below)

    So Paul McArble is resorted to offering ‘shut up and go away money’ and for it to be paid by ROAM Consulting.

    This smacks of similarities to corrupt union behaviour. What’s next, banned from any further comments? That’s how his evident allies, Tristan Edis and Giles Parkinson (name first mentioned here by Paul McArdle, not me), prevent comments they don’t want rather than admit they are wrong on an issue. Anonymous commenters also appear on Tristan Edis’s politically partisan, renewable advocacy web site to defend WattClarity. So there is an apparent allegiance between these passionate (but irrational) renewable energy activists.

    No 4 of the “10 signs of intellectual dishonesty” is:
    “4. Avoiding/Ignoring the question”
    http://judithcurry.com/2013/04/20/10-signs-of-intellectual-honesty/

    Instead of admitting you made baseless assertions and you cannot support them you try to bluff your way around it. You’ve demonstrated this type of response on previous occasions too when you made comments that showed you don’t know what you are talking about on the issue of how Australia’s CO2 emissions are estimated and the uncertainties in the estimates.

    You also admitted, on this thread, you don’t understand why measurements at time intervals of 15 minutes (or 30 minutes maximum) are relevant for estimating the CO2 emissions avoided by intermittent renewable energy generation. [I pointed you, again, one of many papers which shows why very clearly; apparently you never read it or didn’t understand it, or any of the others]. And you seem to go into a state of denial whenever it is pointed out that the empirical evidence from other grids where such information is available (on CO2 emissions per individual unit per 15 minutes taking into account the thermal efficiency at the level of output for that particular unit at that time) shows that wind generation is much less effective than the proponents claim at abating CO2 emissions.

    One such study shows that Ireland’s EirGrid was just 53% effective at abating CO2 emissions in 2011 (Wind generation supplied 17% of electricity and many relevant features of EirGrid are similar to South Australia’s grid which is held up by the wind energy advocates and activists as the poster child for renewable energy in Australia.

    That means that CO2 abatement using wind energy is about twice as expensive as the proponents would have us believe. That is relevant. Why are Paul McArdle, Tristan Edis and Giles Parkinson trying t avoid the issue. Why are they trying to bury it? Why is Paul McArdle offering ‘shut up and go away’ money – which is to be paid by ROAM Consulting.

    Why don’t you just answer the questions and provide links to the 15 minute data, the actual consumption and the assay values of the coal entering the burners at 15 or 30 minute intervals? We know the reason – they don’t exist. You know it too and are trying to doge admitting you are wrong and made baseless assertions up thread.

    Avoiding/Ignoring the question”
    http://judithcurry.com/2013/04/20/10-signs-of-intellectual-honesty/
    Is just one of the 10 signs of intellectual dishonesty displayed by Paul McArdle.

    • Peter

      I’m sorry to see that (for the 3rd time in a few days) you have jumped to conclusions – this time in assuming some nefarious ulterior motive in a genuine offer to help.

      It’s unfortunate that we cannot help you.

      Paul

      PS Hamish, we would still happily help you.

      • Point one,

        Your “offer” is not a genuine offer at all. It is an attempted diversion from answering the question to get you off the hook and appeal to your followers. If it had been genuine it would have been done quietly by email. Your comments are arrogant, insulting and rude. You haven’t a clue what I’ve been working on for the 40 years before retirement (including having been on and in the dams, tunnels and power stations of the Snowy Mountains Scheme since about 1952, aged about 6). Whereas you comment, and try to make out you speak with authority, on subjects you clearly know little about. They suggest you are young, inexperienced and gullible.

        You still avoided the questions. They are relevant to the debate which followed from your post and my first comment “We don’t know how much CO2 is emitted because NEM generators don’t measure or estimate with sufficient accuracy and precision at sufficiently fine time intervals (e.g 15 minute intervals as in Europe) the emissions data from the fossil fuel power stations”

        Which you really didn’t have to answer at all since you seem to know next to nothing about the subject.

        As I pointed out, your comments and avoidance demonstrate intellectual dishonesty – e.g. “10 signs of intellectual dishonesty”, No 4 here: http://judithcurry.com/2013/04/20/10-signs-of-intellectual-honesty/

        I don’t know why you, as the blog owner, just drop it – don’t respond at all on subjects you know next to nothing about.

        At this point I am persuaded your personal, professional and intellectual integrity is not very high.

  6. As I suspected, my response has gone straight to moderation.

  7. Well, what can I say. You want to glide over facts, first hand from people on the ground (with no vested interests) and assume that no one but you has any knowledge or contacts that know more than you are prepared to admit. Some comments to correct your assumptions. The conveyor was feeding the actual boiler, not a stockpile, if you read my original comment closely. PowerStation engineers with 35 years service as I understand, with considerable first hand experience running the stations tell me excess stream is vented, to put it simply, so that capacity is available with live hot available steam at any time. You are probably unaware that I personally worked in facilities that provided standby and peaking power to the grid, and are probably unaware that I worked under contract for state and federal ministerial advisers on a couple of high level energy projects for their American, Japanese and Chinese friends. I could probably run a course that could teach you a thing or two.
    As for “commercial in confidence” being the reason why they won’t supply the coal feed figures, you must be joking. Anyone in the industry would have a very accurate idea of what all other powers stations in the grid are capable of, and their efficiencies and capabilities are published in annual reports. There is no real excuse for not publishing live coal feed data, unless you are trying to hide reality.
    And as for SA, they more often than not are backed up by Victorian Brown coal generators. With industrial and manufacturing downturn, Victoria has an enormous unused capacity available to be sent anywhere in the Eastern states. Even allowing for considerable losses.
    Tom interesting that you said “Transmission losses are usually 2-5%. If they were 15% it would be economically attractive to build power plants in the CBD.” Firstly if you seriously believe transmission loss from Qld to SA is less than 5%, then I have little faith in your understanding of the NEM or the impact wind farms are having. The Singaporean company who own the 500Kva line that runs through to Portland, currently are looking at the maintenance or upgrade that is required, because it has hit the 15% l.oss figure. They are also costing and in early stages of planning permissions, to construct a line beside the existing one with twice the capacity. The drawings have already been done for the power station to be built at Portland as well. And it is not a wind farm and it is not fossil fuel powered. If you do a search on the speech made a couple of years ago by the then federal Labour energy minister, you will see that the Federal Government stated then, that when the country finally realises that wind will not work, then they can build the new power station and all the Green voters will accept it, and we will have built the grid and interconnectors on the pretence of wind saving the world, to enable the power station to run the country. However today I was told that it may not be built in Portland now that there is a mothballed desalination plant in Gippsland that just happens to be a good size fit for the desalination plant required for the proposed power station. This significantly reduces the cost required to build the power station. Also for Melbourne, prevailing winds and weather would be safer having the power station next to the desalination plant, rather than at Portland. I am afraid that wind farms are just a distraction for the masses, so the government can implement the goal with less fuss. Not a conspiracy, not a work of fiction, the drawings have been complete for some time now, and both state and federal planners are fully briefed on the plan. If you personally know people in these departments as I do, then they can confirm this to you. If you do not know people in these departments, and have not seen the drawings, then you have no right to comment on it nor cast doubt on the credibility of those of us that have. I do not plan to make any further comments on this matter.

    • Cycle steam is not vented except in emergencies. Demin water costs too much.

      I agree, SA WFs are often backed up by VIC brown coal. While the coal plant is run at a lower capacity it is consuming significantly less coal. That’s the whole point.

  8. Wow, normally there are harldy any comments on here but for some reason this post has released not one but two nutters!

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