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  1. #1361
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    [QUOTE=Snoopy;862848]I think you need to keep in mind Jantar's post on the cost structure of the industry below:



    IMO the way the cost structure is set up in the industry, people who attempt to generate their own power are effectively screwed.

    The gentailers will screw you because they can and want to
    Both my houses have had solar installed .
    My gentailer -contact energy -after months have still not installed the import/export meter .
    So I am looking at changing to Flick who pay the wholesale price-Jantars post is very helpful in calculating the current wholesale price I would receive-or Genesis-who pay more than contact.
    What I am enjoying is 5kw of free power during the day with aircondtioning,pumps,swimming pool etc operating-a lot more fun than exporting to our miserly gentailers !
    I might sell my contact shares as well (definitely keeping Mercury)

  2. #1362
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    Default Geothermal Plant Utilisation (Sept 2020 quarter)

    Quote Originally Posted by Waltzingironmansinlgescul View Post
    What are the geo thermal stats producing at the moment?
    You can get the latest quarterly operating report for Mercury, which covers the quarter ended 30th September 2020 here:

    https://www.mercury.co.nz/documents/...-q1-final.aspx

    On page 2 titled 'Operating Statistics', 'Consolidated Geothermal Generation' for the three month period is listed as 687GWh = 687,000MWh/quarter

    The geothermal generation capacity at Mercury is 466MW (My post 1347). If run at 100% capacity for three months those five geothermal stations can generate:

    466MW x 24 hrs/day x 92 days/quarter = 1,028,928 MWh/quarter

    So currently the Mercury geothermal stations are operating at: 687,000 / 1,028,928 = 66.8% capacity

    That does seem low to me., if the long term average that Mercury is seeking to maintain is nearer to 94% capacity utilisation.

    SNOOPY
    Last edited by Snoopy; 18-12-2020 at 08:25 AM.
    Industry shorthand sees BNZ employees still called 'bankers' but ANZ employees now called 'anchors'. Westpac has opted out of banking industry shorthand...

  3. #1363
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    Default Geothermal Plant Capacity Utilisation (FY2020 )

    Quote Originally Posted by Snoopy View Post

    That does seem low to me., if the long term average that Mercury is seeking to maintain is nearer to 94% capacity utilisation.
    By going back to the previous quarterly report, I am able to calculate the geothermal plant utilisation for the previous 12 months (FY2020)

    https://www.mercury.co.nz/documents/...-q4-final.aspx

    On page 2 titled 'Operating Statistics', 'Consolidated Geothermal Generation' for the three month period is listed as 2,615GWh = 2,615,000 MWh/quarter

    The geothermal generation capacity at Mercury is 466MW (My post 1347). If run at 100% capacity for twelve months those five geothermal stations can generate:

    466MW x 24 hrs/day x 365 days/quarter = 4,082,160 MWh/year

    So the Mercury geothermal stations, over FY2020, operated at: 2,615,000 / 4,082,160 = 53.0% capacity

    What??!!!?

    Now I have to question my assumptions about the utilisation of these Geothermal stations. Where did I get my 94% figure from? I go back to the original MRP Prospectus p49

    "Geothermal energy generation provides steady base load supply that is not subject to climatic conditions that typically influence other renewable electricity supply. Geothermal power stations in New Zealand run at full generation output approximately 95% of the time."

    Yes, I double checked. That is what the MRP (now MCY) prospectus said. Why is the actual Geothermal capacity utilisation at Mercury so far below what the prospectus suggested? Normally in this situation with the figures so far out, I would think that I have made a mistake in my calculations. But considering I have just got a similar result on two separate calculation occasions, I fear I am correct ;-(. Can anyone explain?

    SNOOPY
    Last edited by Snoopy; 18-12-2020 at 08:14 PM.
    Industry shorthand sees BNZ employees still called 'bankers' but ANZ employees now called 'anchors'. Westpac has opted out of banking industry shorthand...

  4. #1364
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    Thank you MR S we shall enjoy reading your post perhaps later today. Production of energy in NZ is im afraid something we have not paid enough attention too. Busy morning with a lot of software to test and connect to market data and platforms.

    It may be that the number of statistical number crunchers in NZ is limited and that is why MR S you might be one of the few outside institution source of research.

    Its not like research papers are going to be released if they dont have to.

    If MR S modelling is correct an EV fleet can be powered NOW. Which mean surely the government knows this and simply does not want to deflate certain sectors of the economy over night.

    Pretty damning really that NZ is stuck with an old polluting fleet because the status quo is jobs. Its understandable if you want to stay in government.

    Interesting that Deep Mind AI Platform in the UK for energy has been disbanded and the national grid plans to use it for helping with energy use was never implemented. So much for AI in the real world....also the prices being charged were not real world, rather out of this world and UK balked ... whole energy unit at deep mind was canned...
    Last edited by Waltzingironmansinlgescul; 18-12-2020 at 08:03 PM.

  5. #1365
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    Default Geothermal Plant Capacity Utilisation (FY2016 )

    Quote Originally Posted by Snoopy View Post
    By going back to the previous quarterly report, I am able to calculate the geothermal plant utilisation for the previous 12 months (FY2020)

    https://www.mercury.co.nz/documents/...-q4-final.aspx

    On page 2 titled 'Operating Statistics', 'Consolidated Geothermal Generation' for the three month period is listed as 2,615GWh = 2,615,000 MWh/quarter

    The geothermal generation capacity at Mercury is 466MW (My post 1347). If run at 100% capacity for twelve months those five geothermal stations can generate:

    466MW x 24 hrs/day x 365 days/quarter = 4,082,160 MWh/year

    So the Mercury geothermal stations, over FY2020, operated at: 2,615,000 / 4,082,160 = 53.0% capacity

    What??!!!?

    Now I have to question my assumptions about the utilisation of these Geothermal stations. Where did I get my 94% figure from? I go back to the original MRP Prospectus p49

    "Geothermal energy generation provides steady base load supply that is not subject to climatic conditions that typically influence other renewable electricity supply. Geothermal power stations in New Zealand run at full generation output approximately 95% of the time."

    Yes, I double checked. That is what the MRP (now MCY) prospectus said. Why is the actual Geothermal capacity utilisation at Mercury so far below what the prospectus suggested? Normally in this situation with the figures so far out, I would think that I have made a mistake in my calculations. But considering I have just got a similar result on two separate calculation occasions, I fear I am correct ;-(. Can anyone explain?
    I have gone back in time to FY2016. This is the first twelve month time period with the geothermal power station line up at Mercury exactly as it is now.

    https://issuu.com/mercurynz/docs/qua...54184/37453359

    On page 2 titled 'Operating Statistics', 'Consolidated Geothermal Generation' for the three month period is listed as (2,596 + 234) GWh = 2,830,000 MWh/quarter

    The geothermal generation capacity at Mercury is 466MW (My post 1347). If run at 100% capacity for twelve months those five geothermal stations can generate:

    466MW x 24 hrs/day x 365 days/quarter = 4,082,160 MWh/year

    So the Mercury geothermal stations, over FY2016, operated at: 2,830,000 / 4,082,160 = 69.3% capacity

    That is better but still not near 94%. The following statement is on p1of the report

    --------------------

    HIGHEST ANNUAL GEOTHERMAL PRODUCTION IN COMPANY HISTORY: Geothermal generation for FY16 was the Company’s highest ever at 2,830GWh (up 2% on FY15) due to availability of 95.5% over the year and the impact of the turbine replacement at Nga Awa Purua. For the quarter, geothermal generation was down slightly on pcp to 702GWh, due to maintenance activity at Ngatamariki.

    ---------------------

    Right so it seems Mercury had a record generation year with 69.3% of geothermal capacity used. Yet availability was 95.5%. I don't understand. If the geothermal power plants were available for 95.5% of the time, why were they not used that much?

    SNOOPY
    Last edited by Snoopy; 18-12-2020 at 08:15 PM.
    Industry shorthand sees BNZ employees still called 'bankers' but ANZ employees now called 'anchors'. Westpac has opted out of banking industry shorthand...

  6. #1366
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    Possibly the cost of generation is higher than other sources so why run your Geo plant if you can make more profit by supplying from a different source. Also presumably at times itís not needed. So available to generate but not required.

  7. #1367
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    Quote Originally Posted by Snoopy View Post
    ….. and the impact of the turbine replacement at Nga Awa Purua. For the quarter, geothermal generation was down slightly on pcp to 702GWh, due to maintenance activity at Ngatamariki. ….

    SNOOPY
    Here are two reasons why availability of 94% was not possible. Turbine replacements take quite a bit of time, and NAP is a very large machine. I cannot see anyway that MCY could claim 94% availability.

  8. #1368
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    This is the most interest thread to read and im really rather P.SS.D that we dont trade this stock the last few months... We are thinking of investing in some off shore battery raw material instead... The rest of the world may not be as well supplied with natural energy resources as NZ. AUS has some interesting plays on this sector investing in Mines for battery raw materials.

    Our understanding is that there is a polluting lubricant in the actual turbine and research is underway in europe to reduce or replace this lubricant that can cause pollution from wind turbine operations in some cases.
    Last edited by Waltzingironmansinlgescul; 19-12-2020 at 07:16 AM.

  9. #1369
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    Quote Originally Posted by mondograss View Post
    Possibly the cost of generation is higher than other sources so why run your Geo plant if you can make more profit by supplying from a different source. Also presumably at times it’s not needed. So available to generate but not required.
    Thanks for the responses. The image I had was of these geothermal stations grinding away 24/7 (except for the servicing requirements of course) and everything else would be switched off first to deal with any surplus power generation. Part of my reasoning for thinking that way was to avoid the thermal stress (not to mention the mechanical stress) of turning the geothermal turbines and the associated hot liquid piping systems on and off. But I am not really sure how much the power load does drop off at night. Maybe turning off the hydro is not sufficient? There is still too much power being generated? Anyone know?

    Hydro generation is definitely cheaper than geothermal generation on an incremental unit power basis. But that isn't the whole picture. At peak times the generation capacity of hydro is not sufficient to meet power needs. So turning a geothermal turbine off at low load times might make instantaneous economic sense. But by doing so you have the extra wear and tear of turning such a system off and on every day. Over a whole year that might be more expensive that just keeping the geothermal turbine running 24/7. There would also be mechanical wear and tear on the hydro turbines turning those on and off, that is true. But there wouldn't be any thermal stress in doing that. So by my way of thinking, if the load varies it is the hydro turbines you want to turn on and off, not the geothermal turbines.

    Quote Originally Posted by Jantar View Post
    Here are two reasons why availability of 94% was not possible. Turbine replacements take quite a bit of time, and NAP is a very large machine.
    Yes, Nga Awa Purua is the largest of Mercury's geothermal stations. I would imagine the turbine replacement would have required significant downtime. The only problem with that theory is that in the subsequent year, when no such major overhaul project was done, total geothermal energy produced was less (Down from 2830GWh to 2809GWh).

    Quote Originally Posted by Jantar View Post
    I cannot see anyway that MCY could claim 94% availability.
    I gave you the reference

    https://issuu.com/mercurynz/docs/qua...54184/37453359

    The claim is 95.5% availability

    Another factor crossed my mind after reading footnote 3 p2 of the operational report for Q4 FY2019

    https://issuu.com/mercurynz/docs/mer...54184/63216371

    "Geothermal Consolidated: Includes Mercury's 65% share of Nga Awa Purua"

    By omission then, that total of 2564GWh doesn't include the 35% share of Nga Awa Purua not owned by Mercury. If Mercury is not counting the share of geothermal generating capacity it doesn't own, then the figure I am using as my base for 100% generation is wrong and too high

    ------------------------------

    Mercury Energy Geothermal Station Generation Capacity Notes Mercury Energy Geothermal (Equity Accounted) Station Generation Capacity (Equity Accounted) Notes
    Rotokawa 34MW Refurbished FY2015 Rotokawa 34MW Refurbished FY2015
    Ngatimariki 82MW Completed FY2014 Ngatimariki 82MW Completed FY2014
    Kawerau 100MW Kawerau 100MW
    Mokai (25% owned) 112MW Mokai (25% owned) 28MW
    Nga Awa Purua (65% owned) 138MW Completed FY2010 Nga Awa Purua (65% owned) 90MW Completed FY2010
    Total 466MW Total 334MW
    Effective Capacity Factor 0.940 Effective Capacity Factor 0.940
    Total Operationally Adjusted 438MW Total Operationally Adjusted 314MW

    ---------------------------

    Let's rerun the calculation for FY2016 using the new lower equity accounted generation base

    The geothermal generation capacity at Mercury is 334MW (table above). If run at 100% capacity for twelve months those five geothermal stations can generate

    334MW x 24 hrs/day x 365 days/quarter = 2,925,840 MWh/year

    So the Mercury geothermal stations, over FY2016, operated at: 2,830,000 / 2,925,840 = 96.7% capacity

    What do you think? Could I be onto something? The only problem is that this 96.7% figure is even higher than the 95.5% figure that Mercury claim. Hmmmm

    SNOOPY
    Last edited by Snoopy; 19-12-2020 at 08:36 AM.
    Industry shorthand sees BNZ employees still called 'bankers' but ANZ employees now called 'anchors'. Westpac has opted out of banking industry shorthand...

  10. #1370
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    I think youíre on to something. 2016 was a leap year so 366 days not 365, which brings you down to 96.4% I think.

    I also wonder if itís as simple as on or off though. Perhaps more likely thereís a low, slow idle state that minimizes both stress and costs but doesnít produce much output either.

  11. #1371
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    Quote Originally Posted by Snoopy View Post
    Let's rerun the calculation for FY2016 using the new lower equity accounted generation base

    The geothermal generation capacity at Mercury is 334MW (table above). If run at 100% capacity for twelve months those five geothermal stations can generate

    334MW x 24 hrs/day x 365 days/quarter = 2,925,840 MWh/year

    So the Mercury geothermal stations, over FY2016, operated at: 2,830,000 / 2,925,840 = 96.7% capacity

    What do you think? Could I be onto something? The only problem is that this 96.7% figure is even higher than the 95.5% figure that Mercury claim. Hmmmm
    Would the Mercury availability figure be calculated that way, or is that just how you are estimating it because you don't have access to the actual data on how long each geothermal station was offline during the year?

    I think geothermal generation is slightly seasonal: higher production in cold winter months than in hot summer months. If you calculated availability just by how long the station is offline in a year then that would not be affected by when in the year it was offline. But if you calculate from the total GWh output for the year as you are doing then you might get different results depending on whether the outage was in winter or summer. I don't know if that would be enough to account for the discrepancy though.

    Edit: OK I see in the 2016 FY results presentation Mercury claim 95.5% availability, which is equivalent to downtime of 16.5 days out of 366 maximum. But your calculation is in terms of energy, i.e. a loss of 95.84 GWh out of 2925.84 GWh maximum. So to convert the energy figure to days of downtime would depend on whether the downtime was in winter or summer. A shorter winter outage might lose the same amount of power as a longer summer outage. (Due to the lower thermal efficiency during summer.)

    And to complete the process, although there will likely be a large error due to rounding: 95.84 GWh / 16.47 days = 242 MW, so it seems to be in the realm of possibility that your calculation of 96.7% on a lost energy basis does work out equivalent to Mercury's 95.5% availability on a downtime basis, with the downtime occuring mainly during the summer months.
    Last edited by turnip; 19-12-2020 at 02:50 PM. Reason: trying to explain myself better.

  12. #1372
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    [QUOTE=fish;863116]
    Quote Originally Posted by Snoopy View Post
    I think you need to keep in mind Jantar's post on the cost structure of the industry below:



    IMO the way the cost structure is set up in the industry, people who attempt to generate their own power are effectively screwed.

    The gentailers will screw you because they can and want to
    Both my houses have had solar installed .
    My gentailer -contact energy -after months have still not installed the import/export meter .
    So I am looking at changing to Flick who pay the wholesale price-Jantars post is very helpful in calculating the current wholesale price I would receive-or Genesis-who pay more than contact.
    What I am enjoying is 5kw of free power during the day with aircondtioning,pumps,swimming pool etc operating-a lot more fun than exporting to our miserly gentailers !
    I might sell my contact shares as well (definitely keeping Mercury)

    i can highly recommend ecotricity.

    i have been using them for quite some time and significantly better both as a consumer or for exporting as with solar than any of the gentailers.

    https://ecotricity.co.nz/

  13. #1373
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    Quote Originally Posted by mondograss View Post
    I think you’re on to something. 2016 was a leap year so 366 days not 365, which brings you down to 96.4% I think.

    I also wonder if it’s as simple as on or off though. Perhaps more likely there’s a low, slow idle state that minimizes both stress and costs but doesn’t produce much output either.
    Geothermal is either on or off. There is not really an between setting. When a geothermal machine is reduced in load the steam field is still trying to produce steam. That steam either has to be vented with noise and pollution issues, or one or more steam bores have to be shut down. When a bore is shut down, the pores fill with silica which precipitates out of the geothermal fluid and they block up. Once the bore is opened again it never gets back up to full production.

    When I was a system controller, 30 odd years ago, we were told that any controller who instructed geothermal to reduce load, other than for an outage, would be sacked.

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