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Grid Integration of Large-Scale Renewables

  • 07-11-2011 2:22pm
    #1
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    Until technology gives us an efficient affordable way to store energy, wind power & wave power and all the other alternative technologies will have limited use. The idea of wind or wave power is seductive, but their unreliability makes them of little practical use.

    [MOD]This thread was spawned by another thread.[/MOD]


«134

Comments

  • #2
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    From the ESB Sustainability Report 2010 here page 13:

    http://www.esb.ie/main/sustainability/sustainability-report-2010.jsp

    "At the end of 2010 we had 5.6 GW of generation of which 4.5 GW were located in the SEM. We have expanded our wind portfolio and at end 2010 had 235 MW of capacity installed and a further 95 MW under construction. This adds to our 217 MW of hydro and 292 MW of pumped storage capacity."

    Less then 5%! and that is only installed wind capacity, not actual amount generated which would be much less than that. The wind does not blow all the time. The same trap that the planners in the UK make as they have to take into consideration the installed capacity rather that actual production. Wheras power stations can generate actual=installed capacity on a constant basis. That is why renewable energys need storage and are therefor one and the same issue. Not sure where you get your figures from.


  • #3
    L
    Registered Users Posts: 655 ✭✭✭L


    easychair wrote: »
    Until technology gives us an efficient affordable way to store energy, wind power & wave power and all the other alternative technologies will have limited use. The idea of wind or wave power is seductive, but their unreliability makes them of little practical use.

    Simply not true. Stop assuming that variable means unreliable/unpredictable.

    Even using a (bloody awful) persistence forecast, you're looking at a time horizon where you know your wind generation to within 20% for six hours ahead and that's the most naive forecasting method you could possibly assume short of just guessing.
    djpbarry wrote: »
    However, this has to be balanced against the fact that the manner in which electricity is currently produced and consumed needs to change pretty quickly, as it’s obviously not sustainable.

    Yeah, but there's much better halfway houses than storage. Until we actually get to the point where storage is useful, we want to be investing in things that will actually allow us to reach the wind penetrations we want.

    More CAES gas turbines, more interconnection and better demand control. Not storage.


  • #4
    L
    Registered Users Posts: 655 ✭✭✭L


    Oldtree wrote: »
    "At the end of 2010 we had 5.6 GW of generation of which 4.5 GW were located in the SEM. We have expanded our wind portfolio and at end 2010 had 235 MW of capacity installed and a further 95 MW under construction. This adds to our 217 MW of hydro and 292 MW of pumped storage capacity."

    Less then 5%! and that is only installed wind capacity, not actual amount generated which would be much less than that.

    ...That's just the ESB's own assets not all the wind power in the country mate. You want to look at Eirgrid figures.

    At this second (as in real time data) we have demand of 3705MW with 562MW of wind generation - about 15% on a not particularly windy day. I've seen this figure as 1400MW of Wind and a 50% penetration before.


  • #5
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    L wrote: »
    Simply not true. Stop assuming that variable means unreliable/unpredictable.

    Its ironic indeed that you tell me to stop assuming something which you assume I am assuming. Which I am not.

    Last winter, when the freezing temperatures created a peak demand for power, the wind across Ireland ( and the UK) didn't blow, and the contribution made by wind power to the national grid was virtually zero. Hence wind power is unreliable meaning, simply, it can't be relied on.


  • #6
    L
    Registered Users Posts: 655 ✭✭✭L


    easychair wrote: »
    Its ironic indeed that you tell me to stop assuming something which you assume I am assuming. Which I am not.

    Last winter, when the freezing temperatures created a peak demand for power, the wind across Ireland ( and the UK) didn't blow, and the contribution made by wind power to the national grid was virtually zero. Hence wind power is unreliable meaning, simply, it can't be relied on.

    Reliability means something very specific in power systems. It's the capability of a system to provide power adequate to meet demand. The way your lights and electric heating stayed on during the cold snap? That means our wind based system was reliable. Now, if we'd expected the wind to produce a large number of MW during the cold snap and it didn't, leading to a shortfall in power generated - then your statement would have been fair.

    Also, that's not irony. Irony means something quite specific as well. ;)


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  • #7
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    L wrote: »
    That means our wind based system was reliable.

    If the turbines are not producing electricity and there is no form of power storage related directly to them, then based on the cold snap they cannot be considered reliable! The old reliables are the reliable part of the system.


  • #8
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    L wrote: »
    It's the capability of a system to provide power adequate to meet demand. The way your lights and electric heating stayed on during the cold snap?

    Also, that's not irony. Irony means something quite specific as well. ;)

    L took your advice

    From here 03.10.11 Winter Outlook 2011-2012
    http://www.eirgrid.com/aboutus/latestnews/

    The installed capacity of conventional, dispatchable generation in Ireland will be 6,792 MW for the winter 2011/2012,

    Average Installed Wind Capacity Winter 2010/2011 - 1,407MW.

    Average Wind Contribution at Peak Demand 2010/2011 - 354MW (25.2% of Installed Wind Capacity)

    Minimum Wind Output at Peak Demand 2010/2011 - 13MW (1% of Installed Wind Capacity)

    During the 2010/2011 winter period, the peak demand for electricity in Ireland was 5,090 MW.

    For the 2011/2012 winter, it is forecasted that the All-Island Peak Demand will be 6,780 MW.

    So:

    Conventional generation 6,792MW (100%) Wind Maximum Capacity 1,407MW (21%)
    Conventional generation 6,792MW (100%) Wind Average Contribution 354MW (5%)
    Conventional generation 6,792MW (100%) Wind Minimum Output 13MW (0.002%)

    Not sure where you are getting your figures, please link.

    Conventional generation 6,792MW (100%) forecasted All-Island Peak Demand 6,780 MW (100%)
    Oh oh!!!


  • #9
    Emory Ashy Violist
    Posts: 0 ✭ Emory Ashy Violist


    Oldtree wrote: »
    If the turbines are not producing electricity and there is no form of power storage related directly to them, then based on the cold snap they cannot be considered reliable! The old reliables are the reliable part of the system.

    The point of pumped storage, is that they store electricity in the form of water pumped into a high lake, tank or whatever using "spare" wind (or from anything in reality) generated electricity and when it isn't windy the stored water can be used to generate electricity.

    Of course, a prolonged period of still weather is going to result in "flat batteries", that would be true of any system.


  • #10
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    Turlough hill can produce 292MW at peak for about 6 hours, that it on pumped hydro at the moment, so whats your point?

    Conventional generation 6,792MW (100%) pumped hydro 292MW (4% for 6 hours)


    Untrue for "any system" Flat batteries dont exist in a convention system unless the plant is completely shut down!


  • #11
    L
    Registered Users Posts: 655 ✭✭✭L


    Oldtree wrote: »
    If the turbines are not producing electricity and there is no form of power storage related directly to them, then based on the cold snap they cannot be considered reliable! The old reliables are the reliable part of the system.

    ... that's pretty much straight out wrong. I know what you're trying to get across but it's based on a huge misapprehension.

    You don't care if wind doesn't blow all the time so long as you can cover for when it doesn't produce power somehow. As long as having wind power at all reduces the cost of electricity (without leaving us short on electricity randomly) longterm, it's a good thing. Think of it as swings and roundabouts.

    Now, the complication here is that it's difficult to get cheap generation online quickly. As a rough rule of thumb (and a massive oversimplification), the quicker generation is to get online, the more expensive it is to generate from.

    In other words, it's not so much whether wind blows or doesn't blow that causes problems (IIRC, wind power produces roughly 30 odd percent of the nameplate capacity when averaged over a year), it's whether or not it's predictable that matters.


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  • #12
    L
    Registered Users Posts: 655 ✭✭✭L


    Oldtree wrote: »
    Not sure where you are getting your figures, please link.

    Eirgrid as I told you. There's a nice cleaned up summary version here or you can look at their own raw information here.

    So you know, power systems are what I do for a living. If I say something, you can rest assured I'm not pulling it out of my ass (though I'll note I'm not actually infallible). :)


  • #13
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    I had guessed you were in the industry which is why I pulled the nice clean facts from Eirgrid's most recent news!

    If it dosnt blow when you need it and you dont have storage for the spare then its useless.

    Wind generated electricity is more expensive thus the subsidies we have to pay.

    I agree that the idea of renewables is a good thing but as usual when big business gets in it is no longer for the common good. It is not a blanket right or wrong but I firmly believe in the right system right place as outlined in previous threads. I would be happy to see small turbines in a multitude of locations, with owners given a decent rate by eirgrid, medium sized biomass plants all over the place, pumped hydro storage in appropiate places!


  • #14
    L
    Registered Users Posts: 655 ✭✭✭L


    Oldtree wrote: »
    If it dosnt blow when you need it and you dont have storage for the spare then its useless.

    Not quite the way it really works. It's a bit tough to explain but:

    Generally what happens is conventional generation is displaced by wind power to save fuel. You want to avoid storage whenever possible because it basically leaks energy. If you can, you use wind power immediately by displacing regular conventional generation so you end up with a nice pile of spare fuel you can use later without paying the cut storage losses would incur (or alternatively soak up the excess energy in some other way that doesn't involve retrieving it from storage).

    That's largely why I don't like it when people refer to storage and renewable energy as a package deal.
    Oldtree wrote: »
    Wind generated electricity is more expensive thus the subsidies we have to pay.

    Well, not necessarily. This is a bit outside my area but if IIRC it's that wind farms have very long payback periods (off the top of my head 20 years before any profit is made comes to mind?). They don't make much sense for capitalists to invest in unless they're frontloaded a little with subsidies. The benefits are still pretty solid for the average person on the street though - especially in the longterm.
    Oldtree wrote: »
    I firmly believe in the right system right place as outlined in previous threads. I would be happy to see small turbines in a multitude of locations, with owners given a decent rate by eirgrid, medium sized biomass plants all over the place, pumped hydro storage in appropriate places!

    Oh aye, I think mainly we just disagree on what the right system is. :P


  • #15
    djpbarry
    Registered Users Posts: 13,104 ✭✭✭✭djpbarry


    Oldtree wrote: »
    Wind generated electricity is more expensive...
    I would love to know the origin of this myth. Please provide figures showing that wind-generated electricity is more expensive than other forms of generation.


  • #16
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    Please provide info that it isn't. We are the ones paying the subsidies to keep it ticking over on top ot the regular forms of generation!


  • #17
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    A recent document to support your thesis is the following:

    http://www.seai.ie/Publications/Statistics_Publications/Energy_Modelling_Group/Impact_of_Wind_Generation_on_Wholesale_Elec_Costs/Impact_of_Wind_Generation_on_Wholesale_Electricity_Costs_in_2011.pdf

    where the conclusions are:

    The objective of this exercise was to quantify the likely impact of the wind generation that will be on the system in 2011 on the wholesale cost of electricity. The analysis showed that wind generation lowers wholesale prices by €74 million, which almost exactly offsets the costs of the Public Service Obligation (PSO) levy and other costs assosiated with the generation of wind energy. The study clearly demonstrates that wind energy is not contributing to higher wholesale electricty prices on the Irish electricity system. In light of recent debates on the cost of wind, it is useful to have this information modelled using the best objective assumptions available today and the appropriate assessment tools. Further benefits would arise from performing an expanded exercise to look at the cost impact of wind and other renewable
    technologies in the 2020 time frame.

    But their conclusions, conveniently, are arrived at on the following assumptions, exclusions and restrictions of the study:

    The basis for the modelling exercise is the 2011 all-island electricity system. As such the scope of this study does not include an examination of the likely capital investment costs involved in expanding the generation portfolio / transmission network to support a secure future electricity system, or the fixed costs incurred by generators.

    Seems to me ther are a few costs missing in their calculations, with the real elephant in the room being the lack of recognition of the ongoing maintainance costs of wind (which I have read can be as high as 5%), as against the popular cry of "once established its free electricity".


  • #18
    L
    Registered Users Posts: 655 ✭✭✭L


    As a small point of information, the AIGS is a Unit Commitment study so it neglects costs not directly relating to generation or demand to keep the model runnable. I haven't looked at the study you linked but I'd guess it's the same - maintenance costs and capital costs are on the person who owns the generator, not on the state.

    You'll never see a study with everything included because it can't be simulated and it certainly can't be debugged. That said, there are other studies that look at the capital investment/maintenance side of things. :)


  • #19
    djpbarry
    Registered Users Posts: 13,104 ✭✭✭✭djpbarry


    Oldtree wrote: »
    Seems to me ther are a few costs missing in their calculations, with the real elephant in the room being the lack of recognition of the ongoing maintainance costs of wind (which I have read can be as high as 5%), as against the popular cry of "once established its free electricity".
    SEAI estimate the cost of a 5MW wind farm as €7-10 milion. This figure includes “the feasibility studies, EIS and planning application, civil and electrical engineering works, grid connection costs, plus all operating, maintenance and decommissioning costs.”
    http://www.seai.ie/Renewables/Wind_Energy/Wind_Farm_Development/Financing_wind_farms

    Ireland has about 1,400 MW of installed wind capacity, so let’s put a cost of €2 – 2.8 billion on that. Let’s give a wind farm a conservative lifetime of 20 years and a conservative average capacity factor of 25%. That gives an output of about 61 TWh over the lifetime of the entire wind system. That gives a cost per kWh in the approximate range of €0.03 – 0.05, which is pretty damn cheap.


  • #20
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    djpbarry wrote: »
    SEAI estimate the cost of a 5MW wind farm as €7-10 milion. This figure includes “the feasibility studies, EIS and planning application, civil and electrical engineering works, grid connection costs, plus all operating, maintenance and decommissioning costs.”
    http://www.seai.ie/Renewables/Wind_Energy/Wind_Farm_Development/Financing_wind_farms

    Ireland has about 1,400 MW of installed wind capacity, so let’s put a cost of €2 – 2.8 billion on that. Let’s give a wind farm a conservative lifetime of 20 years and a conservative average capacity factor of 25%. That gives an output of about 61 TWh over the lifetime of the entire wind system. That gives a cost per kWh in the approximate range of €0.03 – 0.05, which is pretty damn cheap.

    Yes, it is. If only it were reliable then it would be perfect.


  • #21
    L
    Registered Users Posts: 655 ✭✭✭L


    easychair wrote: »
    Yes, it is. If only it were reliable then it would be perfect.

    *twitch*

    https://www.youtube.com/watch?v=G2y8Sx4B2Sk



    For the sake of my head use a different word please.


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  • #22
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    L wrote: »
    *twitch*

    For the sake of my head use a different word please.

    It's important we use words which are accurate. There seem to be those who think wind power is constant, and is reliable. It would be WONDERFUL if it was, but it's not and we do them a disservice if we don't point out the facts.


  • #23
    Emory Ashy Violist
    Posts: 0 ✭ Emory Ashy Violist


    easychair wrote: »
    It's important we use words which are accurate. There seem to be those who think wind power is constant, and is reliable. It would be WONDERFUL if it was, but it's not and we do them a disservice if we don't point out the facts.

    No one is claiming that wind is reliable in the sense that it will always provide a reliable supply of electricity, the whole concept of pumped storage in this context is to expand the "window of supply" by generating "wind stored" electricity when the wind dies down.


  • #24
    L
    Registered Users Posts: 655 ✭✭✭L


    easychair wrote: »
    It's important we use words which are accurate. There seem to be those who think wind power is constant, and is reliable. It would be WONDERFUL if it was, but it's not and we do them a disservice if we don't point out the facts.

    Yes, but as I was pointing out earlier 'reliable' is a word that means something quite different in this conversation from what you're using it as.

    Wind power is not persistent. Wind power is intermittent. Use those terms. Don't keep using 'reliable' or 'unreliable' please!


  • #25
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    easychair wrote: »
    As was said, wind power is seductive, and a wonderful thing, but it's not reliable
    djpbarry wrote: »
    Yes it is – reliability and intermittency are not the same thing.
    http://www.boards.ie/vbulletin/showpost.php?p=75363585&postcount=115

    Emory Ashy Violist wrote: »
    No one is claiming that wind is reliable in the sense that it will always provide a reliable supply of electricity,

    It's hard to speculate what other way it could be thought reliable. I was told that I was wrong to claim the wind was unreliable, and I was responding to that poster who seems unaware of the definition of the word.

    He actually said "Yes it is" correcting my use of the word "reliable" implying that the wind is reliable, which by any definition of the word ( I chose the OED) it is not.


  • #26
    L
    Registered Users Posts: 655 ✭✭✭L


    easychair wrote: »
    He actually said "Yes it is" correcting my use of the word "reliable" implying that the wind is reliable, which by any definition of the word ( I chose the OED) it is not.

    Seriously, that's ridiculous. If you're going to talk about a technical subject, accept the lexicon it uses. It's there to prevent these stupid 'talking about different things' conversations.

    Wind power is not unreliable. Unforecasted Wind power is unreliable. Wind power is intermittent.


  • #27
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    I get it! I get It! ;)
    Wind turbines are reliable, its the wind that isn't! :D


  • #28
    L
    Registered Users Posts: 655 ✭✭✭L


    Oldtree wrote: »
    I get it! I get It! ;)
    Wind turbines are reliable, its the wind that isn't! :D

    Hah. Very clever :P


  • #29
    Oldtree
    Registered Users Posts: 8,104 ✭✭✭Oldtree


    The government is aiming for 40% renewable energy by 2020. What thereafter 60% 70% 100% in what time frame? While I appreciate that the renewables displace conventional production if the object is to move away from conventional production, does that not mean that using them as backup will disappear in the future as no more conventional plants will be built implying a huge need for a massive backup batteries or pumped hydro or some other such means to be self sustainable.


  • #30
    easychair
    Closed Accounts Posts: 905 ✭✭✭easychair


    L wrote: »
    Seriously, that's ridiculous. If you're going to talk about a technical subject, accept the lexicon it uses. It's there to prevent these stupid 'talking about different things' conversations.

    Wind power is not unreliable. Unforecasted Wind power is unreliable. Wind power is intermittent.

    I speak English and have no idea where to find the lexicon to which you refer. In any case, just because there may be a lexicon somewhere to which we should all refer before posting here, that still doesn't change the definition of words used in normal English.

    This forum is not reserved exclusively for those who talk in words found in your lexicon, it's for anyone who has an interest in the subject. If you are unable to understand, or accept, that wind power is not reliable, as defined by the OED, that's fine by me. If you are not able to understand that being intermittent means that it is unreliable, that's also fine.

    Conventional power stations, such as oil and gas and peat and nuclear are reliable precisely because they are not intermittent. Which is why they are still needed.


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  • #31
    pljudge321
    Registered Users Posts: 1,129 ✭✭✭pljudge321


    easychair wrote: »
    I speak English and have no idea where to find the lexicon to which you refer. In any case, just because there may be a lexicon somewhere to which we should all refer before posting here, that still doesn't change the definition of words used in normal English.

    If you are really interested acquire this and read.

    For anyone looking for handing figures for where the electricity is coming from you can get them here. Its a bit handier than looking at EirGrid's website.


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