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    • CommentAuthorowlman
    • CommentTimeAug 28th 2019
     
    Has anyone had any installed, there seem to be some reasonable deals available?
    • CommentAuthortony
    • CommentTimeAug 28th 2019
     
    I hope not unless off grid

    They are inherently inefficient causing increased energy demand overall
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 29th 2019 edited
     
    @owlman: please see my writeup below with some analysis. The full grid-connected storage dataset is available at just over a year: tell me if you have any trouble with it.

    Note that with this experiment I am trying to reduce grid flows efficiently rather than eliminate them, and indeed the round-trip losses saved over the DNO's wires probably in themseleves roughly cover any round-trip losses through the storage.

    http://www.earth.org.uk/Enphase-AC-Battery-REVIEW.html

    http://www.earth.org.uk/electricity-storage-whole-household-2018.html

    I have a much longer running off-grid storage system too.

    Rgds

    Damon
    • CommentAuthorGreenPaddy
    • CommentTimeAug 29th 2019 edited
     
    DamonHD, really interesting piece of work. Great when people really get into the nitty gritty of these systems, as the devil really is in the detail (not that I'm sure I fully understood ALL the details).

    I've always suspected that the very simple "sales" assumptions of best case power savings, are based on operating scenarios that are quite hard to manage. eg. holding off the battery re-charge from grid, until the PV starts to go into export, so that you're minimising grid re-charge. Many of the same issues with solar thermal and say a gas boiler, in that you want to hold off re-heat until you know there's no chance of solar doing the heating.

    Also liked your very honest initial statement about the system never paying back (at least I think that's what I understood?). As long as people know why they are installing the unit, not to save them heaps of money, but for other reasons, that's great.
    • CommentAuthortony
    • CommentTimeAug 29th 2019
     
    Do the calculations include servicing, testing and replacement costs?
    • CommentAuthorowlman
    • CommentTimeAug 29th 2019
     
    Thanks Damon.
    I think the running costs you indicate tony seem to be fairly negligible.
    Most batteries come with a 5 year warranty, extendable to 10, or more in the odd case. The connection seems to be not much more than three wires in the case of fully integrated ones, and Companies that just do the batteries, and not the peripherals, only seem to require an inverter interface between the battery pack and the mains so not a lot to go wrong.
    Capacity is the big question and how much you need to power the home during dark hours, midwinter, before a solar re-charge the following day.
    I don't think the battery prices have quite bottomed out yet, but one to watch, and of course, you've still got to pay an electricity supply company a standing charge to remain connected.
    •  
      CommentAuthordjh
    • CommentTimeAug 29th 2019
     
    Posted By: owlmanyou've still got to pay an electricity supply company a standing charge to remain connected.

    You don't actually. There are still some zero-standing charge tariffs available, of which the best known is from Ebico.
    •  
      CommentAuthordjh
    • CommentTimeAug 29th 2019
     
    Posted By: owlmanI think the running costs you indicate tony seem to be fairly negligible.
    Most batteries come with a 5 year warranty, extendable to 10, or more in the odd case.

    Well, that would seem to indicate the running costs must be at least 1/10th of the purchase price every year. Depreciation is a real cost.
    • CommentAuthorowlman
    • CommentTimeAug 30th 2019
     
    Posted By: djh
    Posted By: owlmanyou've still got to pay an electricity supply company a standing charge to remain connected.

    You don't actually. There are still some zero-standing charge tariffs available, of which the best known is from Ebico.


    True Dave but at nearly 25p per unit they get the standing charge from you in another way. I'm currently paying 13.22 per unit and 11.897 per day.
    • CommentAuthorborpin
    • CommentTimeAug 30th 2019
     
    Posted By: tonyThey are inherently inefficient causing increased energy demand overall
    Yes and no. There is quite a bit right now about the Octopus Agile tariff. One of the guys on the OEM forum has put a website together to allow some analysis (I'll post link in a moment).

    One of the key issues is the variability of demand. If you can smooth that you'd need less generation overall. One way to reduce that variability is via batteries - charge when there is an excess of generation, discharge at peak.

    The Octopus Agile tariff actually makes that far more viable.
    • CommentAuthorborpin
    • CommentTimeAug 30th 2019
     
    • CommentAuthorGarethC
    • CommentTimeAug 30th 2019
     
    https://pushevs.com/2019/08/05/best-battery-cells-for-diy-projects/

    This article talks about batteries for €190 per kWh, which seems really good value, am I right? Tentatively thinking of building my own system.
    • CommentAuthorowlman
    • CommentTimeAug 30th 2019
     
    In a similar vein Brian one company is promoting something called "grid share".
    I'm assuming they once they have a critical mass of installs, all linked, then they can with permission deplete each battery by a small amount, in effect creating a storage power station, which with smart technology is monitored and the householder gets a cut of the profit.
    I seem to remember reading somewhere that the system had been trialed in Japan.
    I have no idea if it's feasible or not.
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 30th 2019
     
    @owlman at least Moxia (and probably also Powervault with EDF) does something similar right now, ie you can opt to participate in energy sharing back to the grid in return for a lower price or an annual fee, etc...

    This market will grow, since reducing grid flows can allow reinforcement activities and admit more renewables for example.

    Rgds

    Damon
  1.  
    Hi Damon, one year ago we discussed:

    "Can you correlate the time of day of consumption with your grid intensity report?

    "IE work out:
    A) the CO2 that could have been displaced if you had exported at time of generation during the day
    B) the CO2 that was avoided when you drew battery instead of importing at night

    "Is the difference +ve or -ve, did you actually save some CO2 overall?"


    Did you get chance to work this out?
    Cheers Will

    http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15801&page=2
    •  
      CommentAuthorDamonHD
    • CommentTimeAug 31st 2019
     
    @WillInAberdeen not yet, though I do now have a full year of detailed (5min) consumption data c/o the Enphase, which is a start.

    Rgds

    Damon

    PS. Not all home batteries are for electricity: don't forget Sunamp's heat battery, which can be charged with resistance heating, heat pump, or even solar thermal, AFAIK.
    • CommentAuthorborpin
    • CommentTimeSep 8th 2019 edited
     
    Final thought, I read through the initial report on the power outage last month. One of the interesting aspects was the impact of losing "embedded generation" (c. 500MW) due to Loss of Mains Protection when the initial lightening strike caused the sub station to trip. It was this loss that took the cumulative loss above the reserve and ultimately triggered the LFDD.

    Yes it was a little more complex than that, but I'm not sure the planning assumptions had actually taken this change in the infrastructure into account (from what I have read).

    Bit OT, but the move to embedded generation does have other consequences.

    https://www.ofgem.gov.uk/system/files/docs/2019/08/incident_report_lfdd_-_summary_-_final.pdf

    BTW I love the fact this has 'Highly Confidential' as a privacy marking.

    [edit]
    And it was really interesting that the problems on the trains were because a particular class of rolling stock reacted badly to the dodgy supply frequency *not* because of a loss of power to Network Rail.
    •  
      CommentAuthordjh
    • CommentTimeSep 8th 2019
     
    Thanks for the link, Brian. I guess on 19 Aug it perhaps was Highly Confidential!? I see the finalreport was due to be published two days ago, maybe that is still confidential?

    The report doesn't explain either of the two main generator failures or the rail failures in any detail at all. I don't know whether that was out of scope or just too soon to have the information. I hope the analysis is eventually published.
    • CommentAuthorFlubba
    • CommentTimeSep 8th 2019
     
    Might be better replying to this elsewhere as it's not really battery related.

    I'd be interested to know more about the generation failures particularly Hornsea Windfarm since by default that is becoming a bigger slice of the pie.

    Little Barford CCGT I believe was steam condition issues which forced the control systems to trip the steam turbine offline and then because there is nowhere for the steam generated by the HRSG to go the gas turbines were tripped out as well.

    One theory online is that the surge generated by the lightning strike caused the steam turbine to temporarily overspeed causing protection to throttle which then 'upset' the steam conditions within the turbine. Essentially an overreaction or over-sensitivity of the control systems. Personally I don't buy the lightning story considering the thousands of times each year the grid is hit by lightning without issue.

    The rail failures and chaos is a bit clearer, borpin has it correct with regards to no traction power was actually lost but as mentioned by borpin the 25kV overheads are AC. The Class 700 and 717 are nice modern trains with solid state electronics, full health and usage monitoring connected to the wider world. Unfortunately with a deviation in frequency the train defaults into a safe state as it doesn't like odd things happening with it's power supply. The difficulty of restarting the trains comes down to the joy and reality of modern maintenance and supply contracts whereby the train operating companies don't own the trains and can't do much of the maintenance themselves. Further to this you will have discrepancies in which drivers know their way around the computerised systems to get things restored, which drivers are native to the TOC, where did the train fail e.g. within a neutral section or overlap etc.

    Much of the disruption however was caused by the loss of infeed to at least 2 signalling substations that supply power to trackside signalling equipment, normally like any other important system this should seamlessly switch over to battery and diesel. Unfortunately the aim of the game within government is to save money therefore many sites now have diversity of supply from the 25kV overhead traction via a stepdown transformer, brilliant what could go wrong...

    Instead what happened is the signalling systems did what they are designed to and failed safe causing a 'red spread' which basically turns into a ripple across a route bringing trains to a stand. Naturally if you get a danger signal unexpectedly especially if it's put back in front of you the signaller in charge must be contacted and the signaller must contact each train within his area to confirm they have permission to proceed.

    This was fine when you had hundreds or thousands of signallers in signal boxes each with at most two dozen trains on his panel, you can process what is happening on your patch and contact drivers reasonably quickly. Now you can have one signaller controlling several dozen trains over hundreds of route miles with junctions and branch lines.

    Apologies if I de-railed the thread :shamed:
    • CommentAuthortony
    • CommentTimeSep 9th 2019
     
    Having derailed, I have to say that National Grid are extremely good at managing the grid and reckon that this will be a one off event. They practice on scenarios of multiple failures but the scale of loss on this and breakdown caught them with no resource. Batteries would not have helped
    • CommentAuthorborpin
    • CommentTimeSep 9th 2019 edited
     
    Posted By: FlubbaMuch of the disruption however was caused by the loss of infeed to at least 2 signalling substations that supply power to trackside signalling equipment, normally like any other important system this should seamlessly switch over to battery and diesel. Unfortunately the aim of the game within government is to save money therefore many sites now have diversity of supply from the 25kV overhead traction via a stepdown transformer, brilliant what could go wrong...
    From the report

    "Eight signal power supplies in principally rural locations suffered minor outages with minimal passenger impact.
    Network Rail are reviewing resilience at these locations;"

    Are you saying that the problems with the overhead lines translated to problems with the signalling supply because the signalling supply is taken from the overhead lines? If so, that is one of those clever omissions I feel.

    Posted By: FlubbaI'd be interested to know more about the generation failures particularly Hornsea Windfarm since by default that is becoming a bigger slice of the pie.
    What I took from the report was that the settings to the protection systems were too sensitive so dropped out when really they should not have done so.

    "Following the lighting strike Hornsea immediately de-loaded from 799MW to 62MW. Hornsea have confirmed that the equipment at Hornsea saw a system voltage fluctuation with unusual characteristics coincident with the lightning. The initial reaction from Hornsea’s systems was as expected in attempting to accommodate and address the system condition, but very shortly afterwards as the reaction expanded throughout the plant, the protective safety systems activated.

    Following an initial review, adjustments to the wind farm configuration, and fine tuning its controls for responding to abnormal events, the wind farm is now operating robustly to such millisecond events."

    Posted By: tonyBatteries would not have helped
    Actually my point is the opposite; as batteries and micro generation become more common, the impact of their loss could become more pronounced.

    Posted By: FlubbaApologies if I de-railed the thread :shamed:
    Groan.
    •  
      CommentAuthorfostertom
    • CommentTimeSep 9th 2019 edited
     
    https://www.positive.news/environment/new-solar-rig-to-drive-rail-line-directly-with-renewable-power/ implies that signalling etc is powered separately from traction.
    Wonder what 'directly connected' means in this case? Can't mean 'instead of mains connection'. Must include battery storage?
    •  
      CommentAuthorfostertom
    • CommentTimeSep 9th 2019
     
    I don't understand a word of https://twitter.com/ricfulop/status/1170527207657263104 via https://twitter.com/martynday but get a whiff that it's v significant. Can anyone translate?
    • CommentAuthorFlubba
    • CommentTimeSep 9th 2019
     
    Hello Borpin,

    Apologies I should have explained better, the signalling power substations or power supplies have a 'diversity of supply' therefore on failure of infeed from the Grid back in the dark ages the secondary supply would have been a back up diesel generator. Now however due to cost 'efficiencies' the secondary supply can be provided by the 25kV traction network.

    Better explanation here:- https://electrical.theiet.org/wiring-matters/issues/51/railway-systems/

    I'd hope most people can see the fallacy of having your backup power supply also be reliant on grid power but as you can imagine when British Rail and Railtrack first started making 'efficiency savings' removing thousands of diesel generators, fuel storage and associated maintenance overheads your saving a chunk of change. My father worked for the SSEB and later BR etc and vividly remembers the equipment being chopped up with a gas axe for scrapping.

    Some of the signal boxes on routes not yet electrified, especially up here in Scotland, still have their old diesel generators as my brother found out to his relief during the 'beast from the east'. Handy when management in Milton Keynes decide to replace your expensive and polluting Toyota Hilux with a Corsa Van...

    With regards to Windfarms and embedded generations dropping out I've been reading that it had a lot to do with 'Vector Shift' loss of mains protection, apparently the issues and concerns about vector shift have been known about for years and pointed to by National Grid to be one of their main concerns. It generally seems as if the slash dash grab-a-grant nature of embedded generation needs a serious rethink with greater control and visibility of embedded systems provided to National Grid.

    fostertom, It'll just mean it connected into one of the signalling substations so essentially just like any other grid connected solar system. As for that Twitter thread it seems as if it's the usual enthusiastic hyperbole based on the rubbishing it's been given in the replies.
    • CommentAuthorphiledge
    • CommentTimeSep 9th 2019
     
    Seems to me that all the headline issues were down to consumer issues rather than grid issues. For the rail issues the reports summary points the finger clearly at the inability of some trains to restart after power loss so I guess the train operator/manufacturer have some serious questions to answer.
    • CommentAuthorgravelld
    • CommentTimeSep 10th 2019
     
    Posted By: fostertomI don't understand a word ofhttps://twitter.com/ricfulop/status/1170527207657263104" rel="nofollow" >https://twitter.com/ricfulop/status/1170527207657263104viahttps://twitter.com/martynday" rel="nofollow" >https://twitter.com/martyndaybut get a whiff that it's v significant. Can anyone translate?
    I don't understand myself but this is the original article I read: https://electrek.co/2019/09/07/tesla-battery-cell-last-1-million-miles-robot-taxis/
    • CommentAuthorborpin
    • CommentTimeSep 10th 2019
     
    Final report https://www.ofgem.gov.uk/system/files/docs/2019/09/eso_technical_report_-_final.pdf

    @flubba Thansk for the explanation.

    I suppose the theory is that, with an all electric traction fleet, if the overhead power goes, nothing is moving to signal anyway!

    On embedded generation, they already had something which they are suggesting they need to accelerate.

    On the trains "The technical specification for the trains states that the trains will continue to operate with supply frequency drops down to 48.5Hz for short periods of time. All other GTR classes of train were unaffected." Siemens are looking into it!
  2.  
    back to batteries.
    I'm presuming they dont suit high loads like car charging or heatpumps because they would just suck too much out too quick on each cycle, would that be correct?

    Example , no one in all day , PV charges house battery , come home from work, charge EV via batteries (initially, then from grid) over night.
    • CommentAuthorphiledge
    • CommentTimeSep 11th 2019
     
    From a green perspective, I suspect that youd be better letting your PV help power society during the day and put a timer on your charger to charge in the dead of night when theres likely to be a surplus of power available. I think this what happens if you have a smart battery set up where the grid controls the charging.
  3.  
    Phil edge, I agree.
    My question was more , how the batteries handle the heavy loads like EV ie 3kW loads taking all the supply in 2-3 hours (10kWh battery say) every evening.
    I'm imagining it'll wear them out faster.
   
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