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On-grid domestic battery storage

edited 30 November -1 at 1:00AM in Green & Ethical MoneySaving
1.8K replies 198.2K views
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  • Martyn1981Martyn1981 Forumite
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    zeupater wrote: »
    Hi

    Agree, I know a couple of people (and am aware of a number more from various sources!), who have been disappointed by their battery performance relative to supplier claims and have eventually been able to return their product for a full refund (took some time, but they have done it!), which supports a conclusion that many justification models are seriously flawed ...

    I would rather expend my effort helping both suppliers & consumers understand the issues involved in employing erroneous logic at this early stage, than see seriously negative newspaper headlines concerning home storage in a few years time ...

    In reality, I'd rather that the relevant industry associations, Ofgem, FCA etc sat down and agreed to commission a standardised assessment process & basic algorithm to be employed by all suppliers in correspondence with potential customers, particularly so at quotation stage, but that would either need to be driven by the industry now, or imposed by regulation later !

    HTH
    Z

    Yep. To all that.

    I'm more than happy to agree that cycles should exceed 6,000 going forward, and batts should last much more than 10yrs going forward, but I'm not going to suggest to anyone else that they trust me and invest £5k+ based on my beliefs. Not till we have more to go on.

    For instance I used to say that folk should expect an inverter to fail during the first 10yrs, and cost ~£1k. Now I think that's less likely, will cost less, and can be insured against via extended warranties.

    As explained (too many times (sorry)) I think for safety's sake we should omit inflation and cost of capital, so I thought I'd see what that would give us:

    I'm going to go with the £6k and 10kWh (useable (I assume)) suggested, and the 2% capacity loss pa.

    I'm also going to use E7 for one third of the cycles, and assume 32 days pa when no cycling occurs - partly to represent faults with the batt, faults with the PV, days in the sunnier months when weather is too poor to charge, and holidays etc & partly to fudge round numbers of 30yrs and 10,000 cycles.

    In the first decade we get 333 days x 9kWh (90% capacity average) = 29,970kWh

    In the second decade we get 333 days x 7kWh (70% capacity average) = 23,310kWh

    In the third decade we get 333 days x 5kWh (50% capacity average) = 16,650kWh

    So, that's a total of 69,930kWh's.

    2/3rds or 46,620kWh's save us 15p/kWh = £6,993
    1/3rd or 23,310kWh's save us 6.6p/kWh* = £1,538

    Total = £8,531 and a saving of £2.5k over 30yrs

    [*6.6p is the saving based on E7 at 7.5p, day rate at 15p, and batt efficiency losses meaning that 1.12kWh of E7 is needed for 1kWh of output.

    However, is it worth bothering with E7, I doubt it at these battery costs since we have a batt cost of £6k/69,930kWh's = 8.58p/kWh which when added to the E7 purchase cost of 8.4p = 17p/kWh exceeding the saving of 15p/kWh day rate.

    Better perhaps to protect the capacity of the batts.]


    Would I do that - no.

    Would I do it if I was certain that it would last 30yrs and 10k cycles - no.

    Would I do it if I was certain that it would last 30yrs and 10k cycles and costs won't fall significantly over the next 5-10yrs - yes.

    Would I recommend that other folk invest £6k to make £2.5k over 30yrs ......... nope!

    Would it work for me, not today, the battery draw down in year 1 is 3,330kWh's and I import about 1,600-1,700kWh's pa, but in the future as I've mentioned on thread my demand may go up further thanks to an EV, and this will hopefully coincide with falling storage costs.

    Lastly do I like the look of what is being offered by this company - yes. It's pretty much everything I would hope for, and I believe a reasonable price compared to elsewhere. Unfortunately the state (price) of the technology is too high today (no ones fault), and I fundamentally object to the use of inflation, especially high inflation rates over long time periods, to make something work. I'm funny like that!
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • edited 8 November 2018 at 8:58AM
    Exiled_TykeExiled_Tyke Forumite
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    edited 8 November 2018 at 8:58AM
    Agree to all of that too. And my (I hope) final thought on this matter, is that if we need electricity prices to rise so much to make batteries financially viable, then surely the best thing to do is wait for the price increases to take hold (rather than speculate) and then invest?
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    Install 2: Sept 19, 600W SSE
    Solax 6.3kW battery
  • zeupaterzeupater Forumite
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    Agree to all of that too. And my (I hope) final thought on this matter, is that if need electricity prices to rise so much to make batteries financially viable, then surely the best thing to do is wait for the price increases to take hold (rather than speculate) and then invest?
    ... :rotfl::rotfl:... now that is what I would certainly classify as "thinking outside the box!" ... makes quite some sense though! .. ;):T

    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    B)
  • pile-o-stonepile-o-stone Forumite
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    Martyn1981 wrote: »
    I'm sorry but there is simply too much money involved to sit idly by and accept/tolerate claims of ROI on overly high inflationary uplifts.

    Which is fine, but this aim was achieved pages ago. Who is now reading apart from the four people arguing, who already have entrenched positions? Maybe it's just me, but when I see the multiple quotes where the discussion is dissected to the point where people are arguing about the argument, I switch off and just scroll past it all.

    I did read the first posts and concluded that while battery storage costs seem to be moving in the right direction, they're not there yet, except perhaps for someone with a large array who is at work all day, but you'd have to ask why they got solar in the first place, except perhaps to earn money from the Fits.
    5.18 kWp PV systems (3.68 E/W & 1.5 E).
    Solar iBoost+ to two immersion heaters on 300L thermal store.
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  • orreryorrery Forumite
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    Agree to all of that too. And my (I hope) final thought on this matter, is that if we need electricity prices to rise so much to make batteries financially viable, then surely the best thing to do is wait for the price increases to take hold (rather than speculate) and then invest?


    The trend is for generating costs to fall as more renewables are introduced, but I suspect that the trend will be for retail prices to rise in the short to medium term as the roll-out of renewables is effectively limited by the government, which seems unconvinced (or, more likely, unwilling).


    I suspect that the domestic battery roll-out will be driven by utility companies wanting to manage their own power and offering batteries for discounted prices, which is unlikely to benefit independent suppliers.
    4kWp, Panels: 16 Hyundai HIS250MG, Inverter: SMA Sunny Boy 4000TL, SolarImmersion
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  • edited 8 November 2018 at 12:58PM
    Martyn1981Martyn1981 Forumite
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    edited 8 November 2018 at 12:58PM
    I did read the first posts and concluded that while battery storage costs seem to be moving in the right direction, they're not there yet, except perhaps for someone with a large array who is at work all day, but you'd have to ask why they got solar in the first place, except perhaps to earn money from the Fits.

    Yep, not yet worth it, so the issue then became the manipulation of inflationary uplifts to make it viable, which many might find believable, so should the continued support of that claim go unopposed?

    Basically should we be worn down by the repeated postings of a one sided and misleading argument (appeasement), or should we stand up and challenge it each time.

    Remember this site is a money saving site set up by a person who always challenged deals and the underlying economics, especially if they might possibly be misleading.

    Without people willing to oppose some of the more extreme claims we would still have 'The Green Man' on here posting pictures of pigs with their snouts in the trough in response to you (and me and others) having PV and FiTs, and that just wouldn't be fair.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Apologies if this has already been posted, just news from a few weeks ago as I'm keen to see what Duracell has to offer.

    No prices or specs yet.

    https://www.solarpowerportal.co.uk/news/duracell_to_launch_ai_enabled_home_battery_system_next_month_for_uk_market
    3.5kWp 12-panel PV system, south facing.
  • pile-o-stonepile-o-stone Forumite
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    Martyn1981 wrote: »
    Yep, not yet worth it, so the issue then became the manipulation of inflationary uplifts to make it viable, which many might find believable, so should the continued support of that claim go unopposed?

    Basically should we be worn down by the repeated postings of a one sided and misleading argument (appeasement), or should we stand up and challenge it each time.

    Remember this site is a money saving site set up by a person who always challenged deals and the underlying economics, especially if they might possibly be misleading.

    Without people willing to oppose some of the more extreme claims we would still have 'The Green Man' on here posting pictures of pigs with their snouts in the trough in response to you (and me and others) having PV and FiTs, and that just wouldn't be fair.

    I agree that we should set things right when incorrect claims have been made. It just went on and on and the argument became about the argument (he said, she said), which helps no one and people just stop reading.

    I only come onto MSE because of you Mart, (You mentioned this site on Navitron) so please don't take my comments as deep criticism. I am subscribed to this thread and the solar & green energy ones as they are a cracking resource to keep abreast of the news. When they are instead full of an argument it swamps everything else. I do realise though how you have to challenge inaccuracy when it occurs.
    5.18 kWp PV systems (3.68 E/W & 1.5 E).
    Solar iBoost+ to two immersion heaters on 300L thermal store.
    Vegan household with 100% composted food waste
    Mini orchard planted and vegetable allotment created.
  • edited 9 November 2018 at 7:40PM
    zeupaterzeupater Forumite
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    edited 9 November 2018 at 7:40PM
    ... they are instead full of an argument it swamps everything else. I do realise though how you have to challenge inaccuracy when it occurs.
    Hi

    That's it in a nutshell ... it's unfortunate that the approach needs to be particularly forensic & technically robust when challenging potential inaccuracy in order to see where reality lies - particularly so when vested interests are involved ...

    Hopefully anyone interested in buying a battery that comes across this thread will attempt to take more time to follow the logic applied in that exchange of views than the average reader, but then again, maybe every reader will now better understand the level of complexity in forecasting & justification of such products and be reminded to be slightly more cautious whenever claims are made in the future .... if so, despite the hours of thinking & typing expended, I'd consider it as job done!

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    B)
  • edited 9 November 2018 at 3:40PM
    Martyn1981Martyn1981 Forumite
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    edited 9 November 2018 at 3:40PM
    I agree that we should set things right when incorrect claims have been made. It just went on and on and the argument became about the argument (he said, she said), which helps no one and people just stop reading.

    Yes it did seem silly, my problem was that acceptance of the high inflationary rate makes (in my opinion) the batt viable today*. And then all hell breaks lose ........ So as I don't believe in that inflationary figure, and think(?) I justified that position based on NAO price projections, I had to keep on keeping on.

    *I also believe that the number of cycles and life expectancy of these batts will be much higher if DoD is kept to 90% or less, though as explained I can't count on that yet as the products are relatively new so whilst it should be fine long term, we don't yet know if any individual products will have problems.

    Two other issues which i think Z and I did to death was the reliance on E7. It sounds like a good idea, and as batt prices fall the arbitrage potential should become viable, but I've really no idea if E7 will continue in its current form. It was created largely for the nuclear industry, and that industry is now struggling. Increased demand from heat pumps and EV's might remove the differential between high demand and low nightime demand. Wind generation might make E7 more viable ..... I really don't know.

    One other issue touched upon was the cost increase in supply (poles and wires etc) from increased demand, but that is really obvious until we take a step back and think for a second - the UK HV and LV networks are built to cope with peak demand, if we increase total demand but avoid increasing the peak, then investment might not be as high as we would at first think. One way of levelling out demand is ..... wait for it ...... drum roll ...... storage. So we go in a circle and find that storage might reduce the amount of investment needed, but the investment is needed to justify the storage (at this point in time)!

    I'm also not convinced that standing charges pay for all such costs since they vary so much across companies and offerings, so the extra money needed by the HV or LV operators might simply come from revenues on handling greater total volumes of leccy.

    Is this confusing, yes. Am I confused, yes. Will there definitely be 8.4% compounded inflation on leccy for 10-20yrs ...... nope.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
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