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  • FIRST POST
    • Martyn1981
    • By Martyn1981 5th Dec 16, 3:57 PM
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    Martyn1981
    On-grid domestic battery storage
    • #1
    • 5th Dec 16, 3:57 PM
    On-grid domestic battery storage 5th Dec 16 at 3:57 PM
    Hello!

    Right, as discussed elsewhere, battery storage for self generation (typically PV) is interesting (to some), and gathering momentum in the UK. So here's a thread to discuss it, and watch it develop.

    I've called it on-grid, as off-grid is so much more specialised. And domestic as commercial scale storage, or grid scale can be chatted about on the Green & Ethical energy issues thread.

    So, where are, well this article lists about 20 systems that are available or should be available soon:-

    Introducing CleanTechnica’s New Home Battery Overview Page

    Jumping straight in with personal opinions:-

    Economical - Not yet. Prices are falling fast, the range of products is expanding fast, and large numbers are being deployed in some countries, either because the price of leccy is high (Australia & Hawaii) or because subsidy schemes exist (Sweden & Germany).

    Where are we today. My needs are a 4kWh system. That's 4kWh of useable capacity, which would mean about 8kWh of lead acid (LA), or about 5kWh of lithium ion (Li-ion). My research has found batts in the high £2k and up range. I need the price to be nearer to £1.5k.

    The Tesla Powerwall II, installed is approx £6.5k, which works out at about £2.2k for 5kWh, but of course, it doesn't work quite like that, as smaller systems will cost proportionately more.

    Environmental - Tricky one this (to say the least). Until storage is needed, it's not environmental. Renewable energy (RE) generation currently displaces gas generation, which is a demand follower. Once gas generation is pushed down to zero (at times) we need storage, but we aren't there yet.

    However, to push gas generation down to zero, we need more RE, and to ensure it is viable/economic/profitable, we will need storage - chicken and egg situation.

    The advantage of storage to the environment, is to take peaks of RE and timeshift them to peaks in electricity demand. On a domestic level, this works quite well as PV generates during the day into the afternoon (or evening) depending on the month, so any stored leccy is available for the evening peak 5pm to 7pm.

    That's the background, and now here's a thread to discuss options, prices, economics, and watch things unfold. Enjoy.
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
Page 6
    • zeupater
    • By zeupater 22nd Apr 17, 1:12 PM
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    zeupater
    Just some general battery news / official launches, but no prices.

    Mercedes now selling into the UK, that should help create a market, competition etc etc.

    Mercedes-Benz Ready To Sell Residential Storage Batteries In UK

    and LG Chem launching in the US, which will hopefully create competition with Tesla, and stir up publicity, which again should help with markets, prices, progress etc.

    LG Chem Officially Launches Home Batteries In North America
    Originally posted by Martyn1981
    Hi

    Can't remember exactly where, but I came across a breakdown of prices for the Mercedes system at sometime within the last couple of weeks. It seems that the battery units are modular & stackable, requiring a floor-standing base or a wall bracket system - you also buy the plastic top with the Merc logo separately - at the time I was surprised how much these 'accessories' cost ... from memory the base was around £300 and the silver plastic logo cap well over £100, totally reinforcing the view that domestic storage is currently being considered as a generous cash-cow product sector for anyone entering the market ...

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • zeupater
    • By zeupater 22nd Apr 17, 1:16 PM
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    zeupater
    ... Just checked the history on another laptop's browser and found the source mentioned above if anyone's interested ..... ( http://www.windandsun.co.uk/products/Batteries/Lithium-Ion-Batteries/Mercedes-Benz-Energy-Storage-Home#.WPtHkaLau02 ) ...

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • Martyn1981
    • By Martyn1981 22nd Apr 17, 5:53 PM
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    Martyn1981
    ... Just checked the history on another laptop's browser and found the source mentioned above if anyone's interested ..... ( http://www.windandsun.co.uk/products/Batteries/Lithium-Ion-Batteries/Mercedes-Benz-Energy-Storage-Home#.WPtHkaLau02 ) ...

    HTH
    Z
    Originally posted by zeupater
    Cheers, I found that very interesting. Would like to know if the £137 + VAT 'lid' is optional, when they say required ..... bleeding hell.

    The battery packs seem really good, about the best in cycles, efficiency and price I've seen for small systems, though admittedly still lots of money, but £1,100 for 2.3kWh useable is good in comparison.

    Shame the extras and the VAT add up, but certainly one to watch.

    I assume from the tech sheets that it's a dumb system, because they list the inverters it's compatible with, but then so was the PWI, and things seem to move on fast, as the PWII DC model isn't being offered in Aus, just the AC model with in built inverter.
    Last edited by Martyn1981; 22-04-2017 at 5:59 PM.
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 26th Apr 17, 7:33 AM
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    Martyn1981
    ... Just checked the history on another laptop's browser and found the source mentioned above if anyone's interested ..... ( http://www.windandsun.co.uk/products/Batteries/Lithium-Ion-Batteries/Mercedes-Benz-Energy-Storage-Home#.WPtHkaLau02 ) ...

    HTH
    Z
    Originally posted by zeupater
    Hello again, a thought struck me this morning, this batt has a round trip efficiency of 97% (presumably in DC use), so that's not so bad for those on the older FiT rates. Though it would mean installing a compatible inverter, but perhaps as and when an inverter fails in the future. More options better than less.

    Anyways, just a thought.
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • gefnew
    • By gefnew 3rd May 17, 8:31 AM
    • 35 Posts
    • 45 Thanks
    gefnew
    Hi Al
    Here is a bit of a blog from greeningme,with quite a good breakdown of pv use and battery charging data and conclusions.
    Maybe worth a read.
    http://greening.me.uk/
    regards
    gefnew
    • Martyn1981
    • By Martyn1981 8th May 17, 9:50 PM
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    Martyn1981
    Ffu 10
    Looks like the best 6 months will give good storage and Immersun use:

    April numbers!

    Electricity imported - 85kWh! (150kWh in April 2016)
    Generated - 301kWh (exactly the same as April 2016)
    Battery discharge - 102.88kWh
    ImmerSUN diversion - 54kWh (51kWh in April 2016)

    So with decent generation, I've been able to get 100kWh out of the battery and make a big dent in consumption, whilst also then still sending about as much as last year into the ImmerSUN for free hot water!

    That's about £15 in avoided electricity in one month - something I hope to be able to see continue throughout the summer months. Nice to have broken the 100kWh/month figure
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 10th May 17, 9:11 AM
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    Martyn1981
    Battery storage gaining momentum, though I still think it's too expensive in the UK ...... but gotta start somewhere I suppose.

    Mercedes-Benz enlists Innasol to aid UK storage push

    Eaton to tackle home storage market with ‘an army’ of installers and support staff
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 10th May 17, 9:13 AM
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    Martyn1981
    Large growth in PV and storage on the demand side predicted (kinda obvious I suppose)

    Navigant: Distributed solar-plus-storage worth US$49 billion in less than 10 years
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • NigeWick
    • By NigeWick 10th May 17, 10:47 AM
    • 2,646 Posts
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    NigeWick
    Battery storage gaining momentum, though I still think it's too expensive in the UK ...... but gotta start somewhere I suppose.
    Originally posted by Martyn1981
    I was hoping that V2G would be arriving sooner than it looks as though it is going to as I'm getting an EV next month. Although still expensive, I think I will invest in battery storage as soon as I can scrape the cash together. This is on the understanding that people who can afford to be early adopters will bring price drop due to numbers sooner.
    The mind of the bigot is like the pupil of the eye; the more light you pour upon it, the more it will contract.
    Oliver Wendell Holmes
    • Martyn1981
    • By Martyn1981 17th May 17, 10:59 AM
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    Martyn1981
    Hiya Chopper, there are lots of battery systems, most much smaller than the PWII, and many modular so you cab add more later on.

    For example there's the Enphase systems which are only 1.2kWh and about 350W charge/discharge.

    So if the prices fall far enough for the smaller systems it might well be a good idea to buy then. I'm clearly quite passionate about batts and their future, but the time isn't right yet unless you generate and import a ton of leccy still, but we'll get there. Australia is leading the charge as they have great generation, but also very high import prices, so the industry is developing, but it's probably where PV was 5yrs ago, so patience is needed in the UK. Drat!

    All the best.
    Originally posted by Martyn1981
    OK Mart you can see that I am able to generate a lot of eleccy, but still appear to be consuming a lot also, say £30 a month, is this close to making a battery viable for me yet?
    Originally posted by rugbyleaguesmate
    Hiya. My thoughts.

    First off, my opinion, but I think prices will probably fall faster than savings will be earned for the next few years. So you are almost certainly going to be better off waiting. Also as costs fall, and hopefully life cycles or warranted cycles rise, then the cost of storing a kWh of leccy will also fall, which will improve your savings/returns.

    Next. My way of calculating my savings and battery size, and it's crucial to point out that this is for me, as I genuinely don't know the best way to calculate this, nor exactly how it will vary from PV'er to PV'er. So here's the link to our previous discussion:

    Hiya. To start
    Originally posted by Martyn1981
    So I think you need to do some number crunching, and I'm happy to help, in fact it should be interesting seeing the numbers from a different angle (higher import/export). Hopefully others will comment and assist so we start to get an idea how to do this.

    So, are you able to make a reasonable guess at each months import and export broken down to a daily amount, to see how much of a batt's capacity you need and so we can see what can be displaced? I think a 4 way breakdown might be enough (Winter Dec-Feb, Summer June-Aug, Spring/Autumn Mch-May & Sep-Nov).

    Can you supply import price, and I assume you get the 5p export rate, which might become a factor in the future. Savings will be import - cost of storage, or later on, import - (cost of storage + export rate).
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • rugbyleaguesmate
    • By rugbyleaguesmate 17th May 17, 10:16 PM
    • 227 Posts
    • 1,266 Thanks
    rugbyleaguesmate
    Hi Mart thank you my efforts are below, struggling with format.....

    Electricity Consumption
    Kw 16.072p rate per kw including standing charge
    Mid Nov Mid Feb 1108
    Mid Aug Mid Nov 777
    Mid Jun Mid Aug 802
    ex imp exp/d imp/d
    June 267
    July 267
    Aug 259
    Sept 259
    Oct 501 259 16 8
    Nov 305 370 10 12
    Dec 113 370 4 12
    Jan 205 370 7 12
    Feb 235 need bill 8
    Mar 574 need bill 19
    Apr 809 need bill 26

    PVGIS
    Fixed system: inclination=35°, orientation=0°
    Month Ed Em
    Jan 6 185
    Feb 11 298
    Mar 19 582
    Apr 24 716
    May 26 820
    Jun 26 784
    Jul 25 768
    Aug 22 682
    Sep 18 533
    Oct 12 374
    fit rate 4.36
    house load when nothing on 0.8kw
    6.72kw Pv Ja Solar 280w * 24 panels, Solar Edge inverter, South facing no shading.
    South Lake District, delightful view of Morecambe Bay. Saving up for a battery

    May Solar target 820kw
    • Exiled Tyke
    • By Exiled Tyke 17th May 17, 10:58 PM
    • 207 Posts
    • 764 Thanks
    Exiled Tyke
    A couple of thoughts.

    1. I respect Mart's calculations. I've never known him to get it wrong. So don't believe him when he says they are only his opinion. He's good

    2. Standing charges are not relevant to these calculations. They will be paid regardless of any other decision made. So ignore them for your calculations.
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    • rugbyleaguesmate
    • By rugbyleaguesmate 18th May 17, 7:02 AM
    • 227 Posts
    • 1,266 Thanks
    rugbyleaguesmate
    Thank you, yes Marts opinion was one that helped me get Pv in the 1st place!

    Mart panels installed 26th Sept so import/export starts after Sept 2016

    Have just in house one year.

    Ian
    6.72kw Pv Ja Solar 280w * 24 panels, Solar Edge inverter, South facing no shading.
    South Lake District, delightful view of Morecambe Bay. Saving up for a battery

    May Solar target 820kw
    • Martyn1981
    • By Martyn1981 18th May 17, 7:29 AM
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    • 9,306 Thanks
    Martyn1981
    Hi Mart thank you my efforts are below, struggling with format.....
    Originally posted by rugbyleaguesmate
    Hiya RLM, for a persistent waffler like me, the formatting on here is a right pain.

    If I'm reading your info right, the cross over point for export v's import seems to be around October/November with rising import v's falling export.

    I can't see export figures for the summer, but I assume they are very high, and it looks like import is a relatively consistent 9kWhs/day?

    Winter looks like a low export of 4/day in Dec but rising fast in Jan (and Nov) so perhaps better to use their low of 7/10, not the 4.

    So, my gut feeling, and ignoring all battery losses at this stage, is that on most days, on average, you have 7kWhs+ of export, and an import of 9kWhs+.

    So there's the logical smallest USEABLE battery capacity, but since you rapidly meet and exceed the 9kWh mark then the sensible useable battery size is actually 9kWh+.

    Simply for comparison, not a suggestion, the PWII has a capacity of about 15kWh, and useable of about 13.5kWh. I assume that avoiding the top and bottom of that range would reduce any loss of capacity over time, and since we are dealing with averages, not actual individual days, then a larger batt will cope with better generation days, and also provide for bad gen days, or a number of days.

    So my gut feeling is that you'd want something of that size. What do you think?


    Savings wise, and I'm going to oversimplify this, but if we say average out the Nov/Dec/Jan months to about 7kWh's, let say 6, just to be safe, and the rest of the year to 9kWh's, then you might expect (hope) to reduce import by:-
    (92 x 6kWhs) + (273 x 9kWhs) = 3,009kWhs

    3,000 x 16p = £480pa.

    But, as ET points out, is that a NSC tariff, or have you just calculated it in?

    If for example the price is say 13p + SC, then savings are £390pa.

    The UK PWII site suggests a starting price of £6,700. I assume the 'permitting costs' referred to are just a standard line as it appears in all country quotes, I don't think there are any in the UK.

    So it would take you around 14-17yrs to repay, assuming we ignore interest.

    I hope this all makes sense, but there is a lot of guesswork and assumptions thrown in, which is another good reason to carrying on waiting.

    I also think we shouldn't waste an opportunity that already exists, and this is that Germany and Australia are rolling out lots of storage systems, and I suspect wealthier mainland US households will be doing this too. So we can sit back this decade and see how the systems hold up, what their performance is, how rules change (Australia may require Li-Ion systems to be installed outside) etc etc etc.

    Any help?
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • rugbyleaguesmate
    • By rugbyleaguesmate 18th May 17, 9:00 PM
    • 227 Posts
    • 1,266 Thanks
    rugbyleaguesmate
    Lots of help Mart and a BIG thank you for taking time to look at this.

    No export figures for summer as Pv only installed in September. The 16p electric cost includes standing charge (NSC tariff). Gone through your maths lots of times and I think I agree. I think now because I don't actually spend huge amounts on electricity the opportunity to use the remaining spend has gone for now. Certainly payback of 14yrs doesn't feel palatable (will it last that long?)

    Opportunities I can see is efforts to reduce import (fancy light bulbs, remove standbye, washing when sun shines etc) or maybe ASHP to heat or air conditioning.

    Electric vehicle maybe an option also for second car.
    6.72kw Pv Ja Solar 280w * 24 panels, Solar Edge inverter, South facing no shading.
    South Lake District, delightful view of Morecambe Bay. Saving up for a battery

    May Solar target 820kw
    • ASavvyBuyer
    • By ASavvyBuyer 18th May 17, 9:25 PM
    • 361 Posts
    • 853 Thanks
    ASavvyBuyer
    ... The 16p electric cost includes standing charge (NSC tariff). Gone through your maths lots of times and I think I agree. I think now because I don't actually spend huge amounts on electricity the opportunity to use the remaining spend has gone for now.

    Opportunities I can see is efforts to reduce import (fancy light bulbs, remove standbye, washing when sun shines etc) or maybe ASHP to heat or air conditioning.

    Electric vehicle maybe an option also for second car.
    Originally posted by rugbyleaguesmate
    With the amount of electricity it appears that you are still importing, would have thought you would have been better off on a tariff with a standing charge. 16p a kWh is very high for your level of consumption.

    Certainly would advise looking at getting an ASHP like Z, Mart & we have.
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers & REUK Diverter
    + Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump
    • Martyn1981
    • By Martyn1981 19th May 17, 8:02 AM
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    • 9,306 Thanks
    Martyn1981
    Lots of help Mart and a BIG thank you for taking time to look at this.

    No export figures for summer as Pv only installed in September. The 16p electric cost includes standing charge (NSC tariff). Gone through your maths lots of times and I think I agree. I think now because I don't actually spend huge amounts on electricity the opportunity to use the remaining spend has gone for now. Certainly payback of 14yrs doesn't feel palatable (will it last that long?)
    Originally posted by rugbyleaguesmate
    My pleasure. The other method for assessing viability is to work out the unit cost of storage, and compare that to your import price, so ...

    PWII at around £6.7k divided by 5,000 cycles at 13.5kWh = 10p/kWh. So that looks good against your import rate (assuming no loss of export rate).

    But, as you don't look like you can use it to the max each year (approx 5,000kWhs, v's your displaced 3,000kWh's) then it will take you longer to get your money back, and we have to consider the life expectancy of the battery, outside of warranty, which may be absolutely fine, but personally I'd like more years and data, and to be blunt, a longer warranty.

    Sorry about the summer months, of course you don't have the figures, doh! But this could be a problem. I suspect your large system will smash the import. Great news for your bill, but less summer import, means less leccy bill that the battery can displace, so less value for money from the batt.


    It looks to me like you are in a far better position than most to make use of a big batt, and big batts are better value for money at the moment, but the numbers are still nowhere near stacking up yet.

    I think it all looks good for the future, but sadly we'll have to be a bit more patient. Perhaps an EV will boost the economics of batteries, but again we need to be careful if the batt is discharging at night when the house has an E7 tariff.

    This is why I'm a little concerned about the calculations, I can do the A + B = C stuff, I just don't know what the right calculation is yet, there seem to be multiple factors and issues coming from all directions, and varying by PV set up and household demand use too. Paracetamol anyone?


    Lastly, and very important, I don't see any reason why the UK couldn't set up a company like the Australian one, that links domestic batt owners and negotiates the sale of leccy during peak times, at peak prices. So for instance, if you are using 1kW and the batt is discharging 1kW, it may be asked to discharge 2kW, and supply grid support of 1kW. If spot prices are into the £'00's per MWh, then the households might get 10p, 20p, 30p/kWh for their leccy. This could alter the economics massively. Early days, but lots of promise.
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 19th May 17, 5:08 PM
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    • 9,306 Thanks
    Martyn1981
    This article on storage in the Western Power and Distribution (DNO) region, might be better placed on the green energy news thread, but I think it's ok here due to this bit on domestic storage:-

    Wave 1 (up to 2020) - Led by response services
    Domestic and community scale early adopters.

    Wave 2 (early 2020’s) - Co-location business models become viable
    The domestic and community storage market expands.

    Wave 3 (mid/late 2020’s) – Market expansion and new business models
    Domestic electricity storage becomes common


    WPD investigates the future of storage following ‘unprecedented’ applications

    Western Power Distribution (WPD) has launched a consultation seeking views on the potential growth of energy storage on its distribution network after receiving an ‘unprecedented’ 8GW of applications in the last 18 months.
    According to the consultation, WPD has already accepted 1.13GW of battery storage capacity as of 3 May 2017, with a further 1.1GW offered to existing applications. These projects mark a significant increase on the 2.85MW from an existing project and one that WPD is now preparing to accommodate.
    Significant increase ....... it's 1,000 times more!
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Martyn1981
    • By Martyn1981 23rd May 17, 12:45 PM
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    • 9,306 Thanks
    Martyn1981
    Just some info on battery factory build outs. Loads happening, and no Tesla is not top of the list for 2020 (predictions). So we should see a lot happening to prices, availability, choice etc etc.

    So everyone just has to be patient, like me ....... ;-)

    Germany to host two more battery factories

    Renewable Energy Is Unstoppable, Declares Financial Times
    Just 'call me Mart'. Cardiff. 5.58 kWp PV systems (2.4 ESE & 1.18 ESE & 2.0 WNW)

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