Your browser isn't supported
It looks like you're using an old web browser. To get the most out of the site and to ensure guides display correctly, we suggest upgrading your browser now. Download the latest:

Welcome to the MSE Forums

We're home to a fantastic community of MoneySavers but anyone can post. Please exercise caution & report spam, illegal, offensive or libellous posts/messages: click "report" or email forumteam@.

Search
  • FIRST POST
    • Martyn1981
    • By Martyn1981 5th Dec 16, 3:57 PM
    • 6,492Posts
    • 10,645Thanks
    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.
    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.
Page 16
    • tony541
    • By tony541 13th Feb 18, 11:20 PM
    • 25 Posts
    • 11 Thanks
    tony541
    I've had a solar electric system on a house in Spain a few years back and I came to the conclusion that the cost of batteries makes these battery storage systems as not being cost effective unless subsidized. I'm not up to date with modern battery technology but I doubt that in practice they will perform as stated and are too expensive. It wouldn't be so bad if modern technology was bringing the price of batteries down but it isn't at the moment.
    Solar energy is a wonderful thing but the problem is that accountants become involved and price any motive to use them out of bounds of most sensible people.
    • Martyn1981
    • By Martyn1981 14th Feb 18, 8:12 AM
    • 6,492 Posts
    • 10,645 Thanks
    Martyn1981
    Mart, thanks for the heads up on the PETE project.
    Got in touch with them to understand the numbers..£2899 for lithium ion 4KWh (warranty 10 yrs) or £1899 (warranty 5 yrs) for lithium ion 4KWh (second life). The prices are all inclusive.
    From the forum I understand that this may suffice for powering the heartbeat of the house, during night time.
    Does this look to be good value?
    Originally posted by django01
    Hiya, I'm in two minds, or heart and head.

    Head says that's a lot, and you will probably only breakeven.

    Heart says that I want to play with a battery.

    When you say inclusive, does that mean everything, including install?

    Do some number crunching and see how much potential you have over a year for changing export into reduced import, and see how much that will save. My thought would be that the 5yr batt may be good for 10yrs ..... what do you think?

    I'm also seriously thinking of switching to Solarplicity at the moment for a no standing charge account which works out cheaper for me, with no battery plan today, so perhaps for you, it might save a bit more depending on what tariff you are on. [Note, beware the leccy cost estimate as it deducts LED savings from whatever you enter, so beef up your figure by 12%.]

    Edit - also, are you happy to just breakeven, whilst enjoying the experience, and perhaps gaining the knowledge/experience for a 'better' battery in 10yrs?
    Last edited by Martyn1981; 14-02-2018 at 8:13 AM. Reason: Added an edit
    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.
    • ASavvyBuyer
    • By ASavvyBuyer 14th Feb 18, 8:29 AM
    • 674 Posts
    • 1,687 Thanks
    ASavvyBuyer
    I'm also seriously thinking of switching to Solarplicity at the moment for a no standing charge account which works out cheaper for me, with no battery plan today, so perhaps for you, it might save a bit more depending on what tariff you are on. [Note, beware the leccy cost estimate as it deducts LED savings from whatever you enter, so beef up your figure by 12%.]
    Originally posted by Martyn1981
    Hi Mart,

    If you are thinking of switching to Solarplicity take a look at their reviews on the Energy Board.
    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 14th Feb 18, 8:33 AM
    • 6,492 Posts
    • 10,645 Thanks
    Martyn1981
    Hi Mart,

    If you are thinking of switching to Solarplicity take a look at their reviews on the Energy Board.
    Originally posted by ASavvyBuyer
    That's why I'm still 'only' thinking about it!
    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.
    • orrery
    • By orrery 14th Feb 18, 10:20 AM
    • 540 Posts
    • 452 Thanks
    orrery
    ...It wouldn't be so bad if modern technology was bringing the price of batteries down but it isn't at the moment...
    Originally posted by tony541
    It has, and fast. Batteries were on a 14% reduction per year curve when used for laptops and phones but since motor manufacturers have started to put money in it has ramped up (ramped down ?) to a 20% reduction curve. The power electronics will be on a similar curve, but the installation isn't likely to come down much.

    As we see variable time-of-day tariffs being introduced with series 2 smart meters, then the economics will become more attractive. We are also likely to see the utilities offering them cheap (or for free) if they can utilise the stored power.
    4kWp, Panels: 16 Hyundai HIS250MG, Inverter: SMA Sunny Boy 4000TL, SolarImmersion
    Location: Bedford, Roof: South East facing, 20 degree pitch
    Nissan Leaf, TADO Central Heating control
    • tony541
    • By tony541 14th Feb 18, 11:39 AM
    • 25 Posts
    • 11 Thanks
    tony541
    Martyn,

    I would do yourself a favour and give batteries a miss. It will cost you money in the long run. I'm convinced no battery is going to last 10 years unless you take only less than say 25% out of it per day. And in the uk you cant guarantee that the sun willl shine the next day to charge it up again. Unless the government give decent incentives to go solar give it a miss. Batteries are going to cost you and grid tie inverters are costly to change when they break down., I dont think most inverters are guarenteed past 5 years.
    I think if the government were serious about global warming they would give decent incentives to solar hot water systems and grid ties systems but instead they are putting in billions to the world global warming scam where the money that could be used for incentives to households in the UK will be going into the hands of big companies and squandered in directors take offs and share holder dividends.
    Last edited by tony541; 14-02-2018 at 12:12 PM.
    • Martyn1981
    • By Martyn1981 14th Feb 18, 12:18 PM
    • 6,492 Posts
    • 10,645 Thanks
    Martyn1981
    Martyn,

    I would do yourself a favour and give batteries a miss. It will cost you money in the long run. I'm convinced no battery is going to last 10 years unless you take only less than say 25% out of it per day. And in the uk you cant guarentee that the sun willl shine the next day to charge it up again. Unless the government give decent incentives to go solar give it a miss. Batteries are going to cost you and grid tie inverters are costly to change when they break down., I dont think most inverters are guarenteed past 5 years.
    I think if the government were serious about global warming they would give decent incentives to solar hot water systems and grid ties systems but instead they are putting in billions to the world global warming scam where the money that could be used for incentives to households in the UK will be going into the hands of big companies and squandered in directors take offs and share holder dividends.
    Originally posted by tony541
    Hiya, many of the Li-ion batts are now coming with 10yr warranties. An an on roof option is offering 20yrs. Also worth considering the life cycles with many now stating 6,000+ even 8,000+, and even then that's not when the batt is dead, but when it's fallen to around 70% capacity, which itself is fine if the batt is oversized on day one.

    The LA (lead acid) batts are best not discharged more than 50% or DoD (depth of discharge), and will last longer at 25% DoD, but the li-ion are rated to about 80% DoD.

    So the Tesla Powerwall II at half the price, or twice the warranted life expectancy works out at around 5p/kWh of use, which is worth it, for me, and I expect some combination of both factors in the next few years. Also deals are starting to appear where battery energy is being bought off householders at peak periods increasing the value of that stored PV gen.

    Inverter warranties of 10-12yrs can be found, and extending warranties to 20yrs is pretty cheap, I think my Solaredge HD inverter can be extended to 20yrs for about £100, or 25yrs for about £200, but the installers upped it to 20yrs for me.

    You are right that we can't guarantee the sun in the UK the next day, which is kinda where the argument for a larger batt fits in, rather than a minimal size batt, but again, need to wait for prices to fall, and they are, slowly.
    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.
    • pile-o-stone
    • By pile-o-stone 14th Feb 18, 1:49 PM
    • 37 Posts
    • 32 Thanks
    pile-o-stone
    instead they are putting in billions to the world global warming scam
    Originally posted by tony541
    Do you not believe in Human induced climate change?
    3.68kW Split E/W & 1.5kW East solar arrays.
    • tony541
    • By tony541 14th Feb 18, 3:20 PM
    • 25 Posts
    • 11 Thanks
    tony541
    Do you not believe in Human induced climate change?
    Originally posted by pile-o-stone
    No, is the answer, at least not wholly. If it were to be true then the way countries are going about reducing carbon emissions is rather more to make profits than the reduction of emissions. For example, the billions the uk has signed up to the 'global warming' scheme could pay for subsidized water heating and solar electric in most houses in the UK. If the gov. were to do this the Utilities would lose billions in profit ., it's not going to happen.
    In Spain, the Utility !!!!!s have persuaded the government to make owners of solar electric pay the gov. a charge for the priviledge, so not many householders in Spain are going this route.
    • tony541
    • By tony541 14th Feb 18, 3:46 PM
    • 25 Posts
    • 11 Thanks
    tony541
    Hi Martyn,

    Thanks for the technology update, things are certainly improving and one just has to see how many miles that electric bikes are doing now. We are getting there apart from the costs of purchasing involved.
    In the UK I would argue that until the gov, bring back realistic subsidies then solar electric systems wont be feasable until prices come down by some 50%. I think the gov/utilities dont want to lose their easy profits and so have put the brakes on everyone going solar even at the expense of the global warming, profits must come first.
    I think solar hot water is very viable for most people now but not electric.
    I understand your desire to be green as I was the same and it is a fascinating subject. But I think some governments, uk included, are having a trade-off between being green and their loss of income from having too many householders producing cheaper electricity from solar. And, of course our weather puts us at a big disadvantage too.
    If I was young enough to get the benefits from long payback times, I would consider solar hot water first, but then a combi boiler is cheap too, then a grid-tie system second. I would give battery systems a miss until/if there are real incentives to take the risk.

    If a bank of panels plus a 10kw battery system was say £10000, which is probably too cheap a price, then how many years would it take to break even?

    ps I would take the guarantee and performance figures with a pinch of salt as these will be inflated best case figures, riddled with small print clauses, and in reality it doesnt work like that. If you are flush with money or want to get into the industry then it may a reason to buy a system to see the pitfalls and benefits in action.
    Last edited by tony541; 14-02-2018 at 3:59 PM.
    • zeupater
    • By zeupater 14th Feb 18, 4:11 PM
    • 4,049 Posts
    • 5,216 Thanks
    zeupater
    ... If I was young enough to get the benefits from long payback times, I would consider solar hot water first, but then a combi boiler is cheap too, then a grid-tie system second. I would give battery systems a miss until/if there are real incentives to take the risk ...
    Originally posted by tony541
    Hi

    It's almost certainly the case that (even with the much reduced FiT rates) installing solar PV would provide the homeowner with more energy flexibility and a better ROI than solar thermal would, even if accessing the RHI scheme.

    There's a recent take on Solar PV vs Thermal on this link ... Solar PV & Thermal: One or both ? .. which seems to conclude that PV is now the better solution if space permits.

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • Martyn1981
    • By Martyn1981 14th Feb 18, 4:44 PM
    • 6,492 Posts
    • 10,645 Thanks
    Martyn1981
    If a bank of panels plus a 10kw battery system was say £10000, which is probably too cheap a price, then how many years would it take to break even.
    Originally posted by tony541
    That's probably doable today. A 4kWp system for £5k, plus £5k for a Tesla PWII (at reduced VAT rate). Assuming a decent discount from the installer for having both.

    Break even, if we ignore lost interest (naughty, but I'm tired).

    Then around £500pa from FiTs, export and leccy savings, so 20yrs.

    I appreciate that this is not great, but it's still early days for batt storage, prices will fall both from expanded production, and reduced install costs. Also the opportunity to sell stored leccy to the grid could add significantly to this as the business model grows - In Aus folks have at times, been selling at A$1/kWh (56p/kWh) when peak prices hit A$1,400/MWh.

    Regarding AGW I have no doubts. The experts are certain, and this has only grown and become more consistent over the last 50yrs. The scientific papers produced by the FF industry also confirm AGW, though these were successfully hidden for decades. As no peer reviewed scientific papers oppose AGW, nor provide an alternative to why the planet is warming when we are in a cooling period, who am I to disagree.

    From an insurance point of view, if there was a 97% chance of serious harm and financial loss, you would take action. Even if the risk was 3%, you would take action, so either way, spending money is worth it. After all:-

    What if it's a big hoax and we create a better world for nothing?
    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.
    • zeupater
    • By zeupater 14th Feb 18, 4:55 PM
    • 4,049 Posts
    • 5,216 Thanks
    zeupater
    That's probably doable today. A 4kWp system for £5k, plus £5k for a Tesla PWII (at reduced VAT rate). Assuming a decent discount from the installer for having both.

    Break even, if we ignore lost interest (naughty, but I'm tired).

    Then around £500pa from FiTs, export and leccy savings, so 20yrs.

    I appreciate that this is not great, but it's still early days for batt storage, prices will fall both from expanded production, and reduced install costs ...
    Originally posted by Martyn1981
    Hi

    Simply looking at the price differential between Tesla's standard and extended range trucks gives an idea of where the price of batteries will be going over the next few years .... I'll be watching carefully for Powerwall2 and other domestic battery system price movements, but will be staying clear until a fully installed unit is available for well under £150/kWh and probably much closer to the £100 mark ... unless there's an incentive scheme to kick-start the home energy storage market!

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • silverwhistle
    • By silverwhistle 14th Feb 18, 10:15 PM
    • 1,706 Posts
    • 2,247 Thanks
    silverwhistle
    It's almost certainly the case that (even with the much reduced FiT rates) installing solar PV would provide the homeowner with more energy flexibility and a better ROI than solar thermal would, even if accessing the RHI scheme. Z
    Originally posted by zeupater

    I haven't read your link, but I'd add that putting in cabling is a lot easier than retrofitting piping.

    I get hot water from solar (looking forward to tomorrow's forecast sun!) by the simple expedient of an electric immersion heater in an existing tank. Solar hot water would have been a real pain.
    • zeupater
    • By zeupater 14th Feb 18, 10:55 PM
    • 4,049 Posts
    • 5,216 Thanks
    zeupater
    I haven't read your link, but I'd add that putting in cabling is a lot easier than retrofitting piping.

    I get hot water from solar (looking forward to tomorrow's forecast sun!) by the simple expedient of an electric immersion heater in an existing tank. Solar hot water would have been a real pain.
    Originally posted by silverwhistle
    Hi

    The pipe runs aren't too bad if the cylinder is upstairs and there's a loft above it ... it's just a case of replacing the existing cylinder and running some semi-flexible insulated tubing up into the loft and through the roof to where the panels are ....

    The main thrust of the article seems to be that thermal has stood still and watched as PV has gobbled up their market with a more flexible form of energy ... the conclusion is interesting and pretty damning, seeming to suggest that when home battery prices fall the thermal market will seriously suffer ...

    ... Photovoltaic and proportional diversion technologies have seriously eroded the base domestic hot water provision market position and the provision of affordable and justifiable battery storage systems will accelerate this process. Apart from a few cases where maximising performance over a limited area is important, unless the installed costs of UK solar thermal are seriously reduced over the next few years, it's highly likely that the market for the product will collapse, this likely being the case in many high-latitude countries ...
    On the hot water front, we're starting to get some decent temperatures from our thermal system already, around 40C on an almost depleted cylinder earlier this week, but tonight needed a slight 'top-up' from the GCH after a couple of dull days ... if (and that's a big if!) the forecast on the BBC red button is right the next 3 days don't look too bad so we might get some really hot water and start to wind down the gas usage ....

    HTH
    Z
    Last edited by zeupater; 14-02-2018 at 11:00 PM. Reason: +e
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • pile-o-stone
    • By pile-o-stone 15th Feb 18, 8:55 AM
    • 37 Posts
    • 32 Thanks
    pile-o-stone
    Do you have a pressurised solar thermal system Z? Does the pressure ever have to be topped up and do you have to refresh the antifreeze inside the pipework? I read a report on solar vs thermal and the major point for me was the ability to use the generated energy from PV for something more than just heating water, the other points in the article were about the ability for solar thermal to 'destroy itself', where it either freezes in winter or boils in summer and that maintenance was a lot more than the 'fit and forget' of solar PV. I felt that this was probably a little overblown and would be interested to know if this is actually an issue?
    3.68kW Split E/W & 1.5kW East solar arrays.
    • zeupater
    • By zeupater 15th Feb 18, 2:26 PM
    • 4,049 Posts
    • 5,216 Thanks
    zeupater
    Do you have a pressurised solar thermal system Z? Does the pressure ever have to be topped up and do you have to refresh the antifreeze inside the pipework? I read a report on solar vs thermal and the major point for me was the ability to use the generated energy from PV for something more than just heating water, the other points in the article were about the ability for solar thermal to 'destroy itself', where it either freezes in winter or boils in summer and that maintenance was a lot more than the 'fit and forget' of solar PV. I felt that this was probably a little overblown and would be interested to know if this is actually an issue?
    Originally posted by pile-o-stone
    Hi

    The system is sealed & has a pressure expansion vessel to raise water boiling point when stagnation happens. Our system is well designed to match our hot water usage so stagnation is rare, but on the odd occasion the solar circuit fluid approaches somewhere around double the temperature of boiling water.

    We keep an eye on the condition of the 'glycol' using a small window in the system, but as it doesn't overheat too often it's not really a problem ... you could run the system without anti-freeze and use have the controller cycle the system according to sensor temperatures to prevent freezing if it's a worry.

    I agree that energy provided by PV has more uses and is therefore likely to be of more use to homeowners, been saying it for years ... it's also raised in the linked article, so it looks like I'm not the only one !.

    As for thermal's ability to 'destroy itself', that's where balancing the design comes into play ... oversize the collector area compared to hot water storage in a cylinder & you'll have hot water all year, but stagnation will occur almost every day in the summer - same for the storage:usage ratio ... the less stress there is on the system, the longer it'll likely last ...I know of a system which is still working after over 40 years after some early 'teething' problems (undersized cylinder & self-built control!), so as long as an installation is well thought though there's no reason to expect that any other reasonable system shouldn't last that long too! ... yes it does need a little more TLC than a PV system, but not as much as a PV salesman would describe!

    Over the past couple of days I've noticed that our system has a little air in it which is causing noise as it passes through the cylinder coil - it's probably the same amount as has been there for years, but it seems that all of the small bubbles have combined, so I'll either need to separate & vent this out at some time or leave it for the pump to chop into smaller ones as the temperatures & run time increase ... also, we have some discolouration of a couple of tubes, doesn't look like blown vacuum, but maybe replacement or just cleaning, maybe nothing, but that's 'maintenance', similar to panel, cable, isolator & inverter issues which need to be accepted with PV!

    I think that the relative efficiencies raised in the article are the reason why a requirement for thermal will continue and agree that the combination of thermal & PV provides a really good overall solution .... For comparison, so far today our PV has generated just under 7kWh, with the thermal collecting over 4kWp.t ... same roof, same orientation, same day just that the thermal covers 1/4 of the area of the PV ... still looking good for when battery prices fall ..

    HTH
    Z
    Last edited by zeupater; 15-02-2018 at 2:29 PM.
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • ASavvyBuyer
    • By ASavvyBuyer 22nd Feb 18, 11:22 AM
    • 674 Posts
    • 1,687 Thanks
    ASavvyBuyer
    Just noticed that Octopus Energy have launched an "Agile" tariff.

    https://octopus.energy/agile/

    Could make the economics of having a battery worthwhile if able to charge it up from solar PV during the day & import when rates are low.

    This could cancel out the need to import from 4pm-7pm when the rates are very high.
    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
    • pile-o-stone
    • By pile-o-stone 23rd Feb 18, 9:45 AM
    • 37 Posts
    • 32 Thanks
    pile-o-stone
    Thanks Z, lots of good information. Always good to hear from people who are actually using a particular technology.
    3.68kW Split E/W & 1.5kW East solar arrays.
Welcome to our new Forum!

Our aim is to save you money quickly and easily. We hope you like it!

Forum Team Contact us

Live Stats

724Posts Today

6,998Users online

Martin's Twitter