On-grid domestic battery storage

orrery

1961Nick wrote: »

I think there's a strong argument that it's now possible to get back your investment in batteries & eventually make a profit. The only real question is how long that takes
...
I Agree that if this was purely a "money saving" forum then advocating batteries would be inappropriate. However, when you add "green & ethical" to that it's probably not. More so when you consider that batteries remove the "use it or lose" mindset that surplus pv generation encourages.

I agree, but on the purely financial level, the increase in battery manufacturing capacity that is being planned and built (the pipeline) is running at about 4% per month. Jumping in now could result in a payback term that is longer, and profits lower, than someone who waits for a few years for prices to fall.

JKenH

Like Mart, above, I am really enjoying this thread. Since we got our solar panels last year I am constantly monitoring output and trying to match usage to that. I don't know at the moment whether it is love or obsession but either way solar has introduced new highs and lows into my, some would say, sad life.

While I love to wake up in the morning and see the sun shining the euphoria can soon turn to despair. I have boiled all the kettles and stored all the hot water I need for tea, coffee and cooking, the IBoost is saying water tank hot and the ASHP has been maxed out so long that the living room is too hot to sit in, the washing is done and the sun is still shining. I really hate sending power back to the grid when I know I am going to need it to power us through the evening and night.

I really want a battery again. Joefizz is right, it is more than just being about economics. It would make me happier knowing I wasn’t wasting all that solar I had spent so much money trying to produce.

But when I had the battery all I could think about was that it wasn’t doing what it said on the tin and it wasn’t a very good investment and I could put my £3000 to better use. I was very fortunate that the suppliers took my dissatisfaction with the battery on board and removed it and gave me a refund.

I suspect the vast majority of people who install solar just collect the FiT payments and are happy that their electric bills are reduced but there are a few of us as witnessed by this board for whom solar has led to a different way of living and become a hobby. Like Mart says there is nothing wrong with that and a battery is a toy that I shouldn’t need to justify any more than the £3k plus I have spent this winter upgrading my home cinema. I don’t expect a financial return from my home cinema, let alone expect it to give me payback in a few years (I will have upgraded again by then) so should I from a battery? I spend more time looking at my solar then I do watching movies!

So what is stopping me jumping back in? Well first of all, I am a member of this money saving community so whenever I come on here I will be reminded that I have made a poor investment and that will gnaw away at me. Secondly I am hoping that battery costs will fall substantially so it will at some point in the future make financial sense. Thirdly and most importantly my battery experience was poor in terms of charge and dischage rates and flexibility/responsiveness.

On that latter point, reading the positive experience of early adopters like Nick and Joefizz, I would like to think some progress has been made and there might be a product out there which will meet my goal of using as much of my own solar as I can. I hope it won’t be too long before I get back in the game.

At the moment though having been bitten once my head is ruling my heart. The persuasive cost arguments of Zeup and Mart are winning the day. I need a few more early adopters to post on here with their positive experiences to sway me the other way.

As something of a postscript, I always thought that I could make my own mind up on stuff but social media not only provides us with the information we need to make decisions but sways us towards conforming, to going with the consensus. Life always has been like that but nowadays our decisions are much more open to scrutiny and criticism in a way that wouldn’t necessarily happen face to face.
Fortunately this thread has remained very balanced and respectful and I hope it will enable others to reach a decision that works for them even if it isn’t the “correct” one.

JKenH

1961Nick wrote: »

I Agree that if this was purely a "money saving" forum then advocating batteries would be inappropriate. However, when you add "green & ethical" to that it's probably not. More so when you consider that batteries remove the "use it or lose" mindset that surplus pv generation encourages.

MSE Forums discuss all manner of money saving ideas. For instance there is one on holidays, days out and entertainment. If you are genuinely money saving then don’t buy holidays or have days out - they just don’t stand up to scrutiny on the basis of return on investment.

Some people want a battery just like others want a holiday, so maybe we need to focus more on what is the best value battery out there for those like me who want one rather than saying don’t buy one - you won’t get your money back. (One could easily make that argument for holidays but how many of us who post on this forum about batteries not being economic then go off and spend our money on a holiday?)

The battery system you have is one of the first ones to get me thinking I should get one again. I think it is great that Zeup should subject it to his rigorous analysis so we get the other point of view and then we can decide better whether we want to spend our money on one like yours, one of the alternatives discussed on here, wait a couple of years or blow it on a holiday.

1961Nick

JKenH wrote: »

MSE Forums discuss all manner of money saving ideas. For instance there is one on holidays, days out and entertainment. If you are genuinely money saving then don’t buy holidays or have days out - they just don’t stand up to scrutiny on the basis of return on investment.

Some people want a battery just like others want a holiday, so maybe we need to focus more on what is the best value battery out there for those like me who want one rather than saying don’t buy one - you won’t get your money back. (One could easily make that argument for holidays but how many of us who post on this forum about batteries not being economic then go off and spend our money on a holiday?)

The battery system you have is one of the first ones to get me thinking I should get one again. I think it is great that Zeup should subject it to his rigorous analysis so we get the other point of view and then we can decide better whether we want to spend our money on one like yours, one of the alternatives discussed on here, wait a couple of years or blow it on a holiday.

You really can't put a price on looking at the energy monitor at 23:59 and seeing just 20p - the standing charge!:laugh:

joefizz

zeupater wrote: »

Hi

No problem with anyone deciding to be an early adopter at all ... as long as passing readers are aware of realistic performance expectations it's their decision on how they justify their own purchasing decisions & what they do with their own money ...

However, there has recently been a considerable amount of information on this & other boards as well as elsewhere that tends to employ, shall we say, 'unethical' means in order to improve the economics of installing domestic battery solutions ...

Agreed. Hence my post. Its not currently about making money, however my post was aimed at the posts about losses, cash etc etc. What my post does highlight as subsequent posters point out is that if you have the money in the bank and can spend it, it will improve cashflow significantly and allow other means of moneysaving that would have been moneycosting. If I were making a similar post on another forum I wouldnt make half the statements I made above.
My point is that whilst I dont realistically expect to see a complete ROI on the battery system, it will allow me to save money elsewhere in things that dont usually get mentioned (hence the comment about going back to using my old electric lawnmower rather than the petrol one). Its not a big deal but its more about moving forward overall.
I'll reiterate, not only do I not expect the battery system to pay for itself, I expect to replace, upgrade, supplement it as time goes on.
Each year so far I have reinvested my Fit payment and some of the electricity cost savings into producing my 'system'. I then expect a possible 5 year period of stasis (unlikely in my scenario) and then perhaps the upgrade/maintenance on the system.
I bought this house (my first) 24 years ago and paid it off 5 years ago and am going nowhere ;-) So again thats a factor in my choices.
As I also mentioned I work and run my business from home, Ive had one power out for 12 hours in the last year and the battery system enabled me to continue to work, thats not really a cost you can realise in spreadsheets but even the peace of mind of that is worth the cost of the battery install (Ive spent smaller figures in the past on UPS equipment with 30 mins time).

zeupater wrote: »

Regarding automated diversion to DHW ... I take it that you are aware that the difference between your manual switching & such a solution could be multiple kW of power load above that of an automated proportional diversion system? ... before batteries it was probably a missed opportunity and with batteries it's not worth looking at now ... but as your justification for extending the battery capacity with additional modules was DHW for showers, you must be aware that proportional diversion would have been a less costly path! ....

Wood for the trees. Yes 200 quid is less than 2.2k but again its viewed as a system. If the DHW was my only consideration then possibly but again it wouldnt meet my requirements. I dont need hot water on all the time or indeed require it at specific times during the day night so a quick push button from a battery (whilst the battery is installed) completely meets my requirements.
Again I point out (as below) Im only giving my individual standpoint and comparing it with yours is pointless. Im giving another view.

zeupater wrote: »

On the kettle front ... I do understand what you're saying, but wouldn't the solution that a number of PV owners on this thread use be just as valid as a stop-gap (until battery system prices become more realistic) energy import saving solution when only generating 1kW .... a 1kW kettle!!

As I said above, thats not a justification point, its one of the things about owning the system once the decision is made. As I mentioned in my post the energy market here in NI is all ireland, back in July the generators, suppliers and regulators had no idea what was going to happen at 11:01pm on 29th March (yeah I know!) so it was more a business decision to protect my business. It wasnt scaremongering as all the small scale renewables here are purchased by a company in dublin and even knowing what level of vat/duty/whatever to charge was unknown so a lot of the wind turbine people were talking about just turning them off until they knew they were actually going to get paid. The electricity suppliers here are mostly owned by Irish companies... One of the main power stations here in NI was to be shut down in Sept as being uneconomically viable (as well as dirty) but has been kept going because noone knows whats going on. Add in a winter storm with snow like last year (the uk was about 2 days from running out of gas IIRC) and suddenly a couple of grand for a battery system is really really cheap.

zeupater wrote: »

On the £20 for the last quarter eletricity bill .... great you're doing very well, at something like 20p/day standing charge for 90 days, leaves around 12kWh of total usage for the whole quarter at the 16p/kWh you mentioned! ... those batteries must be quite good & the sun must have been shining much more in NI than it has been here ... both January & February were terrible months for generation ...

No standing charge. See my points above about extrapolating your circumstances onto mine. Im just giving a different viewpoint. My solar installer recommended going with economy 7 when I got the batteries so I could charge at night in winter. Well the standing charge alone would probably double my annual electricity bill without.
I redid my house a couple of years ago and uprated insulation, put in led lights throughout, energy saving kettles, all a++ rated appliances etc etc etc. My average usage per day is about 6kWh. Jan I generated a little under 80kwH, Feb around 200kWh, March was 332 kWh. Due to my work I generally get to take my holidays in Jan so was away for a week then.
Moving two of the E/W panels to orientate solely for Dec/Jan usage might just cover the difference or a large part of it.

As I said above, it suits my circumstances. This year I'll be away June/July and next year probably away all of January, so my generation in summer will be pretty much all export and in Jan there will be little or no import.

Not everyone is as flexible as I am but if you are you can now see where it meets my requirements.
If you have a family of 5 then I doubt its going to work for you...

zeupater wrote: »

Another issue could do with clarification if you would .... you went on a seminar last summer (2018) and as a result you purchased a battery system to add to a PV system you'd installed 2 years previously, so 2016, yet with your maximum 3.25kW system (4kWp?) you expect to be paid £400-£500?, so the 10 year payback on this would suggest somewhere around £4500 for the initial install, which you've since increased capacity by ~25% to 5.2kWp with 4 additional panels to feed the batteries ....

Yep just under 5k for initial install, 2.2k for pylontech 4.8kw and me3000sp, 1.2k for extra panels and gubbins and 1.6k for 2 extra pylontech batteries so pretty much the 10k I quoted at the start of my post.
NI rocs plus export is around 500-600 (again need another full year with the new panels for proper figures) and electricity saving per year is around 2-300, oil saving cost perhaps 100-150 but loss of income on the savings is about the same as that.
Essentially there is a grand a year Im not having to pay out (or more) by using this system and considering when I installed it electricity here was 13p a unit and now its 17p a unit...
I paid about 550 for the ashp and as it is still sitting in boxes in my hall I havent mentioned it because will need a full years data (dont intend to use it during winter just mid March to mid Oct say)

zeupater wrote: »

.... expanding on this, we (like many other PV owners) struggle to generate anywhere near an average of 1kWh/kWp per day in January, and this year we ourselves achieved around half of that, but what you're describing is that if your solar PV system effectively balanced your consumption (within £20-standing charge) then your usage must be that low that <1kWh/kWp covered your daytime usage & battery charging in January, therefore the extended logic would imply that you would have huge amounts of excess generation being exported in March & April .... else there's a large degree of smoke & mirror accounting being employed involving sign-up bonuses etc .... electricity bill of £150 (41p/day) for the whole of last year with some exceptionally good PV generation months, but only £20 (22p/day) in a winter quarter where January's generation was severely impacted by cloud ... unless there's an undisclosed reason such as a long period where the property was unoccupied, the figures simply don't seem to stack up to logical scrutiny ... can you help with reasoning/details behind the quandary the supplied information has created in order to clarify this for myself & other readers ??

HTH
Z

As I said above, it works for me and doesnt work for you. Im not saying my setup will work for you as clearly it wont. 1kWh per day in Jan sounds horrendous, my worst January generation was 48Kwh (Jan 2018). So yes as I quoted the figures above I should have excess generation in my system optimistically from mid Feb right through to the last week in Nov. Dec is my low month and before the new panels struggled each year with only around 30kwh generated in total. 50 this december with the new panels so a couple oriented completely for mid nov to mid jan might cover this but only makes economic sense if I use a couple of the e/w panels as I will probably top out sometime May/Jun and want to see which ones I can move with no real effect for the rest of the year (battery/export balance etc).
When I planned the south facing panels I had originally planned to make them tilt and would tilt them 3 times a year which would cover the shortfall. However climbing onto the garage roof to tilt them in Jan wouldnt have been a great idea. I did make the rails in a way that this can be done so I may motorise those at some point in the future as another garage weekend project (probably use a drill to turn a screw mechanism or something rather than a permanent motor drive fixture). Although I might just pick an optimum angle and leave it there if it works.

joefizz

Martyn1981 wrote: »

Thanks for the post, really interesting and informative.

But, just to be clear, you seem to be coming to a similar conclusion as myself regarding the payback period of a suitably sized battery, around 10-20yrs.

Personally, for education, hobby and general interest, I'm fine with that, but I'm reluctant to talk about it positively on here as it's a money saving site and those payback periods are outside of the warranty lengths.

I suspect the kit will last well beyond warranties, if (again) suitably sized and used sensibly, but I'm walking a tricky line when you take the three factors here into account - money saving, green and ethical, and fun/enjoyment.

Please don't think anyone is being negative, just boringly realistic so as not to mislead.

I think your post got the balance just right, and I'm loving all the incoming info from those doing, whilst I'm just talking. :T

I didnt really consider the battery payback period at all. Well I did but it wasnt a big factor, the UPS and ability to run my business was the biggest factor (well I have a 1.2kw petrol generator already for that just in case).

If there were to be payback for just that part of the system I originally put it at 12 years, now with the additional capacity and paying full vat on it (instead of reduced at install) its probably 20 years so effectively never.
As I mentioned earlier I have a couple of degrees in electronic engineering so whilst I do suspect the kit will last longer than warranty I have the capability to fix the kit beyond warranty for cost so I had also expected to replace parts as time went on.

Theres always the train of thought that this kit will get cheaper but it could also get more expensive (increased tariffs, currency fluctuations etc etc) or be rendered obsolete or indeed in 5 years time get a government who subsidises entire systems for most households rather than spending loads on new nuclear power stations.
All of that is out of my control however, but now, apart from a couple of winter months (could run the petrol generator if required - not eco and not cheap) Im pretty much energy/fossil fuel independent.
Saying that my previous electricity supplier used to be eco energy only but now they arent.


Totally agree about the not being negative comments, for the majority of people at the current price points its just not realistic from a purely economic point of view.
My view is that the money was just sitting in the bank and would have earned me about 100 quid a year as it decreased with inflation, now its earning me 1000 quid or so a year and that will increase with inflation. I'll probably not see my money back but in the meantime Im not spending out so its sort of moneysaving but you have to have that in the first place!


If only I could find a way to do to my rates bill what I have done to my energy bills... Wonder will the council take a one off payment of 10k to never send me a bill again....

zeupater

1961Nick wrote: »

I can't comment on January due to an inverter failure, but this was my best February with 117% PVGIS.

Tonight I've had a look at usage for the first 2 months of battery ownership. As I said earlier, batteries change behaviour in the same way that panels do when you first install them.

For example.....

Dishwasher - Eco instead of 65C
ASHP - Eco for maximum COP
Computers - put to sleep when I leave my desk
Tumble drier - replaced with a heat pump model rather than repair
Lights - not left on unnecessarily during the day
Washing machine - Eco program when possible

None of the above affect lifestyle one iota & previously would have used energy that would otherwise have gone to the grid.

These are the figures for import + solar usage for this Feb & March compared to last year.....

Feb -5.9%
March -9.8%

The usage figure includes round trip/standby losses so the actual domestic consumption will have dropped by slightly more. The figures are also skewed negatively by the fact that we had a gas hob last year & an induction one this year.

It's still early days, but if the next couple of months show a similar pattern then this phenomenon is worth consideration when assessing the viability of batteries.

Hi

We started improving our energy efficiencies a long time before having solar PV, and even though we were an early adopter when the FiT scheme was introduced we've continually improved ever since .... as can be appreciated, that means that we went through the habitual pattern changes you're describing years ago!

Regarding the 5.9% & 9.4% reduction in electricity imports for February & March over the previous year ... what needs to be understood is that when PV is in place the level of import depends on generating conditions, not on an average basis, but at the exact time when there's load to satisfy ... our own year-on-year reductions for the months in question were ...

Jan +4%
Feb -18%
Mar -16%

... with a quarterly total reduction of ~9% ... and we've not changed a single electrical item that could explain this difference between the two years ...

Does this mean that our non-batteries are outperforming your batteries by a factor of around two? ... no, it's simply weather related differences between two sites over two consecutive years!

Now to the really confusing quandary in the narrative you're making ... I'm having considerable issues in reconciling ... 'I can't comment on January due to an inverter failure, but this was my best February with 117% PVGIS.' ... with the following post from 31/01/2016 when you exactly matched legoman62's PVGIS analysis ...

1961Nick wrote: »

Almost identical figures - 66.7 kWh - 62% of PVGIS

... surely the two are irreconcilable, but even if they weren't because the failure was simply related to retrieval of the inverter's detailed data file, surely the 'data logger connected to the ME3000SP' would act as a second data source be able to confirm what proportion of the 66.7kWh PV generation would have been diverted to, and delivered from, the battery system ... this is really interesting considering that it's 2.2kWh/day of PV average generation, which (from previously stated generation & export figures) compares poorly in a household that directly consumed an average ~2.5kWh of PV before batteries (approx 1000kWh/year difference between generation & export) ...

At this moment I'm in two minds as to whether I've read the data wrong, am having a bad day on logical analytics, or ....



HTH
Z

1961Nick

zeupater wrote: »

...

Does this mean that our non-batteries are outperforming your batteries by a factor of around two? ... no, it's simply weather related differences between two sites over two consecutive years!

Now to the really confusing quandary in the narrative you're making ... I'm having considerable issues in reconciling ... 'I can't comment on January due to an inverter failure, but this was my best February with 117% PVGIS.' ... with the following post from 31/01/2016 when you exactly matched legoman62's PVGIS analysis ...


... surely the two are irreconcilable, but even if they weren't because the failure was simply related to retrieval of the inverter's detailed data file, surely the 'data logger connected to the ME3000SP' would act as a second data source be able to confirm what proportion of the 66.7kWh PV generation would have been diverted to, and delivered from, the battery system ... this is really interesting considering that it's 2.2kWh/day of PV average generation, which (from previously stated generation & export figures) compares poorly in a household that directly consumed an average ~2.5kWh of PV before batteries (approx 1000kWh/year difference between generation & export) ...

At this moment I'm in two minds as to whether I've read the data wrong, am having a bad day on logical analytics, or ....



HTH
Z

Hi Z

If you have another read of my post you'll see that the 5.9% & 9.8% are reductions in consumption ~ I think "import + solar usage" is clearly stated? This being the case, the level of solar production is largely irrelevant.....I say "largely" because round trip losses are recorded as 'usage' by the energy monitor. I'm sure you can see the implications of that on the data.

I really am at a loss as to why you're trying to reconcile my 117% of PVGIS in Feb 2018 with Legoman62's Jan 2016 PVGIS? If you continue to have "considerable issues" I may be able to cast some light (pun intended) on your dilemma.:)

For the record, my batteries were commissioned on 29/01/2019. The solar inverter, which failed on 30/12/18, was also replaced on this date - hence the lack of generation in January 2019.:(

Martyn1981

orrery wrote: »

I agree, but on the purely financial level, the increase in battery manufacturing capacity that is being planned and built (the pipeline) is running at about 4% per month. Jumping in now could result in a payback term that is longer, and profits lower, than someone who waits for a few years for prices to fall.

That's an argument I share, or did, or still do ...... no idea anymore!!!!!!!!

I think prices should fall by more each year than current savings, but the automotive world seems to be sucking up batts faster than supply can grow.

If I now seem confused that's because I'm now pretty damned confused.

I'm sure it'll all become clear in 5yrs, but I just don't want to wait 5 more years.

Martyn1981

1961Nick wrote: »

You really can't put a price on looking at the energy monitor at 23:59 and seeing just 20p - the standing charge!:laugh:

Am I the only one that thought, yes you can ..... 20p? :dance: