On-grid domestic battery storage

mmmmikey

Martyn1981 wrote: »

As this thread is showing, there's an awful lot to think about, but so long as we are rational and sensible, none of it is complicated, just a new learning curve, and a fun hobby.

Thanks Martyn - I suspect that this will get much more complicated as time of use tarriffs introduce extra variables to consider. On the upside, wearing my positive hat, any more complexity will make it even more fun and therefore even better value

zeupater

1961Nick wrote: »

As I've said before, the economic case for having batteries is marginal in my case, but it had reached the extremities of the ball park.

The figures for last year were:

Import 5768 kWh
Generation 3926 kWh
Solar use 997 kWh

So in my case there is plenty of solar generation being exported & plenty of scope for deploying it to the household via batteries instead.

The removal of the 'use it or lose it' mindset is an additional gain I hadn't anticipated. The potential size of the round trip loss is higher than I expected, but I'm still hopeful that it's lower than the 18% Z suggested. Taking these 2 things together, I'm probably all square with the original calculation - or hopefully slightly ahead.

Based on the March numbers, I should be able to discharge 2150 kWh pa which will mean break even in year 14. I've assumed RPI at 2.5% & ignored the fact that I may have to add another battery to the stack to compensate for degradation.

The batteries have been running for 66 days & have discharged 340 kWh ~ 365/66 x 340 = 1880 kWh. Based on that, 2150 kWh for the full year looks achievable with the best months to come.

Hi

I fully understand the marginality you mention ... however, the consideration is that if it was marginal at the outset with such a large annual electricity consumption, anything you do to increase energy efficiency and reduce unnecessary consumption simply impacts on the original marginality ... that's what I've effectively been attempting to convey for some time ...

Anyway, how are you getting on with identifying the source of your electricity usage ... it's remarkably higher than average, so do you have atypical devices, appliances or load requirements - or is it what you would classify as generally typical what a normal household would use? ... for example, you can obviously monitor whole house load & usage, but do you have a plug-in socket monitor to conduct an audit? ...

HTH
Z

1961Nick

zeupater wrote: »

Hi

I fully understand the marginality you mention ... however, the consideration is that if it was marginal at the outset with such a large annual electricity consumption, anything you do to increase energy efficiency and reduce unnecessary consumption simply impacts on the original marginality ... that's what I've effectively been attempting to convey for some time ...

Anyway, how are you getting on with identifying the source of your electricity usage ... it's remarkably higher than average, so do you have atypical devices, appliances or load requirements - or is it what you would classify as generally typical what a normal household would use? ... for example, you can obviously monitor whole house load & usage, but do you have a plug-in socket monitor to conduct an audit? ...

HTH
Z

Even though we only consume around 25% of the solar production (1mW), quite a bit of that is wasted & could be diverted to batteries for overnight use.

I carried out an audit with a plug in monitor some time ago & changed several household appliances as a result. One particular fridge freezer was consuming so much energy that the payback on the new one was just over a year! I'd always assumed that the TD was the main culprit but it actually came second to that fridge.

The problem I find with energy efficiency is that all occupants of the property need to sign up to it.......and on that score I meet considerable resistance. However, 5 years ago she did accept that we couldn't carry on as we were & has been fairly compliant with any changes as long as they didn't impact on our lifestyle - there is no way she would give up the TD for a washing line!

My longer term objective was to get the energy cost to a figure I could manage in retirement rather than what we could afford now. A 75% drop in annuity rates has made what looked like a more than adequate pension pot a lot more marginal. The difference I have made so far is having the same effect as adding £135,000 into my pension fund.....and it's those sort of numbers that focus the mind.:eek:

zeupater

1961Nick wrote: »

Even though we only consume around 25% of the solar production (1mW), quite a bit of that is wasted & could be diverted to batteries for overnight use.

I carried out an audit with a plug in monitor some time ago & changed several household appliances as a result. One particular fridge freezer was consuming so much energy that the payback on the new one was just over a year! I'd always assumed that the TD was the main culprit but it actually came second to that fridge.

The problem I find with energy efficiency is that all occupants of the property need to sign up to it.......and on that score I meet considerable resistance. However, 5 years ago she did accept that we couldn't carry on as we were & has been fairly compliant with any changes as long as they didn't impact on our lifestyle - there is no way she would give up the TD for a washing line!

My longer term objective was to get the energy cost to a figure I could manage in retirement rather than what we could afford now. A 75% drop in annuity rates has made what looked like a more than adequate pension pot a lot more marginal. The difference I have made so far is having the same effect as adding £135,000 into my pension fund.....and it's those sort of numbers that focus the mind.:eek:

Hi

So effectively the home is unoccupied during the day (well most days!) & you're a standard household (ie no business activities) that used to use around 20MWh of electricity per year on inefficient appliances etc, but, on last year's data, have now reduced that to around 6.8MWh (5768+997) ?

Not bad - for a start ... ... but are you looking to re-audit?
Z

joefizz

zeupater wrote: »

Hi

DHW & Oil fired heating relative to ambient temperatures .... I've no idea why you're protesting so much about this, but please do consider the issue you're missing ... in the winter it's cold & in the summer it's warmer, so heating is required by most people during colder months ... you use oil fired space & DHW heating more in the winter than in summer ... oil & gas fired heating systems are normally pumped systems ... pumps use electricity (100W)


.... the more hours the pump runs, the more electricity you use ... ergo, DHW & space heating during the winter generally consumes more electricity than in summer ... just 5 hours of pumping per day in January would equate to 500Wh, which alone represents a considerable proportion of average daily PV generation in January & often all of a day's production ...

.... add to this the effect of mains water supply temperature seasonality, which can vary by around (/up to) 15C ... in winter the duty on whatever heat source is used to raise DHW temperatures to 60C may therefore be 38%(55/40) higher, plus the potential for higher cylinder standing heat loss to the house itself.

Both of these are valid points which lead to generally higher winter energy consumption that the majority of people would experience, including those who would knock-back the heating system to a frost-stat setting to protect the property whilst on a winter break (as indicated but missed relevance ... 'frost-stat'!)

Sigh. Right. I'll explain this again, the DHW system was unused for 20 years since I moved from coal fired central heating to ofch, the solar panels and battery system suddenly brought that back into play again. I dont have storage space heaters but OFCH and thats not likely to change for the winter months.

Yes the pump contributes to the electricity bill but having a well insulated house and having reduced my oil consumption by half in recent years its really not that big of a factor compared to the price of oil.
I made my oil reductions when oil was previously at the price it was now, it then dropped and went back up again so on the costs to make those reductions I still havent had payback.... although if the price hadve stayed constant or increased I would have or if we'd had a series of bad winters (this one was mild where I live) then I would have needed to run the heating more often etc etc.
Which is my point you are making arguments based on your low usage and assuming for the lifetime of any system that both the price remains constant and that your usage remains constant.
My point is that 3 years ago I was at the point where you are now although my usage profile was different (again something you dont seem to understand) in that my electricity usage was generally higher in summer than winter so made it ideal for solar panels.
The oil usage has little to do with it except that the extension of the solar panels and introduction of the battery system now allow me to consider alternatives to this. Again this is the major point you are missing about my posts. Yes for _your_ setup and your assumptions it wont work for you but as Ive said initially I thought it was never going to payback for me but what it has allowed me to do is think differently (increase my electricity usage after years and years of trying to decrease it) which allows savings elsewhere. Savings using things I wouldnt have considered if Id had to pay for the electricity over the life of the product but now with effectively free running costs (apart from Dec/Jan - when most of the items wouldnt be used anyway - example later) they suddenly come into play and in fact are more moneysaving than either my current usage or allow me to do things to enhance my life that I wouldnt have normally considered (again moneysaving in mind, or at least not moneycosting).

zeupater wrote: »

Regarding January holidays, I believe that the first time you mentioned this was after the initial query on PV/battery performance relative to billed demand .... after further query on the figures previous holidays encompassing the whole of January & plans for next year were raised, but they make no difference as we're considering one thing ... this year!

Believe me, I understand what you're saying, but in effect anyone could claim being energy efficient during any month by simply turning everything off at the mains switch and going on holiday ... this being the case both with & without battery or PV systems!

Sigh again you miss the point (and I quoted the quarter, not just january) because this quarter and last years quarter are the first 1st quarters in years that have been reasonably identical in terms of my usage and patterns of usage. So its a good compare and contrast between almost identical usages with and without the battery system, hence making the decision then to expand the battery system.
Its not rocket science (although technically my masters thesis was in a rocket science related area), Im actually comparing base load with base loads in relatively similar scenarios and situations. oil has got nothing to do with it. Ive probably used more energy reading my emails today and replying here (given my computer system) than running an OFCH pump for a couple of hours, but thats completely immaterial because Im not comparing 1/2 hour running 3 32 inch monitors with heating my house on an average winter day...

zeupater wrote: »

By 'not making assumptions and using published fiddle factors', shall we all consider that your recommendation to anyone considering the cost justification of a battery system (or any other device!) should ignore the manufacturer's own specifications, industry guidelines & performance related laws of physics, then just buy on faith or sales patter ?! ...

No, and thats never been my point. What Im saying is not to solely base your decisions on manufacturers specifications (hasnt quite worked out for Volkswagen on that front) and god forbid anyone should rely on faith or sales patter (as I said my supplier recommended economy 7 because I had the battery despite the fact that the E7 standing charges would be more than I paid for electricity in total last year).

My point is not to just use figures but talk to people with real world examples.
You have mentioned your usage profile is opposite to mine (very little in summer, lots in winter). So solar doesnt make much sense to you economically. My work and usage peaks in June (dead in July but thats an NI story) and then tailors off towards the end of year but with 2 summer like weeks in December. So apart from December solar is absolutely ideal for me and a basic 4kW system would have cost less than 4k (minus solaredge) and been a done deal. Paying for the solaredge might have been seen as not economically viable but it did give me pattern data for generation (not real of course although with the ROCs meter and the input/output meter that can be more accurately ascertained). That pattern data allowed me to consider ways of actually increasing my usage after years and years of decreasing usage to maximise value to me in monetary and personal terms. So again I could see that for about 4 months of the year I could stop firing up the OFCH boiler just to heat water for a shower and occasionally the dishes. For one I used the immersion which as I said had laid dormant for 20 years and I bought a dishwasher. I didnt have to buy an all signing all dancing dishwasher and didnt need to pay any attention to energy ratings or cost of running, just initial price. Again if I set it on timer to run at midday it would only cost me to run in Dec/Jan (and some sunny days not even then).
So rather than working out initial costs + lifetime running costs I just got the cheapest one with a delayed timer and eco mode.

With the battery now I dont have to worry about midday or even running the dishwasher on sunny days. Sad to say its easy to modify behaviour to do dishes when you can fill a dishwasher rather than a sink, or putting it off cos the water isnt warm etc etc etc.
Maybe nobody else on the planet has that first world problem but the ability to do that has saved me time and effort etc etc (heard the story about the two old irish batchelor brother farmers who had 2 dishwashers, one to lift clean dishes out of,the other to put dirty dishes in - didnt need cupboards).

zeupater wrote: »

As previously mentioned, I've no problem with you or anyone else looking to purchase & install a battery solution doing so on business, ethical or interest grounds without cost justification ... what raises my eyebrows is that having stated that this was basically your approach you've expended so much effort in attempting to justify on a usage & cost basis ...

No, again you completely miss the point. I said straight off with my usage and price points for electricity at the time there was probably no real prospect of justifying it on purely cost terms in its lifetime. You make the assumption that both usage and price points were constant over that term.
Nobody can ignore the horrendous price rises in energy in the last couple of years, and that has brought the tipping point closer. As I mentioned buying the battery allows the use of DHW and upgrading the battery has allowed the use of a ASHP/Air con unit. So again whilst if you take each of those in isolation (the ashp payback should be 1-2 years with oil at current prices so that will fluctuate with oil price but certainly within the 5 year warranty) but without the battery system these wouldnt have been feasible at all.
Thats my point, rather than treating a battery system as a price point, the cost value of it being an enabler could be considered and is a huge advantage as an end user like me.
Again, I'll repeat, if you are a low user like yourself, prices go up in line with savings rates and you never expect your usage to rise then it will never make sense.
However as Ive mentioned before I see it as a 'system' (former ISO 140001 auditor) so whilst individual components of the system may in isolation be never recoverable/marginal/long finger recoverable, its looking at the system which is key. Thats the bit you are missing.


Another weird example, Im big in to bbqing/summer socialising (I mentioned the hot tub thing, have an infra red sauna etc) and a couple of years ago (pre solar) a mate of mine took me to see the new range of bbqs he was selling. Now leaving taste and other factors aside I took one look and thought who the hell would want an electric bbq? I couldnt see any point in them....
..until now...
I had a long drive today and was thinking about it on the way home (sunny weather this morning) and Ive a half a bottle of gas left for my big BBQ. Now being moneysaving Im not going to go out and buy a new electric bbq but I have the tools and capabilities to retro fit some electric heating coils into my old bbq for less than the cost of a gas refill. When would I use it, well usually sunny days or nights after sunny days.

Thats why I went for the pylontech battery system, the larger lg and tesla etc made no financial sense to me but having a 4.8Kw system (my overnight max usage would be in the region of 2.5-3kWh excluding winter) allowed me to upgrade/supplement if I found I could do more stuff/change the way I do things to facilitate me as time went on. Now Ive 9.6kwh battery and if Im going to be BBqing I wont be working so that charge is probably enough for a couple of hours bbq and an hours hot tub.
Suddenly I could be looking at cost free bbqing.
Now again a bit of a flippant example and wont apply to everyone but if you BBQ 1-2 a week in summer then its not insignificant (plus not having to use the car to run for gas bottles occasionally or having to have two in case one runs out when youve 20-30 people waiting).

Of course you could just buy the electric bbq from day one and not worry about it but this is a moneysaving site...


Oh and replace electric bbq with loads of other things for example...
Always fancied a 2nd large freezer in the garage. Going eco german costs a lot but you save a lot in running costs over the warrantied lifetime....
Or with solar and battery and use it mainly in summer months as a kegerator and in the run up to Christmas to store soups, stews, casseroles, curries, you made in the slow cooker in Sept/Oct which ensures you arent eating crap in the busy time up to christmas.... ...you can just go out and buy an inefficient 7 year old german one off gumtree for 30 quid and stick a PID on it and not really worry about running costs unless you use it Dec/Jan.


Are we learning yet?

zeupater wrote: »

Again, as raised before, we have current posting members that have already/previously purchased their own battery solution on the basis of interest and personal ethics, fully accepting the poor economics. This is fine and should be applauded as we need early adopters to drive demand, but the reality for the majority is that some form of justification is needed ... it's not really the same as normal product choice - if someone wanted a new chair because it look comfortable, or a new TV because of features that's one thing, but all we're looking at is the source & path of the electrons we will be consuming and the relative cost of those electrons ... it's simply a move from service based electron supply with no capital investment to a capital intensive alternative, therefore, for most justifying, the capital should be amortised & written down in a similar way to that a business normally would do on any capital investment ... and that's where the detail (the 'minutiae of figures' you mention) is important ...
HTH
Z

Again to reiterate, with respect you are seeing it wrongly. Seeing anything in isolation without a socio economic system around it is the wrong approach.

An example. I have a car. Sitting on my driveway for 2 days this week its a complete waste of insurance, tax, maintenance, mot money etc etc etc. Last night I drove to the west coast of ireland, had dinner with friends, drove back early this morning.
Its exactly the same car but you cant compare the two, you need to have the vision to see what and how it can provide a range of factors including economic.
As I said I never expected to see my battery itself pay for itself but the system would in about 12 years or so (more or less, all else being equal). Last year we had an exceptional summer compared to the rolling atlantic cloud for the previous 4 years in summer (july not getting above 16C in some cases) and thats what I based my calculations on. If Id based my calculations on last year it would probably pay for itself in less than ten. If electricity prices rise over the next 3 years in line with what they have over the last three it might even pay for itself in 7... Those are ifs ands and buts (like manufacturers specs). I used to work in a manufacturing environment. We worked out 97% of fails were in the first 48 hours of use. Answer? every single product was run for 48 hours off the production line. It did make some sort of sense....
Most manufacturers figures arent worth the paper they are written on in the real world. Yes, in ideal conditions and under certain parameters and providing the supplier isnt telling porkies... Extrapolated and bench measured yearly decay figures are interesting but lets be honest its not until any system is installed, operating and measured over time in a variety of conditions that true costs and returns can be evaluated. You have absolutely no experience of a system in operation/usage and are working off stats so Im not surprised you are getting it wrong.

I agree about salesmen though, to be fair to mine they were straight and honest about things, they said I'd probably not benefit from solaredge and that a battery was a waste of time for me (they were resellers for tesla, eye watering costs...), however I explained I was going to use the solar edge data as a guide for my system in operation to base decisions on my system. I email them updates every so often as they are as interested in how I get on with my usage profile/location as I am.
With going to 9.6Kw Ive probably priced in all the future expansion I can and any further investment would just be wasted. It has cost me more in real terms for this approach of piecemeal addition but Ive tuned it to be perfect for me. There is absolutely nothing I can do about Dec/Jan and at present, pointless trying. I dont really have an alternative for oil.
Saying that though im in an ideal spot for a large community wind turbine to fill those months but getting planning permission (side of a mountain, full view of everywhere) would be pretty much impossible for the correct spot.



Coming from an engineering background Id never consider myself or indeed want to be an early adopter. I jumped on solar quite literally at the last moment for rocs phases here and waited until a system like the battery one I have was available. Yes purchase might be new but as Ive mentioned before Ive worked with UPSs for decades so the technology isnt new in itself, its just the form factor for the actual battery components themselves have changed significantly.


Anyway enough of all that, if anyone does have any actual genuine questions about an up and running real world system in operation, let me know. I'll have much better data when/if I ever get the ASHP up and running.

joefizz

mmmmikey wrote: »

So I just can't see this stacking up as a technology to be deployed alongside domestic solar panels for a long time, if ever, fo an awful lot of people.

Thats why until the modular battery system came along that I couldnt make the figures work.
For a static once off, install once, idea it does make little sense, particularly where the biggest influencers of output (direction, angle) in most cases are limited by your roof.
Was talking to some people yesterday in the west of ireland where figures for PV etc dont really add up in real terms (no ROCS, no payment for export etc) but they have a part of their property with clear unobstructed views where a tilting array could be built and with the equipment they have around they already have enough lead acid batteries about for a start of a good enough battery system.

The biggest factor then of course is the weather, they live in one of the wettest places in Ireland. 30 miles down the road it would be a no brainer in real terms for what they do but if they were to follow a general install it would probably never work.

mmmmikey wrote: »

.On a more positive note, if you can sell some of that under-utilised capacity via a grid-services contract, or if you take solar panels out of the equation and use the batteries to ensure you only ever buy energy at the lowest rate on a time-of-use tarriff then the economics change significantly. We're not really there yet with either of these mitigations (unless E7 works for you) but my crystal ball is telling me that these are on the near horizon.

One of the discussions I was involved with last year was utilising various systems not too dissimilar from mine near wind farm generations. In a lot of cases the wind guys are being paid to shut down whereas if there were local networks of storage facilities (batteries being one) then they could get reduced amounts to fill the storage. The storage facilities in trial are mixed technologies with some with losses of 50% but with cheap setup and almost zero running/maintenance costs.

Its about distributing storage as part of the network. I live about 40m from a substation and wouldnt be surprised to see a mini storage facility built beside it in the next 2-3 years.
Talking to the guys on the eu funded project was one of the influencers on me getting the battery system.
After that discussion I didnt think it was a coincidence that the pylontech batteries fitted into a standard 19 inch rack.

mmmmikey wrote: »

My own prediction is that batteries will never be cost-effective for Z and many other solar panel owners but the growth in battery deployment will come through some innovatively funded scheme that sees them deployed in households without solar to take advantage of off-peak rates.

Agreed as far as cost effectiveness. As above its already cost effective for utility companies to install mini systems in each distribution box so Zs daily export is stored down the street and sold back to him at night. I can see household deployment not being promoted though as energy companies will make more with the same distributed storage and smart meters will facilitate this even more.

jcontest

Martyn1981 wrote: »

But, if we (as planned) add 4 panels of steep south facing PV at the same time as a battery (60% increase in Dec generation), and get an EV (eventually) to mop up summer excess, then things improve, but a larger battery is then needed, probably 10-15kWh to allow for 5-10kWh of almost daily EV charging.


As this thread is showing, there's an awful lot to think about, but so long as we are rational and sensible, none of it is complicated, just a new learning curve, and a fun hobby.

Some of what I worry about is also what we are going to technically be allowed to do. From that I mean those that receive FIT. I see the other post from NI who seems to suggest he does a lot of DIY type alterations to his home system, but strictly speaking the FIT doesn't allow you to make those modifications (unless you have MCS Certification + Electrical Certification).


So my system currently has a single inverter, Solar->Inverter->AC(Grid) output.
That means that, even if the inverter goes, I can't add a battery system on the solar side of things (Worse charging), It means that if I add a battery system that while it could work if the grid goes down, then while it is down I wouldn't be able to charge my battery or run my house from those solar panels. I know that "Technically" it's not a huge issue, but it does add layers of design complications AND layers of cost WITH some layers of losses!.


I wanted a micro CHP system, Tried for 2-3 years to get one installed! but no one would touch a residential install. Eventually I seen a few of them roll out. I know the UK (And world) is eager to move away from NG so seeing how they want Gas Boilers to stop being installed then I can't see how gas-fed CHP systems will be allowed. Shame really as they can be super-efficient.


GSHP's seem to be no real option in my area either due to small-ish gardens. Tho from all of the documents I have a vertical bore system would fit fine. ASHP's are great, BUT I do wonder if they actually save as much as is claimed. Quick thumb maths says a COP of 400% means that it's only going to be slightly cheaper than Gas for central heating. On top of that you can still be stuck with a separate gas hot water heating system.


To me it all ties together. If I was adding a battery system I would also do it knowing that I would be adding electric heating (ASHP/GSHP). But then I get back to the complexity of equipment being installed at my home to deal with the electrical system (and FIT and RHI).

joefizz

jcontest wrote: »

Some of what I worry about is also what we are going to technically be allowed to do. From that I mean those that receive FIT. I see the other post from NI who seems to suggest he does a lot of DIY type alterations to his home system, but strictly speaking the FIT doesn't allow you to make those modifications (unless you have MCS Certification + Electrical Certification).

Over here it has to be signed off by someone who is MCS certified, so a small fee to previous contractor to examine and sign off the work (bought the extra panels, solaredge modules off them as well, just to keep it friendly/use their discounts/minimise certification fee). Provided it all fits in with the overall footprints (max output, no referral to DNO) so my work is essentially upgrading/moving panels (which were in the original plans but garage south facing roof wasnt built in time). Its the maximum output they were concerned about hence calling them and asking what was permitted that they could sign off. I cant add any more to the system as is and be covered, but I can move stuff with just basic electric sign off (hooks, lines already in place for any future changes).

Also another caveat NI ROCs are different from UK Fit so again might be worth checking with your original installer about whats allowed and the process.
NIs ROCs system has tailed off significantly with the reduction and as a result was told the number of MCS registered installers has fallen dramatically. If theres a similar drop off in England then it might be worth looking into it.



Inverter and battery is just electrical equipment installed at home post solar inverter and not part of any of the above. Technically speaking for insurance etc it needs to be installed like any electrical changes by the relevant competent person (again could do it and get an electrician to sign off for a small fee if not deemed competent yourself, or put it all together/mount and get an electrician to check/connect up).

Not sure about battery attached to inverter, might just need installer/electrician sign off etc. IIRC the solaredge inverter I have needs an extra board? Not sure but again all the mounting/donkeywork could be done and then just connect up and sign off. Dont know though you'd need to check for your particular installation.

jcontest wrote: »

I wanted a micro CHP system, Tried for 2-3 years to get one installed! but no one would touch a residential install. Eventually I seen a few of them roll out. I know the UK (And world) is eager to move away from NG so seeing how they want Gas Boilers to stop being installed then I can't see how gas-fed CHP systems will be allowed. Shame really as they can be super-efficient.

Had a tour of one good system at local college a couple of years ago and went and spoke to my neighbours about clubbing together and getting one for a few houses. Didnt get buy in in the end as not all had the upfront costs plus planning hadnt a clue where to start! Installer was willing though and said it was straightforward enough! Paperwork was going to be horrendous, setting up 3rd party company to run, insurances etc etc, effectively setting up as a mini power company... not worth the hassle.

jcontest wrote: »

GSHP's seem to be no real option in my area either due to small-ish gardens. Tho from all of the documents I have a vertical bore system would fit fine. ASHP's are great, BUT I do wonder if they actually save as much as is claimed. Quick thumb maths says a COP of 400% means that it's only going to be slightly cheaper than Gas for central heating. On top of that you can still be stuck with a separate gas hot water heating system.

Spec sheets dont seem to tell the whole story for the ASHPs, far too limiting in data/values given, probably just a try it and see approach. Certainly thats my approach but not intending it to replace central heating during winter. Main problem I have with the ASHP I have is that the ideal place to place it is forbidden under NI planning rules so I'll have to put it in a less than optimal position for the whole house just not office/bedrooms etc. Saying that the air con/dehumidifying functions are useful to me as well. Needless to say the RHI scheme over here died a very quick death so its generally self install and they arent widely used here in domestic settings due to requiring planning permission in most cases and no RHI.

jcontest wrote: »

To me it all ties together. If I was adding a battery system I would also do it knowing that I would be adding electric heating (ASHP/GSHP). But then I get back to the complexity of equipment being installed at my home to deal with the electrical system (and FIT and RHI).

Definitely worth having a word with a good installer to see what is possible for your setup, a lot may not have a clue what you are talking about but should know about the FIT status etc. Electricians should know the electrical regs but if you have an installation already you might have a lot of the stuff there, similarly the biggest issue I have with the ASHP is the vagaries of NI planning which isnt something I first considered even applying.

zeupater

joefizz wrote: »

Sigh. Right. I'll explain this again, the DHW system was unused for 20 years since I moved from coal fired central heating to ofch, the solar panels and battery system suddenly brought that back into play again. I dont have storage space heaters but OFCH and thats not likely to change for the winter months.

Yes the pump contributes to the electricity bill but having a well insulated house and having reduced my oil consumption by half in recent years its really not that big of a factor compared to the price of oil.
I made my oil reductions when oil was previously at the price it was now, it then dropped and went back up again so on the costs to make those reductions I still havent had payback.... although if the price hadve stayed constant or increased I would have or if we'd had a series of bad winters (this one was mild where I live) then I would have needed to run the heating more often etc etc.
Which is my point you are making arguments based on your low usage and assuming for the lifetime of any system that both the price remains constant and that your usage remains constant.

.... the point being that winter DHW & space heating uses a pump, probably around 100W, which is consuming a proportion of the energy that would otherwise be diverted to the battery ... fine, but why all of the obfuscation related to the heat source, coal etc as we're not discussing that at all ... just the pump

My point is that 3 years ago I was at the point where you are now although my usage profile was different (again something you dont seem to understand) in that my electricity usage was generally higher in summer than winter so made it ideal for solar panels.
The oil usage has little to do with it except that the extension of the solar panels and introduction of the battery system now allow me to consider alternatives to this. Again this is the major point you are missing about my posts. Yes for _your_ setup and your assumptions it wont work for you but as Ive said initially I thought it was never going to payback for me but what it has allowed me to do is think differently (increase my electricity usage after years and years of trying to decrease it) which allows savings elsewhere. Savings using things I wouldnt have considered if Id had to pay for the electricity over the life of the product but now with effectively free running costs (apart from Dec/Jan - when most of the items wouldnt be used anyway - example later) they suddenly come into play and in fact are more moneysaving than either my current usage or allow me to do things to enhance my life that I wouldnt have normally considered (again moneysaving in mind, or at least not moneycosting).

... so in amongst all of that obfuscation you're effectively saying that 3 years ago your house's total annual energy purchases/import from all sources (oil, coal, logs, gas, electricity or whatever!) for a whole year was ~3800kWh ?, maybe in all of the confusion you've missed your approx 100litres/month (>12000kWh) of heating oil, so ... well that's what it seems you're saying, but lets revisit that later ...

Sigh again you miss the point (and I quoted the quarter, not just january) because this quarter and last years quarter are the first 1st quarters in years that have been reasonably identical in terms of my usage and patterns of usage. So its a good compare and contrast between almost identical usages with and without the battery system, hence making the decision then to expand the battery system.
Its not rocket science (although technically my masters thesis was in a rocket science related area), Im actually comparing base load with base loads in relatively similar scenarios and situations. oil has got nothing to do with it. Ive probably used more energy reading my emails today and replying here (given my computer system) than running an OFCH pump for a couple of hours, but thats completely immaterial because Im not comparing 1/2 hour running 3 32 inch monitors with heating my house on an average winter day...

... Yes, you quoted the electricity bill for the quarter, but also supplied average daily usage over a year & generation details for January which logically didn't stack up because they alone likely explained/exceeded the quarter's consumption ... I would have thought that anyone with a masters in rocket science would appreciate the conclusion that anyone looking at the figures would logically make ...

... so, January suddenly had a week's holiday injected, later by the whole of January in some years being a holiday month, then there's the assertion that was no holiday in January this year or last to validate comparison, followed by tales of atypical consumption patterns with heavy summer weighting, apart from the planning to not be home in in June&July, which logically means no heavy weighting at all for this period, just baseload savings through the battery in the best generation months with plenty of surplus, as if this makes not a jot of difference to your projections - or does it! .. but back to this later ...

You have mentioned your usage profile is opposite to mine (very little in summer, lots in winter). So solar doesnt make much sense to you economically. My work and usage peaks in June (dead in July but thats an NI story) and then tailors off towards the end of year but with 2 summer like weeks in December. So apart from December solar is absolutely ideal for me and a basic 4kW system would have cost less than 4k (minus solaredge) and been a done deal. Paying for the solaredge might have been seen as not economically viable but it did give me pattern data for generation (not real of course although with the ROCs meter and the input/output meter that can be more accurately ascertained). That pattern data allowed me to consider ways of actually increasing my usage after years and years of decreasing usage to maximise value to me in monetary and personal terms. So again I could see that for about 4 months of the year I could stop firing up the OFCH boiler just to heat water for a shower and occasionally the dishes. For one I used the immersion which as I said had laid dormant for 20 years and I bought a dishwasher. I didnt have to buy an all signing all dancing dishwasher and didnt need to pay any attention to energy ratings or cost of running, just initial price. Again if I set it on timer to run at midday it would only cost me to run in Dec/Jan (and some sunny days not even then).
So rather than working out initial costs + lifetime running costs I just got the cheapest one with a delayed timer and eco mode.


With the battery now I dont have to worry about midday or even running the dishwasher on sunny days. Sad to say its easy to modify behaviour to do dishes when you can fill a dishwasher rather than a sink, or putting it off cos the water isnt warm etc etc etc.
Maybe nobody else on the planet has that first world problem but the ability to do that has saved me time and effort etc etc (heard the story about the two old irish batchelor brother farmers who had 2 dishwashers, one to lift clean dishes out of,the other to put dirty dishes in - didnt need cupboards).

... again, lots of waffle with little substance other than an observation on some form of inverted seasonal usage pattern, so addressing this ...

... very little electricity use in Summer & Lots in winter!? .... talk about spin! .... as you are aware from an earlier post our electricity imports over the "previous rolling 12 months being ~3kWh/day, with a range of 2.1kWh/day in Q2 to 4.5kWh/day in Q4 ... January & December both requiring just over 5kWh/day" ... did I mention that we're running a heat-pump whilst you're not!, so what would you consider the effect of your heat-pump will be on winter month imports when it eventually gets installed, even with a battery! (consider this to be the revisitation mentioned above) ....

No, again you completely miss the point. I said straight off with my usage and price points for electricity at the time there was probably no real prospect of justifying it on purely cost terms in its lifetime. You make the assumption that both usage and price points were constant over that term.
Nobody can ignore the horrendous price rises in energy in the last couple of years, and that has brought the tipping point closer. As I mentioned buying the battery allows the use of DHW and upgrading the battery has allowed the use of a ASHP/Air con unit. So again whilst if you take each of those in isolation (the ashp payback should be 1-2 years with oil at current prices so that will fluctuate with oil price but certainly within the 5 year warranty) but without the battery system these wouldnt have been feasible at all.
Thats my point, rather than treating a battery system as a price point, the cost value of it being an enabler could be considered and is a huge advantage as an end user like me.
Again, I'll repeat, if you are a low user like yourself, prices go up in line with savings rates and you never expect your usage to rise then it will never make sense.
However as Ive mentioned before I see it as a 'system' (former ISO 140001 auditor) so whilst individual components of the system may in isolation be never recoverable/marginal/long finger recoverable, its looking at the system which is key. Thats the bit you are missing.

... here all we really see is that a (cheap / low COP / DIY?) heat-pump in an unopened box is only useful when combined with a battery, even though a number of posters to this thread already have high COP units successfully in operation & contributing towards overall energy saving without batteries ... odd really, so did you not cost justify that purchase on performance specification vs cost either?

So, ISO 14001 ... great, but I can't really follow the reasoning for mentioning it within the context of this battery discussion .... if I mentioned QMS's based around ISO900x, ISO 1400x. ISO1800x .. and on & on, and then there's things odd bits like ... SO17799, ISO2700x ... and on & on ... oh did I mention TS16949 & many, many others at detail level, would it make a difference ... probably not - and isn't that the case for any form of justification? ... apart from a business attempting to improve their environmental credentials that is, in which case the cost may be a sideline issue!

Another weird example, Im big in to bbqing/summer socialising (I mentioned the hot tub thing, have an infra red sauna etc) and a couple of years ago (pre solar) a mate of mine took me to see the new range of bbqs he was selling. Now leaving taste and other factors aside I took one look and thought who the hell would want an electric bbq? I couldnt see any point in them....
..until now...
I had a long drive today and was thinking about it on the way home (sunny weather this morning) and Ive a half a bottle of gas left for my big BBQ. Now being moneysaving Im not going to go out and buy a new electric bbq but I have the tools and capabilities to retro fit some electric heating coils into my old bbq for less than the cost of a gas refill. When would I use it, well usually sunny days or nights after sunny days.

Thats why I went for the pylontech battery system, the larger lg and tesla etc made no financial sense to me but having a 4.8Kw system (my overnight max usage would be in the region of 2.5-3kWh excluding winter) allowed me to upgrade/supplement if I found I could do more stuff/change the way I do things to facilitate me as time went on. Now Ive 9.6kwh battery and if Im going to be BBqing I wont be working so that charge is probably enough for a couple of hours bbq and an hours hot tub.
Suddenly I could be looking at cost free bbqing.
Now again a bit of a flippant example and wont apply to everyone but if you BBQ 1-2 a week in summer then its not insignificant (plus not having to use the car to run for gas bottles occasionally or having to have two in case one runs out when youve 20-30 people waiting).

Of course you could just buy the electric bbq from day one and not worry about it but this is a moneysaving site...


Oh and replace electric bbq with loads of other things for example...
Always fancied a 2nd large freezer in the garage. Going eco german costs a lot but you save a lot in running costs over the warrantied lifetime....
Or with solar and battery and use it mainly in summer months as a kegerator and in the run up to Christmas to store soups, stews, casseroles, curries, you made in the slow cooker in Sept/Oct which ensures you arent eating crap in the busy time up to christmas.... ...you can just go out and buy an inefficient 7 year old german one off gumtree for 30 quid and stick a PID on it and not really worry about running costs unless you use it Dec/Jan.

... after all of that irrelevant waffle I really don't know whether to cough, yawn, cry or laugh - but to summarise ... great, you might buy an electric BBQ & another freezer to go with your energy intensive hot-tub to help justify your battery ... fine, go ahead and maximise your summer load in an attempt to convince people that the purchase of batteries can make financial sense, but then again, why would someone with a background in ISO1400x auditing ever want to 'waste' as much energy as possible in such a frivolous way, my own experience with quatity consultants & assessors is that they tend to believe in what they do!

Again to reiterate, with respect you are seeing it wrongly. Seeing anything in isolation without a socio economic system around it is the wrong approach.

An example. I have a car. Sitting on my driveway for 2 days this week its a complete waste of insurance, tax, maintenance, mot money etc etc etc. Last night I drove to the west coast of ireland, had dinner with friends, drove back early this morning.
Its exactly the same car but you cant compare the two, you need to have the vision to see what and how it can provide a range of factors including economic.
As I said I never expected to see my battery itself pay for itself but the system would in about 12 years or so (more or less, all else being equal). Last year we had an exceptional summer compared to the rolling atlantic cloud for the previous 4 years in summer (july not getting above 16C in some cases) and thats what I based my calculations on. If Id based my calculations on last year it would probably pay for itself in less than ten. If electricity prices rise over the next 3 years in line with what they have over the last three it might even pay for itself in 7... Those are ifs ands and buts (like manufacturers specs). I used to work in a manufacturing environment. We worked out 97% of fails were in the first 48 hours of use. Answer? every single product was run for 48 hours off the production line. It did make some sort of sense....
Most manufacturers figures arent worth the paper they are written on in the real world. Yes, in ideal conditions and under certain parameters and providing the supplier isnt telling porkies... Extrapolated and bench measured yearly decay figures are interesting but lets be honest its not until any system is installed, operating and measured over time in a variety of conditions that true costs and returns can be evaluated. You have absolutely no experience of a system in operation/usage and are working off stats so Im not surprised you are getting it wrong.

... great, so what you're effectively saying in all of that is that the testing regimes to ISO standards & results obtained from labs such as TUV should be ignored, because they're not 'worth the paper they are written on' ... and this is the opinion of an ISO assessor, which from the start has be querying the relevance of the 'minutiae of losses and economic return'?

I fully understand that you are looking to roll the economics of your battery system into the overall performance of a renewables+storage solution to balance out gains & losses and account for performance on a system basis ... great, but that's not the way it works if you already have a PV installation as the battery addition is an incremental change, so this should be recognised & appropriately accounted for, unless the decision comes down to personal ethics, pure interest or something like business continuity or credentials purposes, which I believe you mentioned a few volumes of unrelated waffle previously ....

I agree about salesmen though, to be fair to mine they were straight and honest about things, they said I'd probably not benefit from solaredge and that a battery was a waste of time for me (they were resellers for tesla, eye watering costs...), however I explained I was going to use the solar edge data as a guide for my system in operation to base decisions on my system. I email them updates every so often as they are as interested in how I get on with my usage profile/location as I am.
With going to 9.6Kw Ive probably priced in all the future expansion I can and any further investment would just be wasted. It has cost me more in real terms for this approach of piecemeal addition but Ive tuned it to be perfect for me. There is absolutely nothing I can do about Dec/Jan and at present, pointless trying. I dont really have an alternative for oil.
Saying that though im in an ideal spot for a large community wind turbine to fill those months but getting planning permission (side of a mountain, full view of everywhere) would be pretty much impossible for the correct spot.

Straight & honest salesmen? .. that's fine and it's good to see the advice they gave, but I doubt that you'll be able to change their minds by emailing them the quality of data & level of irrelevance you've subjected us all to recently ... have they requested a visit to see how wrong they were yet? ..... anyway, wind farm? ... there'll be plenty of that to farm by the recent ISObars then ... ... so capture away! ... sorry, it must all of the incidences of 'I'm not cost justifying, but here's my cost justification' posts that seem to have appeared recently ... my head should be spinning ... but it's not.

Coming from an engineering background Id never consider myself or indeed want to be an early adopter. I jumped on solar quite literally at the last moment for rocs phases here and waited until a system like the battery one I have was available. Yes purchase might be new but as Ive mentioned before Ive worked with UPSs for decades so the technology isnt new in itself, its just the form factor for the actual battery components themselves have changed significantly.

Anyway enough of all that, if anyone does have any actual genuine questions about an up and running real world system in operation, let me know. I'll have much better data when/if I ever get the ASHP up and running.

Phew, finally at the end, what a po-lava! .... so to conclude ...

... an engineering background & reticence to apply the approach an engineer would naturally employ, which would almost universally include consideration, the application of electrical & mechanical laws, specifications and the odd cost justification .... in my experience that would be pretty close to unique!

Did I mention that our electricity consumption already includes a small ASHP? ... of course, but I did say that it would be revisited later ... ... so there you go!

Coffee time ... :coffee:


HTH
Z

zeupater

jcontest wrote: »

... So my system currently has a single inverter, Solar->Inverter->AC(Grid) output.
That means that, even if the inverter goes, I can't add a battery system on the solar side of things (Worse charging), It means that if I add a battery system that while it could work if the grid goes down, then while it is down I wouldn't be able to charge my battery or run my house from those solar panels. I know that "Technically" it's not a huge issue, but it does add layers of design complications AND layers of cost WITH some layers of losses! ...

Hi

Have you researched the term 'islanding' .... been around for a considerable time (well, longer than we've had out system!), the only thing is how to justify the cost against occasional outages & whether there's a suitable solution for your inverter etc !

HTH
Z