On-grid domestic battery storage

joefizz

zeupater wrote: »

.... 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 hear source, coal etc as we're not discussing that at all ... just the pump

Youve completely lost me.

Let me explain. Again.

I dont have either in winter so no pump. This DHW you speak off is an immersion heater used in summer. You know, electrical coil immersed in hot water tank. That thing.
I dont have space heaters so really dont understand why you keep bringing that up.

The only pump I have is when I turn the CH on to circulate the hot water from the boiler to the radiators. Its only on for at max a couple of hours per day in the coldest weather and yes its about 100W. I think this winter in any 24 period the longest it was on for 4 hours. (mild winter as mentioned).

So this first quarter maximum pump usage for heating the house was 400wh one day, most days 2-2.5hr was enough.
Understand now?
Add in one touch kettle, pre frozen meals (courtesy 2nd freezer etc all detailed) led lighting, little work on in Jan requiring heavy kit so mostly laptop work, induction hob, expensive low energy tv etc etc and its no surprise I use way less electricity than you in Jan with your ASHP etc.

zeupater wrote: »

... 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 ...

No, never stated that anywhere, have always divorced oil from electricity and have given the figures for oil. Reduction over the years from two 1000L fills per year to roughly one 1100 to now lower than that and possibly half that eventually. Ive pretty much brought the oil down as far as I can get it as far as that side of the infrastructure goes (glazing, insulation, ventilation, rads, thermostatics etc etc)
ASHP and using immersion heater in summer facilitated by solar and battery system may lower the oil usage more but again dont have any data for that yet.

As for electricity I have detailed usage data going back to when I bought this house 25 years ago... as I said I have a couple of degrees in it so naturally....

zeupater wrote: »

... 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

No, they just didnt stack up for you, despite repeated explanation and going on your repeated misunderstandings and incorrect assumptions (see pump explanation above) its not logic.

zeupater wrote: »

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 ...

Atypical for you perhaps, but not for me. Again I really dont get if you are just being obtuse or really really thick.

Yes last year I worked every day June and July, this year I am working every day June and July only in the USA. Whats so difficult to understand about that? That might be atypical for you but its about 6 years since I worked away during the summer but that used to be a regular occurence (hence why never considering PV as I was away when it would be most effective).
As I keep pointing out all of this works for my usage, not your assumptions and misunderstandings about my usage.
Again let me explain in more simple details even an 8 year old can understand. I work from home. Every job I do has pretty much the same power consumption. In January theres no work around so I do 2-3 jobs in January. In May/June /July I do at least 10 times that each month. Is that really so difficult to understand, that for somewhere who works to daylight schedules does more work when theres more daylight? As I mentioned before July can be quite quiet because its the two week business holidays over here.

zeupater wrote: »

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

I do think you are just being thick now, you are the one with the inverted seasonal usage pattern ;-) Well compared to me you are.

zeupater wrote: »

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) ....

Ummm, err, again you are really being thick with this. Ive pretty much said in every post the heat pump is only to be used shoulder to shoulder through the summer to use the excess pv/battery and stop me using oil in the summer.
Ive repeatedly said it wouldnt be used in winter and as yet Ive found no replacement for oil in Dec/Jan.

zeupater wrote: »

... 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,

See post above, dont care about cop, its about using excess PV/battery during shoulder/summer months for heat/air con. COP is immaterial if it takes the load off the oil, which is the expensive bit.
As I mentioned the cheap low COP DIY ashp is to lower oil usage only. If tech spec is to be believed it will pay for itself in less than 2 years, if not 3-4. In fact its a more complicated equation than just COP and heat output, if it manages to move my oil purchase window by just 1.5-2 months it could move my annual buying pattern into cheaper summer months.....

zeupater wrote: »

So, ISO 14001 ... great, but I can't really follow the reasoning for mentioning it within the context of this battery discussion

You do seem to have a lot of difficulty following most contexts. Its in reference to discussions about systems as a whole, from conception through to disposal. Environmental systems consider the whole system and its whole lifecycle, not individual components of it. The clue is in the name Environmental Management System.

zeupater wrote: »

. 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!

You dont know much about auditing then do you? Its not about wasting energy, its about using the available energy in different ways.

Wasting money is watching all that excess going out to the grid and getting paid a pittance for it only to have to rebuy it back later that day, the next cloudy day or the next minute by running a higher than output appliance.
A successful audit would say, why are you doing this and what can you do to rectify it? Thats of course if you recognise it at all.

zeupater wrote: »

.
... 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'?

Nope. With regards to manufacturers spec sheets there are two types of people. Those who read the spec sheets and those who write them. I was one of the ones who write them.
According to Boeing and the FAA planes shouldnt have nose dived into the ground, the specs said so. Real world experience says different in some cases.
Im one of the guys who takes the specs sheets, implements them and then measures the results and compares _for me_. Others just read off spec sheets and make assumptions. We all know the definition of 'assume'.

zeupater wrote: »

.
I fully understand that you are looking to roll the economimics 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 ...

FINALLY!!! ;-)

zeupater wrote: »

.
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,

Says you. Again thats your opinion. You could argue that you should separately account for putting a new kitchen into a house and that it has no bearing on the overall marketability of the house, just the kitchen. There is an argument for that, granted.
You are choosing to audit one component of a system, Im auditing the system as its the system Im paying for and Im getting it all to work together. At the end of the day its all money into and out of my account which is the aim and overall important thing. The doing as much as I can to divorce myself from fossil fuels is also the aim. Some parts of the system to accomplish this will inevitably cost more and not pay for themselves but carry the aim of the system and without it the goals and aims dont move forward.
I cant achieve most of my goals with PV alone, having a battery alone would be stupid (well I have had it in the past as pure UPS, so maybe not stupid in context), having ASHP alone may be right in certain conditions, but probably not if including cost if gas/oil are available. Its all about the system and how components work together.
Its not about post justifying anything, its about planning out a system, implementing, measuring results, tweaking and then going through iterative cycles. If Id just looked at battery spec sheets vs price then as Ive mentioned before it would have been thrown out (as I did when only tesla/lg were available to me) but another system became available which would allow my overall system to move forward and achieve my goals. The bolts and frames on the roof dont add to my system either but they stop the panels falling into my garden.... all part of the system.

zeupater wrote: »

.
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 & irrelevance you've subjected us all to recently

I take it you arent in business either? Any decent businessman will be looking for all ways to maximise income for minimum outlay. If they can see how they can make money from similar setups, they will. Its that simple, particularly if someone else is stumping up the cost and willing to share their data with you.

Its not about being right or wrong but ability to offer more than one solution at a range of price points. Some people will pay for a nice shiny tesla box on their wall if for nothing other than a talking point, others may be looking system solutions, so better to offer other options.

zeupater wrote: »

... 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!

Its quite clear your experience of all of the above is very limited. In every single post starting with including standing charges, 100w pumps on all the time, etc etc you have made multiple assumptions and misconceptions. Even in this post you keep talking about inverse usage patterns despite not even considering that you are the one with an inverse pattern to me (which you do have). That shows you have no engineering experience because everything in your posts are based on your own assumptions and misinterpretations whereas engineering is based on specs, implementation, measurements, results, repeat.

zeupater wrote: »

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!

Maybe that explains why your winter use is the inverse of mine? I dont have one and use oil with a 100w pump run a max of 4 hours a day... maybe Ive mentioned that already.

zeupater

joefizz wrote: »

... I dont have one and use oil with a 100w pump run a max of 4 hours a day... maybe Ive mentioned that already.

Hi

Is that 4 hours of a 100W pump that I originally raised as ...

zeupater wrote: »

... (i) Any seasonal weighting wasn't included in the logic, only referenced as being necessary at the end with example given ... this is pretty standard ... people tend to use more electricity for lighting as well as DHW & space heating in months which have a lower ambient temperature & shorter daylight hours ... the percentage may vary, but the logic is pretty sound ...

.. and had to further clarify after you claimed there was no electricity used in DHW or space heating, before raising frost protection for holiday periods and mains water supply temperature differentials that would normally affect DHW heating duty in January ... below is the excerpt of my post in your own reply (#716), so it must have been seen ...

joefizz wrote: »

... 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 ...

... the exchange continues for a while right up to the last post where again you missed the point ...

joefizz wrote: »

Youve completely lost me.

Let me explain. Again.

I dont have either in winter so no pump. This DHW you speak off is an immersion heater used in summer. You know, electrical coil immersed in hot water tank. That thing.
I dont have space heaters so really dont understand why you keep bringing that up.

... before finally realising that DHW and space heating in your house actually does have a pump that consumes 100W ...

..
The only pump I have is when I turn the CH on to circulate the hot water from the boiler to the radiators. Its only on for at max a couple of hours per day in the coldest weather and yes its about 100W. I think this winter in any 24 period the longest it was on for 4 hours. (mild winter as mentioned).

So this first quarter maximum pump usage for heating the house was 400wh one day, most days 2-2.5hr was enough.
Understand now?

... and the relevance of "understand now?" means what exactly? .... do I understand that the 500Wh originally mentioned would be the same 400Wh you've finally accepted actually does exist when the 'mild-winter' is allowed for .... yes, I finally understand that you missed the point in amongst all of the meaningless waffle ...

For direct comparison & to set a baseline to how the relative combined space & DHW heating demand varied here due to the 'mild weather', our rolling 12months metered gas usage to the end of March averaged 4.2kWh/day in 2018, falling to 2.0kWh in 2019, which would have relevance to the pump run hours, so yes, I do understand and have done all along ... after all this time arguing, you've eventually found & admitted that your oil heating system consumes more electricity when it's being used than when it isn't and will, when checking daily solar generation, at some time twig that the energy consumed by the pump alone may represent "a considerable proportion of average daily PV generation in January & often all of a day's production ..." ! ... :doh:

... anyway, after this finally hits home the rhetorical spin continues with ...

joefizz wrote: »

... Its quite clear your experience of all of the above is very limited. In every single post starting with including standing charges, 100w pumps on all the time

... odd really, "100W pumps on all the time"?, I thought that 5 hours and 500Wh was mentioned as opposed to 24hours, so wouldn't that be 2.4kWh? .... but then again who exactly is supporting employing the "minutiae" of detail as opposed to spinning the spin?

The rest of the post, fine, think whatever you think .... but do at least think before you post!

Whatever the situation may be in atypical situations, the fact remains that for typical household, with typical usage patterns & typical electricity consumption the issue revolves around levels of energy autonomy a battery can deliver ...

.... Our generation was poor here today, & looking at PVOutput it seems to have been the case across most of the country ... what's up? - into April & a day's generation ends up at around 1-1.5kWh/kWp with a poor forecast here for a few days yet --- odds on estimated battery depletion time for each night on average UK consumption levels through 'till next weekend anyone ??

HTH
Z

1961Nick

joefizz wrote: »

Folks heres my 2p (well close to 10 grands worth).
I think a lot of you are getting bogged down in some of the minutiae of losses and economic return without looking at some of the other factors.
I have a 4kw east/west equal split solaredge system here in northern ireland.
Ive had it for almost 2 full years before putting in the me3000sp and initially 4.8kw battery. Maximum output was around 3.25kw so I decided when my garage was built to put 1.2kw in 4 extra panels south facing angled for best output feb-apr and sep-oct.

I added another 4.8kw of pylontech batteries in January.


I had the money for all of the above at times and so opportunity cost was the cost plus the ridiculous annual interest of about 1% or so which in real terms is loss but lets not go there...
Im not taking NI FIT into consideration but it should be roughly 400-500 quid a year so payback on the initial system in 10 years not including electricity costs. 8 years with electricity costs (at time of installation used about 6kWh per day on average - work from home, oil central heating and hot water, 1100l oil fill would do me about 11 or so months).


I went on a small generator seminar last summer and with the all ireland electricity market and brexit it scared the crap out of me so bought the battery system the next day. At 4.8kW it probably wouldnt pay for itself in 15 years so allowing for usual failure costs/upgrades etc it was more an environmental/lifestyle decision. I wired it to act as a UPS for the whole house (manual not automatic switch).



Since the solar installation I had changed the way I do things, cook during the day, slow cooker, bulk meals then freeze, use of 2nd freezer etc, washing machine and dishwasher alternate days at midday timed etc etc etc.



With the 4.8kW battery that changed a bit as say about now to late october it would only run down completely a couple of days. Part of the reason was that it peed me off putting the kettle on at 1kW generated and paying for the extra 200w at 16p a unit when in 30 secs I would be getting 4p a unit for exporting the excess.

I dont have an iboost etc because single household and considered it a waste of energy (and something that wouldnt ever pay back in my situation - Ive an immersion switch with 15 min setting).
The battery helped a lot and got me started on slow cooker overnight, dehydrator, stopping buying solar lights for the garden because all lights are now solar.... (are we learning yet ;-))
I started using the immersion for the shower and occasional hot water (4.8kw battery wasnt enough to stop sometimes importing - 9.6 is) so oil use has stretched by another month as Im not heating a tank of water morning every day now, just on demand.

Ive just bought one of the cheap chinese air source heat pumps and when I get time Im going to install it in the hall in my bungalow and this should from about now through to perhaps november supply heating/cooling. Again if that stretches oil purchase by another 4 months or so payback from that alone will be in 1-3 years depending on price of oil. This wouldnt have been feasible without the battery.


With the battery installed (in my spare room which now never really has heating on as those losses you all talk about go into heating the room), it gives you the opportunity to think a bit wider. I like to work on cars so rather than buying battery powered tools I can just go for the cheaper mains ones as I have a huge big battery in the house....
Back to electric lawn mower rather than petrol one...

Single use kettle, increased insulation and converting almost all the house and exterior lights to LED. Adding another chest freezer to the garage allows me to do a lot more cooking and storing which I wouldnt do otherwise. By the time winter comes round Ive a massive supply of home cooked microwave meals... again just thinking differently..
In my office from about Feb on Ive had a 90W tube heater under my desk for heating.... 9.6kw runs that for a long time, the south facing, clear access panels help.
The original intention was to move a couple of the east/west panels to the south but things progress and again Im not seeing it all as a fixed cost due to maintenance, upgrades etc. My solaredge inverter can cope with 20% extra loading so by my calculations I might just top that out a couple of days this year if we have a summer like last. If we dont and have a summer like the year before Im basically not paying for electricity from feb to nov.
Ive just had my last quarters electric bill in at just over 20 quid. Thats 20 quid total, for the quarter.
I changed suppliers last year with a 75quid sign up bonus. My entire electricity bill for the year was something like 150 quid. Down from around 4 or 5 times that. So add that cost into the fit and all of the above and its borderline 'payback' in around 10-12 years for everything provided no more maintenance, extras etc etc.
I have plans for perhaps another two panels, this time moved from e-w to put on sliding mounts to optimise for dec-jan and return to shoulder month level, but I'll take that from this years data with the system in stasis for 7 months.


I have a campervan with a couple of leisure batteries so will get a 100w solar panel for that along with a pure sine converter. Why? Well I have a charging point for it in the garage which is isolated from the house but if I throw the main switch into the house it might be possible to connect that up and mimic the grid so that even on sunny day with power cuts I can use the solar panels to keep the batteries charged.... Or maybe just use some of the export to keep those charged through the inbuilt mains charging system and kick over when I need... I have to add I have a degree in electrical engineering and masters in electronics so dont try this at home yourself kids...



Whilst I appreciate all the talk about losses, roi etc etc sometimes you just have to take a real world view and then take the end user approach and see the possibilities and opportunity costs of those possibilities as part of the equations.



Oh yeah Ive an inflatable hot tub and an infra red sauna now too... amazing what you can do when your running costs are effectively zero... oh hold on, the system is probably costing me more money than its saving...


So just to recap, rather than talking about 80 or 90% round trip losses and 2w or 5w background usage per piece of kit I'll repeat my electricity bill for the quarter was 20 quid and I'll likely not pay for electricity again until November.
Im down to only looking at my solaredge online monitoring and solarman online battery monitoring maybe 6 times a day now ;-)
Try not to think of the battery or solar in isolation but as part of a system, it can change the way you do things. If I didnt live in Northern Ireland then an electric moped would make a lot of sense now to replace a lot of the short town runs in the car....

This seemed like a very reasonable post to me. It's certainly not something that required pages of forensic examination & you shouldn't have had to write the equivalent of a short novel to justify it.

I wonder how many FMs are avoiding joining this discussion for fear of having their posts microscopically examined.....or does everyone run for the safety of the TAMG thread instead?

pile-o-stone

1961Nick wrote: »

This seemed like a very reasonable post to me. It's certainly not something that required pages of forensic examination & you shouldn't have had to write the equivalent of a short novel to justify it.

I wonder how many FMs are avoiding joining this discussion for fear of having their posts microscopically examined.....or does everyone run for the safety of the TAMG thread instead?

Thank you. My thoughts entirely. For a minute there it was like being in a court of law, not on a forum for friendly, likeminded RE enthusiasts.

mmmmikey

pile-o-stone wrote: »

Thank you. My thoughts entirely. For a minute there it was like being in a court of law, not on a forum for friendly, likeminded RE enthusiasts.

Absolutely agreed, let's make sure we keep this friendly.

Having said that, to balance things a bit, although the initial post that sparked these exchanges was perfectly reasonable, so was the initial response. But after that, if you start saying things along the lines of "let me make this really easy for you" or "which bit of this don't you understand" it's fair game to expect these to be seen these as challenges which demand responses (which again in fairness have all been well reasoned).

There's a lot of value and learning in the exchanges over the last few days, and although we don't want to discourage new posters, neither do we want to lose the interest and benefits of in-depth and rigorous analysis and debate. The "Z-test" ( if I can call it that ) may be uncomfortable for some but it's never unreasonable and a good, level-headed counter to the marketing we're all exposed to.

Good to have that sorted. Now, on to Brexit.......:):):)

joefizz

mmmmikey wrote: »

A

There's a lot of value and learning in the exchanges over the last few days,

Which is why I dont mind the banter at all, hopefully someone reading would get something out of it or pick up on one of the asides.
Ive been on and delivered a fair bit of professional training in my career and its often been the asides and anecdotes that have twigged with someone or lead someone to examine a different path.
What works for some people may not work for others or indeed may not even apply.
People can mention that generation was generally low across the country yesterday but also have to realise that sometimes people posting dont actually live in that country and can have a completely different set of returns. It doesnt make it less valid.


With regard to data sheets, as people have pointed out in multiple threads here and navitron, they really dont amount to a hill of beans in the real world as most are taken from one data standpoint, in fixed conditions. 'No battle plan survives first contact with the enemy'

So in a different climate, different humidity, different length of pipe cable, different ambient, different airflow and different mounting locations, you are going to get wide variations so although a cheap chinese bit of kit might have a cop of 3.2 and something costing 3-4 times as much might have a cop of 3.9, in that individuals case,in their circumstances the cop differential might be as low as .1 or .2. In that individuals circumstances if they are only using excess capacity then they will just go for the cheapest option, if you are using it as a main source of energy then you will go for the best ROI with energy input costs considered. Things like cop figures are notional representative values and things like that are oft used by salesmen and oft believed by the gullible to be actual tangible hard facts.

ASHPs are getting a bad press lately because nobody told people in the newbuilds that if they set the heating to 25C and run around the house in shorts and t-shirts in winter that they are going to get electricity bills of hundreds... but the published cop is 4.5, aye not for aberdeen in winter its not...



Same with batteries, I know people 10 miles from here who have at least one powercut every 2 weeks in winter. No point telling them a battery solution wont work as average figures dont work out...
Average figures and average estimates are just that, an average, a midpoint selected from a range of samples. The average height is five foot 10, try telling my six foot five cousin that he really shouldnt complain about having to duck his head every time he walks into a room because it suits the average.
The vast majority of people posting and reading here wont be average but there will be an average taken of all the posters and again most wont fit.



Similarly my house is almost passivhaus standard now (well as passivhaus as an 80s timber framed bungalow can be) so no point applying my system to a drafty victorian semi and I wouldnt try to.


Regarding the forensic examination, listen, I studied engineering for 4 years, worked in Engineering for 10 years, every single person was on a spectrum of some sort (long before spectrums were recognised), its par for the course (and one of the main reasons I resolved to FIRE at 50!). All my best mates are electrical/network/software Engineers, having a whiteboard session at a bbq is common... (well when alcohol is involved)

I worked for a well known telecoms company many years ago and the main development labs were in East Anglia and the old joke went that a plane was flying along in the fog and had become completely lost. The pilot flew around and flew around until he could find a tall building as a waypoint. He flew past one building and saw someone in the window. He shouted to the person in the window 'Where am I?'. 'Youre in a plane' came the reply. The pilot banked 30 degrees, flew for another 5 mins and landed right in the middle of the runway at Ipswich airport.
'How did you work out where you were?' the ground crew asked
'Well I asked a question that got a 100% factual response but of absolutely no use to anyone so knew I was flying over company x compliance department'


As for Brexit, damn, spent Sat in the Republic of Ireland, off tonight on the ferry to Liverpool. Guess I gotta unpack all that non-chlorinated chicken, bacon, chocolate and whiskey... Maybe next week ;-)
On a serious point about Brexit, whatever your view on it and whatever the outcome it will be used as an excuse to raise prices. I dont intend to comment on FIRE but being moneysaving and aiming to be self sustainable will help a lot in the coming years regardless of how you implement it.

zeupater

1961Nick wrote: »

This seemed like a very reasonable post to me. It's certainly not something that required pages of forensic examination & you shouldn't have had to write the equivalent of a short novel to justify it.

I wonder how many FMs are avoiding joining this discussion for fear of having their posts microscopically examined.....or does everyone run for the safety of the TAMG thread instead?

Hi

I totally agree, it did look very reasonable ... until you lift the bonnet that is ...

I think that a considerable spark was introduced into the debate in the conversation leading up to post #647, where the following observation was made ....

zeupater wrote: »

Martyn1981 wrote: »

... In Spain and Australia, they are seeing that PV can reduce demand by 40% and PV + battery reduces it by 90%, but they have a far smaller seasonal variation, perhaps 1.5 or 2:1 (summer v's winter), whereas we have about a 4:1 ratio.

Hi

It must also be appreciated that much of the difference between 40% & 90% being down to the battery supporting air conditioning throughout summer evening & nights in considerably warmer climates!

HTH
Z

... this fully representing climates & seasonal patterns that don't suit the UK, ie, cooling demand outweighs that of heating so the annual demand profile approximates that of excess PV supply .... after much delving into what wasn't initially disclosed, maybe we can now all appreciate that joefizz's usage pattern has 'evolved' in a way which attempts to mirror that in Australia or Spain through minimising winter demand & maximising that in summer ... ie hot tubs, electric BBQs, summer weighted computer use etc ... even then the holiday situation & tariffs excluding standing charges and negotiated discounts needed to come into play to support & justify previous details ...

... wouldn't it have been much easier to avoid all of the the cost justification & stick with the initial concept of non-justification regarding the battery ... "it probably wouldnt pay for itself in 15 years so allowing for usual failure costs/upgrades etc it was more an environmental/lifestyle decision" ... as opposed to what looks to be a deliberate move towards maximising self consumption and using cross subsidy from the PV system to justify a 'system' or total solution payback as opposed to taking an incremental approach? ....

... anyway, whilst talking about consistency did anyone else pick up on the ASHP being justified using incremental logic?

As an aside ... earlier in the discussion there was a short reference to a 'random NI supplier quarterly DD T&Cs', maybe most missed it, but it came from this NI supplier .... link to current available tariffs .... considering the discussion at the time, I initially found it interesting reading in many ways, but thought best to not muddy the waters more than necessary at the time ... what should we conclude from this snippet of detail if this is the supplier & the offerings have been consistent?!


HTH
Z

mmmmikey

joefizz wrote: »

Which is why I dont mind the banter at all, hopefully someone reading would get something out of it or pick up on one of the asides.

That's good to hear, and I'll take it as an invitation to be quite frank in sharing my views on some of the points you've made

It's interesting to read what you've said but that certainly doesn't mean I agree with a lot of it. Forgive me for being quite so blunt but to my way of thinking your reasoning and logic borders on stark raving bonkers, particularly in the context of green and ethical moneysaving

1. Moneysaving. As I understand it you've realised that having batteries alongside solar panels gives you access to an abundance of free power in the summer. On the back of this you've splashed out (pun 1 ) on a hot tub, electric barbecue, etc. spending £1000s you hadn't planned to. To me this is a bit like my ex-wife going shopping for some shoes and coming home with some shoes, a handbag and 3 new tops, having convinced herself that she'd saved loads of money by not buying the coat and trousers she saw as well. Her money, her choice, but not my idea of moneysaving! What you appear to have done is to justify the expense of the batteries by spending money to create demand that wasn't there before which doesn't match my moneysaving views any more than my ex's shopping habits.

2. Green & Ethical. You appear to have done nothing (or very little) to use the batteries to reduce your carbon footprint in any of this, choosing to fill your boots with expensive toys to soak up excess supply rather than exporting excess energy back to the grid, reducing the need for carbon producing power elsewhere. Great that you've insulated your house, etc. but that's not really anything to do with the batteries which are the subject of this post. This is your choice of course, but hardly green. Or ethical if your investments are partially funded through public investment through FITs or whatever, which are justified on the basis of carbon saving.

3. Technical understanding. I don't doubt your engineering credentials, but it is clear from some of your posts you haven't fully understood some of the points Z has made. For example, you make reference to not having any space heaters but then talk about your oil fired heating and radiators in the next sentence, not having understood that the radiators are a form of space heating. To be fair, you may have made this comment in the heat of the moment (pun 2 ) but the difficulty I have is once I see someone make a mistake as basic as this alarm bells start ringing. None of us are born knowing what space heating is and the fact that you haven't understood this isn't the issue. The concern for me is that speaking confidently about this online in the belief that you do understand it can lead others to take what you say at face value and point them in the wrong direction. That is why I believe the technical challenges you have been subjected to are so important.

Please be assured that none of this is personal, I just have very, very different views to you and believe your post really belongs on a not-green, unethical moneywasting site!

Gulp - did I really just say all that? Enjoy the summer, anyway :):)

Solarchaser

I felt I should finally post here after reading these pages for way over a year.

Why? Because of 1961Nick's post.
As in, I couldn't agree more!!

I've often thought I should post my experience about my 4kw fit solar panels fitted 4 years ago, the difference they, and certain behavioural changes have made to my bills.
More recently the installation of an me3000sp and batteries, and even more recently the addition of an electric car, more solar panels and a hybrid inverter, but I have stopped myself from doing do several times, when I see how anyone who posts something different, sees their every word analysed and assassinated or driven into the most minute detail as to declare the person a liar.

There is great information in this thread, but there is also a real failure to accept that not everything is calculatable to the nth degree, especially when its theoretical.

Kev

1961Nick

mmmmikey wrote: »

3. Technical understanding. I don't doubt your engineering credentials, but it is clear from some of your posts you haven't fully understood some of the points Z has made. For example, you make reference to not having any space heaters but then talk about your oil fired heating and radiators in the next sentence, not having understood that the radiators are a form of space heating. To be fair, you may have made this comment in the heat of the moment (pun 2 ) but the difficulty I have is once I see someone make a mistake as basic as this alarm bells start ringing. None of us are born knowing what space heating is and the fact that you haven't understood this isn't the issue. The concern for me is that speaking confidently about this online in the belief that you do understand it can lead others to take what you say at face value and point them in the wrong direction. That is why I believe the technical challenges you have been subjected to are so important.

I'm confused.:huh:

I'd always thought that a "space heater" was a heater where the source of the heat was within the heater.....as against central heating where the source of the heat is elsewhere.

Is that wrong?