A useful exercise in logic ?

zeupater

Hi All

After a recent set of exchanges regarding some outrageous claims (if you don't know what they were you're probably not going to be too interested!), I've done some really serious number crunching ....by 'serious' I'm talking about hitting brick walls on the capacity/capabilities of a pretty high-end machine on multiple occasions and having to resort to multi-stage pre-processing of data, some ambitious (/horrendously complex!) single stage logic and cutting back on a few niceties for now, but as long as I take care of how the model is loaded it can just about work in testing ....

For now I have a single consumption model based on 3300kWh/year against which various PV & storage setups/capacities can be modelled against standard & E7 energy tariffs


Discussion? .... Questions ? ....


Don't intend the thread to be a long running one! ... :cool:

Z

JKenH

That went right over my head.😩

Coastalwatch

Nice one Zeup, sounds like you've been burning the midnight oil(wind)!
Not wishing to create any further headscratching, but I'd be interested to see what it comes up with using the prices EDF are currently offering their battery's for!

Oh, I posted a link on the On-grid Battery Storage thread earlier and repeat below in case you've not seen it...
https://www.solarpowerportal.co.uk/news/edf_energy_targets_solar_homes_with_discounted_battery_offer

zeupater

Hi (JKenH)

Good, trying to keep it all vague ...




Anyway, something to keep Coastalwatch scratching the cranium regarding an earlier post if this thread is visited ...

On the 3300kWh/year modelled (v1r17) and applying this to (his?) system with 8.2kWh of storage (90%/10% limited?) ... benefit to household bills (approx!)

Standard - £590
PV - £405
PV+Stg(E7) - £221 (D£106+N£115)

Interestingly, on a consumption model where usage is around average and weighed towards daytime/evening (cooking/washing/ironing etc) even with storage of this size it looks to be to leave E7 overnight aside and stay on a single daytime tariff! (more to do with pattern than total use!) ... I would have given more detail but running the model & a browser plays havoc with memory management ... ... will need to use different machines in the future ....


Anyone catching on yet!

HTH
Z

zeupater

Coastalwatch wrote: »

Nice one Zeup, sounds like you've been burning the midnight oil(wind)!
Not wishing to create any further headscratching, but I'd be interested to see what it comes up with using the prices EDF are currently offering their battery's for!

Oh, I posted a link on the On-grid Battery Storage thread earlier and repeat below in case you've not seen it...
https://www.solarpowerportal.co.uk/news/edf_energy_targets_solar_homes_with_discounted_battery_offer

Hi

Yes, lots of head-scratching to work this one out on a machine that can sit on your lap with any kind of data granularity that provides any sensible form of analysis!

Anyway, see above post ... I looked at the spec sheets and needed to change the model to allow for split charge/supply rates (that's what r17 is!) ... it's pretty approx at the moment because of variables which aren't in the specs etc, but I've simply applied some generic information gleaned from elsewhere!

Memory management is still killing this system & autosave has just started on a fully populated model ... so I'm going to end the process & have a coffee :coffee: ....

HTH
Z


#EDIT - system reloaded, missing PV+Stg (No E7/grid charging) works out as £182 ... note: modelling your large PV system with average consumption tends to increase grid imports by around 1100kWh/year if E7 is used ... this is displacing generation which would go to storage ... I've only modelled an average usage pattern for now, but the system is built to generate any number of patterns (if I can be eventually bothered!)

Coastalwatch

Don't think head scratching will do me much good Zeup as anything beyond quadratic equations is beyond my comprehension. Do I take the £182 to be the annual projected savings! If so, the ROI works out to a lengthy 27.5 years. I've still to complete a years worth of generation so can only estimate what's been consumed from the grid so far which suggests around £220/annum. This still requires a 22 year pay back so not particularly attractive especially as the battery is only warranted for ten years!

Thanks indeed for the post Zeup. Hope I haven't caused too much of a diversion?

zeupater

Coastalwatch wrote: »

Don't think head scratching will do me much good Zeup as anything beyond quadratic equations is beyond my comprehension. Do I take the £182 to be the annual projected savings! If so, the ROI works out to a lengthy 27.5 years. I've still to complete a years worth of generation so can only estimate what's been consumed from the grid so far which suggests around £220/annum. This still requires a 22 year pay back so not particularly attractive especially as the battery is only warranted for ten years!

Thanks indeed for the post Zeup. Hope I haven't caused too much of a diversion?

Hi

On the basis of bills in #4, if electricity costs with solar are £405, the predicted cost with storage would be £182, so saving around £223 ....

HTH
Z

ps .. no diversion, that's why I started a new thread!

Coastalwatch

zeupater wrote: »

Hi

On the basis of bills in #4, if electricity costs with solar are £405, the predicted cost with storage would be £182, so saving around £223 ....

HTH
Z

ps .. no diversion, that's why I started a new thread!

Ah, yes I can see that now, thanks for the explanation.

So even with EDF's discount we're still a long way from achieving anything like a sensble ROI. Actually Powervault do offer their own system coupled to Gridflex payments of £20 month for the owner of the battery and this brings the ROI down to about half that of the EDF option. Unless EDF are making some similar sort of allowance for using the battery to smooth the grid then I can't see too many of us clambering to sign up!
While our electric energy usage has been less than average in the past, this will change dramatically now that we've an EV and two ASHP's. With heating in the winter likely to consume 14kWh's daily, other domestic appliances averaging 7kWh's and the EV 6kWh's then, whatever size battery is likely to offer us the most benefit, is going to be food for further significant headscratching in the ensuing weeks and months.

zeupater

Coastalwatch wrote: »

Ah, yes I can see that now, thanks for the explanation.

So even with EDF's discount we're still a long way from achieving anything like a sensble ROI. Actually Powervault do offer their own system coupled to Gridflex payments of £20 month for the owner of the battery and this brings the ROI down to about half that of the EDF option. Unless EDF are making some similar sort of allowance for using the battery to smooth the grid then I can't see too many of us clambering to sign up!
While our electric energy usage has been less than average in the past, this will change dramatically now that we've an EV and two ASHP's. With heating in the winter likely to consume 14kWh's daily, other domestic appliances averaging 7kWh's and the EV 6kWh's then, whatever size battery is likely to offer us the most benefit, is going to be food for further significant headscratching in the ensuing weeks and months.

Hi

Latest version .... (v1r20)

Managed to squeeze a simulation of smart/intelligent charging into the model which looks to vary the off peak charge level curve throughout the year to minimise interference with PV ... this results in a further saving in the PV/stg/E7 of ~£37 (to ~£184), but still leaves the result at ~£2/year more costly than not using E7/overnight cheap rate supply (£182) ...

Caveat - Considering that I've not seen anything related to this level of sophistication on these batteries in the marketing details, I doubt that these (or most other offerings) have anywhere near this form of functionality as standard .... (yet!)

HTH
Z

michaels

So if I told you our generation and usage you could tell me the economics of adding storage and or switching to a time of day tariff?

zeupater

michaels wrote: »

So if I told you our generation and usage you could tell me the economics of adding storage and or switching to a time of day tariff?

Hi

Probably give an idea with better accuracy than anyone looking to sell a product ... that's what started the idea off .....

HTH
Z