Solar Battery Storage

steveing64

Have been loooking at some of the options with regard to storing the solar during day i know telsa have an option but cant seem to find a price i found a company that supplies a system t have quoted £2800 to £3000 to supply and install dont want to put the name on here in case get in trouble but are there any other alternatives and if so cost.

I have a 3.6kwh panel system been in since Novmeber and looking to make the most of it as i dont have hot water tank cant use the unwanted power to heat water seems a waste it going back in grid yesterday i produced 20.4kwh but exported 13.

Martyn1981

steveing64 wrote: »

Have been loooking at some of the options with regard to storing the solar during day i know telsa have an option but cant seem to find a price i found a company that supplies a system t have quoted £2800 to £3000 to supply and install dont want to put the name on here in case get in trouble but are there any other alternatives and if so cost.

I have a 3.6kwh panel system been in since Novmeber and looking to make the most of it as i dont have hot water tank cant use the unwanted power to heat water seems a waste it going back in grid yesterday i produced 20.4kwh but exported 13.

Hiya.

Have a read of these threads, lots happening at the moment:-

Good of Bad News for Storage?

Battery Storage System for Solar/E7

Tesla to unveil home storage batteries


Whatever your thoughts are, I reckon you should wait. Perhaps 5yrs, but at least 2yrs. There's a lot happening at the moment.

Systems are starting to rollout, so the price will fall as production numbers go up.

Battery production (and technology) is ramping up, so expect significant price reductions over the next few years.

There are loads of competitors, so expect some sort of standardisation, and also for some manufacturers to fail, or get swallowed up by others.

Also there's a slim chance that some sort of shared cost scheme might arrive as the leccy suppliers, DNO's and govt can all save money through domestic storage. However, this is only my belief, there are no current plans for anything like this.

Happy reading.

Mart.

Martyn1981

steveing64 wrote: »

I have a 3.6kwh panel system been in since Novmeber and looking to make the most of it as i dont have hot water tank cant use the unwanted power to heat water seems a waste it going back in grid yesterday i produced 20.4kwh but exported 13.

If you don't already, I'd suggest keeping a record of generation, and import, so as to work out potential leccy (import) savings.

One thing of note to myself, is that during the summer months, when I have loads of export, PV covers about 2/3 of consumption, and I only import, on average, 2.5kWh per day.

If I only buy 2.5kWh, then I can only save 2.5kWh, regardless of generation, or battery size.

In the winter I import more, but have less spare export, to store.

So the best months for me would be the spring and autumn, when both export and import are high(ish), say 4 or 5kWh per day import with more than enough export.

In total I could probably save another 1,000kWh, but those savings placed against a battery life of perhaps 10 years, only equate to about a £1k investment.

Lots to think about, from multiple angles.

Mart.

NigeWick

steveing64 wrote: »

Have been loooking at some of the options with regard to storing the solar during day

I do not think batteries for storing solar generated electricity will be viable on a purely financial basis. But, I too have been looking at something from Tesla because I believe it is getting more likely that there will be power cuts in the future, and, I'd like to do my bit for the environment.

As Martyn says, prices will eventually come down but as I'm a pensioner I honestly do not want to wait too long before committing myself.

I've got a 4kW solar system and have stayed with Economy 7 so that when I get batteries I'll be able to take advantage of the slightly cheaper night time electricity as and when it will work out best value.

michaels

NigeWick wrote: »

I do not think batteries for storing solar generated electricity will be viable on a purely financial basis. But, I too have been looking at something from Tesla because I believe it is getting more likely that there will be power cuts in the future, and, I'd like to do my bit for the environment.

As Martyn says, prices will eventually come down but as I'm a pensioner I honestly do not want to wait too long before committing myself.

I've got a 4kW solar system and have stayed with Economy 7 so that when I get batteries I'll be able to take advantage of the slightly cheaper night time electricity as and when it will work out best value.

I was thinking about this - Martyn, you obviously have a good handle on your generation and usage. Suppose you were on an e7 tariff with peak 11p/unit, off peak 6p/unit in winter and a standard rate tariff at 10p/unit at other times and you could use the battery to store E7 energy in the winter for daytiem use would that impact your £1000 breakeven price?

Also were enrgy prices to increase overall by 20% (I don't think this is fantasy, current prices are historically low) how does the impact the math?

A final thought, the govt had an auction for 'standby capacity' which was apparently won by diesel generators - I wonder if the money to fund this could instead subsidise a 'merged array' of domestic batteries where the householder got to use the stored energy in normal circumstances but it was available to the grid as emergency supply if called upon?

zeupater

michaels wrote: »

I was thinking about this - Martyn, you obviously have a good handle on your generation and usage. Suppose you were on an e7 tariff with peak 11p/unit, off peak 6p/unit in winter and a standard rate tariff at 10p/unit at other times and you could use the battery to store E7 energy in the winter for daytiem use would that impact your £1000 breakeven price?

Also were enrgy prices to increase overall by 20% (I don't think this is fantasy, current prices are historically low) how does the impact the math?

A final thought, the govt had an auction for 'standby capacity' which was apparently won by diesel generators - I wonder if the money to fund this could instead subsidise a 'merged array' of domestic batteries where the householder got to use the stored energy in normal circumstances but it was available to the grid as emergency supply if called upon?

Hi

Regarding the use of cheap(er) E7 electricity in the daytime (ie shifting load), this is one of the advantages which is proposed on a number of battery/storage propositions. The 'standby capacity' is obviously also an option which is being investigated in a number of trials which are currently being conducted around the country, as is simple domestic demand shifting through storage of E7 or excess solar for timed release to meet peak demand times (eg Scottish Power's current Maslow(?) trials etc) ...

Of course, the goal of various forms of demand smoothing is to address the requirement for expensive peak-reactive generating capacity ... however, the inevitable consequence is that smoothing demand variability will also smooth the price variability, bridging the gap between daytime and E7 tariffs .... what could initially look to be an effective way to justify domestic storage & 'beat the system' may not look quite so good if demand shifting/smoothing (including EVs) becomes significant.

HTH
Z

Martyn1981

michaels wrote: »

I was thinking about this - Martyn, you obviously have a good handle on your generation and usage. Suppose you were on an e7 tariff with peak 11p/unit, off peak 6p/unit in winter and a standard rate tariff at 10p/unit at other times and you could use the battery to store E7 energy in the winter for daytiem use would that impact your £1000 breakeven price?

Also were enrgy prices to increase overall by 20% (I don't think this is fantasy, current prices are historically low) how does the impact the math?

Hiya michaels, hmm, where to start.

Firstly a disclaimer, anything I say relates to my situation, so that's generating pattern, generating size, monthly consumption, and total consumption. I think that's important as it'll change the maths for each household.

Generating pattern - I get around 4,500kWh pa. So on par with a very (very) good 4kWp south facing system. But my gen has a higher summer to winter ratio as it's E/W with shallowish panels. A south system would get a better daily spread across the year, especially in the winter, which would probably increase the potential of batts.

My system generates well all day(light) in the summer, but ironically that probably works in favour of a south system, as it might increase the daily import a bit (from my 2.5kWh) but still well withing a 5kWh batt, making greater use of the batt. And in the winter there would be more gen/export from a south system to make better use of the batt.

Consumption - we consume about 3,000kWh pa, importing 1,600kWh. So not too much, but a higher user would get more out of a battery system. Import does vary by month, but I suspect varies more with an E/W system than a south system. My lowest months are June and July with around 70-80kWh, and my highest months are Dec and Jan with around 190-200kWh.

Sorry, long intro and disclaimer, so would E7 help. I think it would, but only really for the bottom 3 to 4 months, the rest of the year the batt/PV would cover almost all consumption (excluding some exceptionally poor back to back days in Spring or Autumn).

So let's say I import 600kWh of E7 (make that 720kWh to allow for 20% losses?). Using your figures that would cost 720x6p = £43.20, to save 600kWh at 10p (using the non E7 rate) = £60.

So £17 for 10 years = £170. That's not a massive amount, but it's also not insignificant either. Also fits in with any future plans regarding an EV.

Leccy prices. I've been pondering this long enough for prices to go down, was originally thinking 1,000kWh at 15p, so £1,500 over 10 years. So yes, it does make a difference moving forward. So if batt prices fall, leccy prices rise, and E7 helps a little bit, it could work for me, and others.

Mart.

Martyn1981

Can I add another angle, since this is a G&E board.

Until such time as renewables are over producing, which probably won't be for another 10 years in the UK, then we have a slight environmental conundrum.

If I store my leccy in batts, there will be some loss, whereas if I export it all there is no loss (negligible), so the UK grid benefits more.

The counter argument is that if PV with a batt is economical, whereas PV without a batt isn't, then the clean gen wouldn't exist in the first place.

I'm not a raving green (nothing wrong with raving greens) just pointing out the issue is a little complex at the moment but probably sorts itself out in the near future as intermittent generation gets larger and storage becomes a necessity.

Mart.

Martyn1981

zeupater wrote: »

Of course, the goal of various forms of demand smoothing is to address the requirement for expensive peak-reactive generating capacity ... however, the inevitable consequence is that smoothing demand variability will also smooth the price variability, bridging the gap between daytime and E7 tariffs .... what could initially look to be an effective way to justify domestic storage & 'beat the system' may not look quite so good if demand shifting/smoothing (including EVs) becomes significant.

That's a really important point, and I don't have a clue, as there are too many variables, and they are very big variables.

Coal and nuclear are inflexible, so that's more gen at night to get rid off. But coal is being closed, and we may never get back to todays 20%(ish) nuclear contribution. So excess leccy down?

Wind generates well at night, and some of the latest off-shore farms have capacity factors in the high 40's, so excess leccy up?

EV's will have a massive influence on demand, but can anyone predict the rollouts over the next 10 to 20 years. Excess leccy down?

Heat pumps running through the night?

More or less need for E7 ..... I haven't got a clue.

Mart.

Cardew

steveing64 wrote: »

cant use the unwanted power to heat water seems a waste it going back in grid

The very thought of the heavily subsidised electricity you produce actually being fed to the Grid must be horrifying;)

Exiled_Tyke

Martyn1981 wrote: »

Can I add another angle, since this is a G&E board.

Until such time as renewables are over producing, which probably won't be for another 10 years in the UK, then we have a slight environmental conundrum.

If I store my leccy in batts, there will be some loss, whereas if I export it all there is no loss (negligible), so the UK grid benefits more.

The counter argument is that if PV with a batt is economical, whereas PV without a batt isn't, then the clean gen wouldn't exist in the first place.

I'm not a raving green (nothing wrong with raving greens) just pointing out the issue is a little complex at the moment but probably sorts itself out in the near future as intermittent generation gets larger and storage becomes a necessity.

Mart.

If we assume that most 'on demand' electricity is (for the foreseeable future) to be met by gas turbines (being the only generation method with enough 'instant' capacity) then isn't your use of batteries green? In that, rather than adding to the off-peak supply of electricity (which presumably the aim will be to satisfy this need from nuclear and renewables) you are instead reducing peak-time demand in the use of less green power sources? Even though there is an efficiency loss in using batteries you are still reducing dependancy on fossil fuels which surely is a good thing?