On-grid domestic battery storage

EricMears

mmmmikey wrote: »

If you have a smart meter installed and are then required to move from deemed export to real export payments, then any solar power you use to charge your battery ceases to be "free" for the remainder of your FIT agreement.

Yet another argument in favour of not accepting a 'smart meter' when supplier insists that you have to (in spite of them being purely a customer choice).

Unless & until someone offers a really good 'smart' package, I've no intention of volunteering !

mmmmikey

zeupater wrote: »

......depending on your PV array, battery size/specification & household energy consumption you may actually find that it's actually far cheaper to totally forget the idea of E7 and simply seek out the best single rate tariff to suit the reduced consumption level over a 12 month period .... I've already touched on this a number of times over the past few months so you may be interested in reviewing some of the posts!

Yes, your posts make interesting reading thanks, and I have read many of them over the last year or so.

In my case its very much cheaper to use an E7 tarriff because I have night storage heaters, although as you point out E7 doesn't make sense for a lot of people (probably most?). To add context, the chain of events leading to my decision to take the plunge into the world of batteries was:

1. Bought a house with solar panels, which combined with basic energy saving measures (refined over the years and adjusted to reflect the availability of solar power) make me a very low electricity user, other than for water and space heating.

2. Added an iBoost type device to increase use of "free" solar power.

3. At this stage looked at batteries to maximise use of solar power, but for me at this stage this was a total non-starter. At the times of year when I have spare solar power to charge a battery my demand is too low to make worthwhile gains. At the times of year when my demand is high enough to make worthwhile gains there isn't enough spare solar power to charge a battery(because of the iBoost).

4. When I bought the house, I had budgeted for gas central heating to replace the expensive to run Fischer Future Heat electric radiators.

5. When I came to replace the heating and did the sums, I realised that because I am such a low non-heating electricity user I could achieve 85%+ night time usage with night storage heaters on an E7 tarriff, bringing heating cost per kWh to <6p per kWh without a big hit on other usage and tipping the balance in favour of storage heaters when you factor in all the costs. It quickly became clear that I was never going to recover the capital cost of the gas central heating in it's lifetime, so I installed the storage heaters. (6 months in, nice warm house, costs in line with forecasts and I'm at 87% night time usage).

6. At this point I looked at batteries again, realising that the economics had changed. I could use cheap rate electricity to charge the batteries overnight throughout the year and use it to save buying peak rate electricity during the day. As well as saving me more per kWh used I could also get much closer to using the full capacity of the battery. This still wasn't quite enough to convince me to buy, but getting closer.

7. I then got details of the grid services contract from EDF that has the potential to save up to £1500 over its lifetime (but probably half that) and this tipped the balance towards buying. I'm still far from certain of turning a profit (mainly because the grid services contract is such an unknown) but now reasonably confident that this won't end costing much.

So what's the point of all this?

1. I wholeheartedly agree with everything you've said about the economic case for batteries not being there at the moment for the simple case of a single rate tarriff electricity user with solar panels (although I'd be happy to be proved wrong on this). None of the scenarios I've modelled make this work - batteries are simply too expensive in relation to the return.

2. A lot of other things have to line up in your favour to get to the point of having a fighting chance of seing your money back. However, even at current battery prices there are some realistic scenarios that make this possible (albeit risky). In my case, solar power barely features in the logic, it's really only the day/night E7 differential and grid services contract that make this worth the risk.


Time will tell I guess

orrery

mmmmikey wrote: »

.... can you reasonably assume a life of 6000/300 = 20 years?

Well, no. I'm sitting in a hotel room with my portable battery I use for charging my phone when I'm out and about. It only ever gets charged, never discharged, as I keep it for 'just in case'. I just check it is fully charged before I go places.


Today, on a long coach journey around an island the phone got a hammering, so I used the portable charger, which went from 100% to 25% instantly and then lasted about 2 minutes.


I'm now cycling it end-to-end by using it as a charger and then charging it up again every night (will it help? Mmm - who knows)



I'm just making the point that a cold calculation of battery cycles won't give you the life of the battery in use, it is just one of the limiting factors that needs to be overlaid on the others.

cdunne

Apologies running out of time, not sure if this has already been covered in this thread but what are your opinions to this...

EON have done it again! I got Solar panels installed in 2015 (by an independent company) following their advertising and now within a week of their battery storage advertising another company has pointed me to https://www.social.energy/index.html This sounds like a fantastic 'gig economy' type idea to me (utilizing household battery storage to buy energy when it's cheap and sell it when it's expensive).

I assume the the energy market is a bit like the stock market and the price per KWH fluctuates every minute depending on the supply and loads on the system. I.e. at midday on a sunny summers day the price is very low given all the solar panels on the grid but at an advertising break during a popular TV programme it is high due to the number of kettles being boiled etc. Therefore the great idea behind the social.energy model is to buy it when it's cheap and sell when expensive.

My panels are on the 2015 Oct / Dec FIT rate (currently 13.47 p/KWH FIT with a 2.64p/KWH export (I have a 'dumb' grid meter so it's half of 5.24p/KWH)

Now a few points, I thought they depended upon you having a smart meter but their FAQ states this isn't the case. I suspect it would be if you have grid generation though.

The storage provider who mentioned them stated that my FIT rate would be unaffected but I'd loose my export payment ( so in effect my rate would reduce by 16%).

Points to resolve:

1: For properties with generation is a smart meter required? I would like to avoid moving to one if possible! (If one is not required does the battery unit record actual exports to the grid?)

2: Am I correct about possible FIT reduction? Given there is no change to the my existing solar edge system can social.energy guarantee that my FIT rate (not the export) won't be effected.

3: There is a tax exemption for the the tariffs received for energy produced under the FITs. Does the social.energy system have anything that needs to be declared to the 'tax man'?

4: Is there a process in place should social.energy go into liquidation? (I think given it's a new area the risk of this happening is fairly high). Would customers retain their energy stores? Would be easily modified to continue to operate as standard stores without external control? What would happen to the warranty coverage in this case?

5: Must the system have a fully working internet connection to work? Does it do Wi-Fi? (there is no easy way to route a RJ45 to where I'm thinking of placing it, my existing solar edge system has a WiFi connection).

6: I can see my demand from the grid increasing at times of cheap energy and I'm not generating (i.e. through the night) to charge the battery. Does your charge automatically deduct all exported energy from that imported?

7: Are the rates you charge customers directly correlated to the grid rate at the time of energy consumption / generation?

8: What would the cost to me be?

9. My generation average over the 3.25 years has been 9.21KWH/Day (quarter high June - Aug 2018 18.03 KWH/Day, quarter low Dec 16- Feb 18 3.2 KWH/Day). I suspect over half of this is currently exported to the grid since I have no immersion heater etc

My consumption average (from my supplier meter so excluding my solar consumption) is 3KWH/Day.

So based on these values what would be the predicted payback of the social.energy (would this exceed the 15 year guarantee for it).

mmmmikey

Hi

Many of your questions are answered by the terms and conditions on their website. I think the best way to get your head round this is to look at it in 2 parts and consider the costs and potential returns for each part.

Part 1 - Battery

You buy a "bog standard" solar battery from any one of a number of accreditted providers. What you see back is a reduction in your electricity bills because you are storing up some of your free solar energy and using that instead of buying electricity. The economics of this are discussed at length in this thread with most opinions lying somewhere between "this simply doesn't add up at the moment" and "it might just pay for itself but it's unlikely to be a money spinner". I suggest you read the posts and form your own view on this.

Part 2 - Social Energy

(a) You buy a Social Energy smart hub from whoever supplies your battery and have this installed at the same time as the battery. The cost of this isn't given on the website.

(b) You agree to buy your energy from Social Energy. Their tarriff is shown but not very attractive. Assuming you are paying 12p per unit for electrcity at the moment, they charge 16p and you buy, say, 2500kWh per year this costs you £100 per year in increased electricity charges. You can do the sums using your own figures.

(c) as part of the deal you agree to allow Social Energy to use your battery for "trading in the electricity market" as much as they like as and when they please. This reduces any benefit you get from a "bog standard" battery by an amount you can't calculate because you don't know how much they'll use it - you just have to trust them.

(d) Social Energy give you a share of any money they've made trading each quarter. This will be your share of about 70% of what they've made - i.e. if they've made £10,000 they'll distribute £7,000 in equal share between their customers, so if they have 100 customers you'll get £70. This isn't based on what they've metered for your battery, this is just a share of what they've made overall divided between their customers. You can't calculate how much this will be because you don't know how successful their trading will be, again you just have to trust them.

Note that they are not just (or possibly not at all?) trading in the sense that you suggest (i.e. buying cheap electricity, storing it in your battery and selling it when it's expensve). What they're doing is trading on the Dynamic Frequency Response market which is something different. They make several references to this on their website. This is probably a moot point because you don't know how much they're going to make however they're trading, but if you want me to try and explain this further let me know and I'll do my best.

To sum up, the Social Energy offering appears to me to be hugely speculative with absolutely no guarantee (or probably even any reasonable assurance or expectation) of providing a return.

That doesn't mean it can't make money, but I have to say it's way, way, way off my risk scale.

So if it was me, I'd just stick with the batteries as long as you're happy to see this as a planet-saving initiative rather than a money-spinner.

p.s. the only way I think they could make me more suspicious of the website is by adding pictures of a parade of naked Chippendales / Dancing Girls carrying "special offer ends soon" banners. Even if they did that I'm not sure I'd notice through the tears of laughter at the crass video! Unless you're immune to high-pressure marketing, I'd walk away now.

1961Nick

A couple of observations after 7 weeks.....

Round trip losses vary considerably depending on usage. If the batteries are continuously charged during the day & then discharged in the evening, the round trip loss is about 6%. When the batteries are asked to flip between charge & discharge during the day the loss can be over 15%.

Lots of 'flipping' during the day can result in 5% of the generation escaping to the grid. The export is negligible for a steady daytime charge/evening discharge regime.

I've added another battery to the stack to make 12kWh total - 10.2kWh usable.

mre15

Hi 1961Nick

Can I ask where you are getting your batteries and if the price is right.
I am looking to add to mine but the price still seems a little high.
Cheers

1961Nick

mre15 wrote: »

Hi 1961Nick

Can I ask where you are getting your batteries and if the price is right.
I am looking to add to mine but the price still seems a little high.
Cheers

The best price I can find is £650 + Vat from Amco Renewables in Doncaster

Reed_Richards

I took the plunge and installed a solar PV system and battery through a company called Solarcentury that partners with Ikea. It went in ten days ago and seems to work tolerably well, I am now consuming 1 to 1.5 kWhr per day instead of about 8 kWhr before. But the details of exactly how it works and what control you have over the operation are not well documented. Is there anyone else out there with something similar that can offer some money-saving tips and tricks for how to get the best out of such a system? Or who can point me at the right posts to read here?

chamelion

1961Nick wrote: »

The best price I can find is £650 + Vat from Amco Renewables in Doncaster

are these actually worth it? what % of your generation do you actually use if you didn't have batteries?