Battery and extra panels?

theboylard

Long time no see!!

Hope all are well?

So, in the market for a battery and hopefully some extra panels.

Haven't got an installer sorted so any recommendations for east midlands would be appreciated!

Currently got 4kw with SolarEdge, FiT is 20yr contract, installed in March 2014.

First off, whats the score on VAT cuurently? See some saying it's at 5%, some saying none and some sites show it as usual 20%

It makes a difference to what we can do?

What else might we need in terms of isolators, switches, commectors and cabling?

Secondly, looking at approx 10Kwh of storage. Anyone recommend any suppliers?

Seeing guide pricing on its technologies site for Pylontech and Fox and Alpha, and then stumbled across GSL all in one systems?

Seems like a great price, wondering what the downside is? I know DOD is 80%, but that may well help battery life?

Any and all info and advice welcome!

zaber86

I'm in a similar boat to you, and have just gone for more panels and a battery. Note that some have said that even at the current energy prices it's still not actually economical to get a battery fitted, vs just the solar. 

Any new array would have to be separate from your current system to keep your FIT rates. 

One thing to note is that batteries are liable for VAT unless installed at the same time as solar panels.

Petriix

I'd suggest doing your calculations very carefully based on actual smart meter data to see what you could save with a battery. While there is a use case for abnormally high users, anyone with typical consumption patterns will struggle to break even on a battery at this time, especially with the recent inflation in prices. 

I had an 8.2kWh Givenergy battery on order last year but ended up cancelling because I was importing so little peak electricity that I would never have recovered the initial investment. Put it this way, at £5,000 for 5.5kWh (instlled), you'd need to save £500 per year (£42 per month) to break even in 10 years. That's about 1500kWh of peak imports avoided at 34p per kWh, or fully utilising the batteries (at 90% efficiency) on 300 days each year. How realistic is that?

yp70479

Other things to factor in to your battery v no battery calculation. With a battery you can switch to economy 7 and charge the battery overnight at cheap rate and use that power during the day in the winter. OK - there are some DC/AC losses, but you can pay around 15p per KW at the moment compared to over 30pKw for standard rate. You can also take advantage of "smart tariffs (Octopus offer one to their users) where the price paid for your export to the grid can be based on the wholesale price that day. Prices change every half hour with the most being paid when the grid is busiest. Current prices paid this week for peak time have varied between about 40-60pKW, prices have gone as high a £1 KW last month. So if you charge off peak and sell at peak rate you can cover some of the cost of your electricity over the winter - even when the sun isn't shining!

ispookie666

Not so great time to be thinking about Solar panels and batteries, due to supply chain bottle necks and busy installers.  The prices have gone up significantly.  

For additional panels, what orientation will you be installing them? 

I suspect with your current system you would have been the G83/59 approved with an export limit of 3.68KW per phase.  You will likely need DNO approval for new panels and definitely for the batteries.   Adding panels along with batteries will give you 0% VAT for the whole install vs 20% VAT for isolated battery installation.  

Plenty of battery manufacturers from the low end to ££££, Pylon tech has been in the market for a long time compared to a lot of the others.  I do have Givenergy and am less than impressed by the problems I have faced (looks like i'm the unlucky one!).  I have 16.4 KWh storage and have had to pretty much use it all when there has been no solar generation (we are a high energy usage household).  I'm hoping the Li batteries will be much better than SLA ones.  

Batteries do help with time shifting of tariff and storing free generated electric in the sunshine months, but the economics of it is very much up in the air and is heavily mired in confirmation bias.  

I was thinking of adding some more panels on my garage roof (3 additional panesl) but could not justify the extra expense.  

silverwhistle

As a single household with 4kWp of PV and a low user I couldn't justify a battery although would like a few W/SW facing panels for later in the day production.

But I might buy myself a cable for Christmas: my MG4 (51kWh battery) can do Vehicle to Load at up to 7kW, so the ability to run an air fryer, kettle or microwave might come in useful! On one of the EV forums somebody has even wired their house to be able to island/isolate it and run the whole house. They did an experiment with the load and if the charger tripped it came back automatically once the load was removed and went under the limit again.

It might be a cheapish solution to potential power cuts, and even help when I voluntarily participate in Octopus saver sessions.

Wolfkeeper

We've just signed off on a PV and battery system here. The thing that sealed the deal was off-peak rates. Bulb currently have an 'EV tariff' that delivers just under 10p per kWh between 2am and 6am, and that's enough to fill the battery we've chosen. Bulb are in administration, and the tariffs may well change, but other tariffs seem to work out too in the round. Together with a relatively small PV system, we're expecting to more or less power the house with solar and off-peak electricity all year around except winter where it will be a mixture of peak rate, and off-peak and virtually no solar, but even that should still reduce monthly bills.

It looks like for our usage patterns a battery sized with a gross capacity about 2/3 of the daily usage and PV sized to provide (on average) all our daily summer usage gives the best ROI of about 10%. I tried other combinations such as not using the battery, or only using the battery, or varying the amounts of each, but this seems to work out the best.

I found it quite tricky to model, you have to allow for the practical depth of discharge of the battery, the losses into and out of the battery, and the variations in the solar output both statistical day-day and seasonal, and export and import rates etc. etc. But it seems to be a win. It's due to be installed late January, the components at least seem to be in stock right now.

1961Nick

This is how it works out for me when I put the current energy price into my spreadsheet for the whole year - Intelligent Octopus @ 10p off peak & using 34p for typical peak.

Solar self use 98%
Round trip loss 20%

Solar battery charging: 2160kWh @ 34p = £734
Grid battery charging: 2444kWh @ 22p = £538

Annual saving £1272

(4604kWh is the actual metered discharge figure)

SEG isn't an option with FIT.

Other factors to consider are savings made by load shifting to the off peak period & the extra cost of peak rate above the 34p price cap.

Screwdriva

Petriix said:

I'd suggest doing your calculations very carefully based on actual smart meter data to see what you could save with a battery. While there is a use case for abnormally high users, anyone with typical consumption patterns will struggle to break even on a battery at this time, especially with the recent inflation in prices. 

I had an 8.2kWh Givenergy battery on order last year but ended up cancelling because I was importing so little peak electricity that I would never have recovered the initial investment. Put it this way, at £5,000 for 5.5kWh (instlled), you'd need to save £500 per year (£42 per month) to break even in 10 years. That's about 1500kWh of peak imports avoided at 34p per kWh, or fully utilising the batteries (at 90% efficiency) on 300 days each year. How realistic is that?

Agree 100%. It actually may make some financial sense to add a couple extra panels to an existing 3.68 Inverter (not sure if that's kosher with FIT?), a battery is a significant investment that no longer pays for itself unless you have an EV + Heat Pump + heavy night time usage. 

This calculator does an excellent job calculating ROI of a battery vs. no battery setup. If you decide to ignore the brain and follow the heart, MyEnergi's Libbi modular battery offers UK based support, honours their warranty and includes excellent app integration with their hot water diverter (Eddi) and EV charger (Zappi).

ABrass

With a battery in winter an E7 plan can work well and in the shoulder months as well. Then in the summer switch to a standard plan.

Wolfkeeper

Screwdriva said:

This calculator does an excellent job calculating ROI of a battery vs. no battery setup. If you decide to ignore the brain and follow the heart, MyEnergi's Libbi modular battery offers UK based support, honours their warranty and includes excellent app integration with their hot water diverter (Eddi) and EV charger (Zappi).

No offense, but it doesn't do a good job at all. It doesn't know about night rate charging. Using night rate electricity to charge a battery gives you very cheap electricity throughout the year that you can use for most of the year when the solar isn't keeping up. You're getting almost all of your electricity on night rate, or from solar panels over most of the year.

That makes the calculator extremely pessimistic.

The EV night rates that are available are as low 8-12p/kWh. That compares very, very favorably with ~33p/kWh rates you can otherwise achieve.