Solar Panels installed 13years ago, are batteries now worth it?

newbie8

Hello all,

My parents had Solar Panels installed about 13yrs ago. They managed to  get the higher FiT rate but was advised not to get batteries installed because it was not really expensive for what it could store. 

The installer is no longer in business and I'm having trouble finding someone to ask about batteries (they live in the middle of nowhere!).

With the price of electricity, is it worth installing batteries now? 

Thanks,

gefnew

Try posting on this forum with a bit more information.
Green & Ethical MoneySaving — MoneySavingExpert Forum

newbie8

gefnew said:

Try posting on this forum with a bit more information.
Green & Ethical MoneySaving — MoneySavingExpert Forum

Will do. Thank you. 
What other bits of information do I need? e.g. tariff? who they sell electric to? 

QrizB

newbie8 said:

gefnew said:

Try posting on this forum with a bit more information.
Green & Ethical MoneySaving — MoneySavingExpert Forum

Will do. Thank you. 
What other bits of information do I need? e.g. tariff? who they sell electric to? 

Just start the same thread you've posted here, but over there.

You will be asked how many kWh their array generates, and how much electricity your parents use each year.

Ectophile

An inverter fitted years ago probably won't be compatible with a battery bank.  I did have a battery fitted when the old inverter failed.

Petriix

What I've discovered (thanks to 5 months of smart meter data) is that it's possible to load shift sufficient usage to the low cost overnight rate to make a battery hard to justify in financial terms. However, that's entirely based on my own usage pattern, which I'm able to monitor in detail thanks to also having a Zappi EV charging point which shows me how much I'm importing and exporting.

The point is that a) having an EV and getting on to Octopus Go is a massive saving for the rest of your usage that you're able to shift; and b) having reliable usage data is the only way of actually knowing what savings you could make. My overriding instinct is that most people wouldn't benefit from batteries at this point, but some people (with unusually high usage which can't be shifted to off-peak) can make a reasonable case.

Givenergy seem to be the best value right now but you're looking at around £5k for a 10kWh battery retrofit. They'd absolutely need an AC coupled battery inverter and leave the FIT system untouched.

[Deleted User]

Beware of making any changes to the existing solar array as this can impact on you FIT payments. All batteries (or to be more precise their inverters) are treated as potential generators by your DNO. You will have to submit an application based on your proposed battery system. The DNO will review your existing local Grid infrastructure before agreeing an export limit. One option to avoid all this hassle is to fit a DC battery such as SolarEdge.

Is it worth it? It really depends on how much solar energy is used and house demand. I have a 6.5kWp array; a Powerwall 2 (13.5kWh) battery; solar diverter and EV. We use about 80% of what the roof generates. At today’s prices, my payback period is about 12 years: clearly, for solar panels alone the payback time would be a lot less. Buying a standalone battery though is a different issue (not least because there is 20% VAT for most people). In the summer for example, we might use about 1.5kWh of battery power overnight: clearly, as the days get shorter, the battery comes more into play: however, over Winter, most of the energy is still coming from the Grid. Finally, it is not 1kWh into a battery and 1kWh out. All batteries suffer round trip losses: my Powerwall 2 is about 10%.

MSE_ForumTeam5

We've moved this thread

arty688

Another advantage of you being on the old FIT system is you get nothing for the electric that goes back into the grid so the payback on anything that uses that electric is shorter than someone on SEG. Also if you are thinking of batteries you may want to think of a few panels and battery as the VAT will be 0% if you have a panel as well. No idea on the impact of any of this on your FIT as I missed that boat.

Exiled_Tyke

inverter compatibility should not be a problem.  My system has a separate inverter for the battery.  Nor should DNO or changes to FIT. The battery won't be exporting but supplying the house so there will be no issues with 'grid' issues.   

It should be a simple job of comparing the cost of installation to the price of electricity to determine whether it's a good investment for you or not.  There are a number of options. Powerwall is the most expensive. I'm happy with my Solax which should cover its costs (although I didn't expect it to when I bought it). 

Of course the other issue is what happens to electricity prices.  No one really knows if they will stay high or settle back down to where they were 12 months ago.

Exiled_Tyke

arty688 said:

Another advantage of you being on the old FIT system is you get nothing for the electric that goes back into the grid so the payback on anything that uses that electric is shorter than someone on SEG. Also if you are thinking of batteries you may want to think of a few panels and battery as the VAT will be 0% if you have a panel as well. No idea on the impact of any of this on your FIT as I missed that boat.

I think you've explained the FIT point the wrong way round. Someone on FIT still gets payments whether or not you use the electricity or it goes back to the grid.  

Good point on the VAT.. I added two panels to reduce the VAT. They have their own micro inverter and meter and kept separate from my FIT registered system.