2 x GivEnergy 9.5kWh (19kWh total) with 5kW Hybrid inverter

Sunsynk 5kW inverter with 2 x 5.32kWh batteries (currently considering adding 2 more to this).

By the end of next month...

8 kW PV + Tesla Powerwall 3 and DC Expansion pack (27 kWh total)

The race to electrify our homes is well underway, but how many of us are really going all-in? We’ve launched a quick poll to find out who has a heat pump, solar PV, EV or home battery, and who’s planning to add what next.

Take 30 seconds to vote and help us map the UK’s electrification journey:

https://renewableheatinghub.co.uk/are-solar-batteries-and-heat-pumps-the-ultimate-net-zero-trio

What about the poor relation - solar thermal - free hot water for 8 months of the year, or is the only focus now on self generation and feeding an immersion.  There is also the elephant in the renewable room. I am I going to get an economic return on my investment in panels and batteries over a reasonable period, sub 8 years at least? 

Posted by: @abernyte

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am I going to get an economic return on my investment in panels and batteries over a reasonable period, sub 8 years at least? 

Really depends how you use them, and how you have them installed. DIY install not much chance of being paid for export, but install costs are way lower. So self consumption is the game. A battery help as does a heat pump. Our current average price per kWh including grid, PV and offset (Economy 7) power via battery is 5p per kWh, so a fifth normal price.

My first array of PV was fired into life end of 2021 and in about 4 months will have paid for itself. So 4 years. If it was a MCS install, I would would be a  few more years to get payback even if I was paid for export. So based on 20 year life I have 16 years free energy from them panels.

My second array was build using second hand components (2 years life) and was less than half the cost. That will have paid for it's self in about 3 years.

But since I purchased panel costs are about half the price. But MCS install hasn't changed in cost.

I totally agree that self install is certainly going to bring down that break even point in a reasonable time.  However, I am willing to bet that the vast majority of installs are MCS and that really requires some realistic accounting to get a hard nosed view on when you are actually going to start making money and how much. The battery guarantees I have seen recently are around 10 years in many cases and the panel performance degradation is similar. If your age is putting you into the sniper zone then it does require a careful, dispassionate look at the viability.

Whilst the eco arguments for PV and heat pumps and, to a lesser extent EVs, are pretty clear, the eco argument for a battery is much less so, at least to me. 

So whilst I made my decision to invest in solar panels, heat pump and EV at least in part on eco grounds (which is not to say that they haven't also turned out to be good financially and, in the case of the EV and heat pump, in terms also of performance), my decision (not) to get a battery is purely financial.  It's marginal and getting closer with time so a bit more time or a convincing eco argument may well tip the balance. 

Alternatively the obvious fact that every EV sold in the last 14 years has a larger battery than most dedicated home storage units, and that many 'second cars' spend much of their time on the driveway (particularly during the grid's most intensive hours and overnight) will hopefully lead to an option to combine 'second car' with home storage in one multi purpose cost effective package.  For example a 10 year old Leaf  (or whichever is the oldest model with built in bidirectional capability) would be just perfect for this application if a suitable inverter/charger were available.  Plug in overnight, do a few miles during the day for commute/social, return in time for supper, plug in, discharge to help the grid at peak time and avoid any peak tarrif.  Rinse and repeat 

@jamespa To a certain extent, by exporting to the grid all my excess solar during the summer (for credit) enables me to ‘pull back’ energy in the less sunny and somewhat cooler months when the ASHP gets hungry. This is a form of storage system albeit with losses - but then there are losses with the battery storage method as well. Regards, Toodles.

Tesla Powerwall 3 with Gateway.

Tesla Powerwall 3 with Gateway.

Solaredge Energy Bank DC coupled

10 kWh (9.7 usable).

Nissan Leaf 30 kWh with Indra V2G charger (hacked of course) giving a usable 21 kWh of battery storage.

Both are integrated with our Home Assistant based HEMS to allow everything to play nicely together.