Help regarding Solar and Battery installation

Reed_Richards

Do make sure you really want the complication of some of these more off-the-wall Octopus tariffs.   And consider also what might happen if these tariffs get withdrawn; that could completely change the economics of what you are planning so try to compare the general case of more typical import costs and export payments and check that you reach the same conclusion. 

Screwdriva

When I installed my own PV system in Q4 2019, the installer predicted electricity import tariffs of 19p per kWh and several enlightened forum members simply wouldn't have it

I don't see energy prices coming down anytime soon. That said, and if I am wrong, OP can always add a battery on to your system down the line. Now VAT free thanks to this government. 

charles_b_2

@Reed_Richards that's an incredibly important point.  I'm still wrestling with my own project and it seems to me that Octopus is a rather large part of the expected savings (and I'm only looking at flux right now). With no direct competitors offering close to the same kind of flexibility, the chances of significant changes are probably quite high, particularly as electricity prices are (at least for the moment) on a downward trajectory whilst standing charges are an upward trend, this has the effect of reducing the savings on costs overall.  I'd like to see the other big suppliers start to offer Tariffs that are as innovative as Octopus' as that would at least have the effect of keeping them competitive.

Solarchaser

Screwdriva said:

When I installed my own PV system in Q4 2019, the installer predicted electricity import tariffs of 19p per kWh and several enlightened forum members simply wouldn't have it

I don't see energy prices coming down anytime soon. That said, and if I am wrong, OP can always add a battery on to your system down the line. Now VAT free thanks to this government. 

This is the same installer who predicted 4500kwh /year out of a 4kw system and a far higher self use than you could ever achieve, yes?

And we are supposed to applaud the same government that withdrew all but all support for solar nearly 10 years ago, err ....

I think Reed makes a very good point, and I may well end up with egg on my face for saying this, but octopus do seem to be the good guys of energy supply, and the only ones who were opposed to the increase of standing charge as I recall.

I should perhaps also say I've put my money where my mouth is (or suffered from terrible blinkered vision) in regards to octopus, as it was purely based on their off peak tarrif prices vs gas prices that made me decide to switch to electric only almost two years ago.

The bill I have of ~£1300 /year would be more like £5000+/ year if octopus withdrew their off peak tarrifs, as the majority of other suppliers only really offer the off peak for ev chargers, not the whole household.

EcoScruples

Screwdriver makes an excellent analogy with the virtual battery, when my system was installed the best SEG tarriff was 5ppkw so a battery made sense as a user of 4.5mw per year.
A brew months later SEG went crazy and a virtual battery would have cut my payback by a huge amount.

Currently my system should payback in 7.3 years
Without the cost of the battery and more panels and use of Octopus Flux this would have been much less., maybe under 5 years.

Screwdriva

Solarchaser said:

This is the same installer who predicted 4500kwh /year out of a 4kw system and a far higher self use than you could ever achieve, yes?

To be fair to the installer, the system is outperforming given the chimney shading affecting 2 out of 10 panels throughout the day, and the triple aspect (SSE/ ENE/ WSW) layout. We achieved 3.8-3.9 mWh every year despite these very real limitations. 

Solarchaser said:

And we are supposed to applaud the same government that withdrew all but all support for solar nearly 10 years ago, err ....

Not sure really, as subsidies like FIT are a complicated issue. . . but I do applaud the removal of VAT for retrofit batteries. 

gh67

Thanks for all the replies, certainly gives me something to think about.

Heedtheadvice

I am also South of Scotland location (West side) and rural.

You have many good responses to mull over there. I cannot add much

Support post install is valuable but some installers expertise soon fades and it is not always great to rely on manufacturers especially if you struggle technically. Personal recommendations of long established companies that are diversified are in my opinion of value.

 I went with Lotus Electrical  who have  a very good reputation and could not be more pleased - not the cheapest though, but quality.

It is difficult to financially justify battery purchase with the tariffs (as alternatives) currently available but  there are other reasons. 

One is risk reduction ( as mentioned Tariffs and associated costs do change), we can be more prone to blackouts in rural areas -sometimes for days such as with recent storms and a freezer full of food spoiled is costly ( if not insured) or just a mess to deal with, so backup facility is very useful. 

That also could apply to fibre router voice services where emergency calls fail if one's power fails come 2025 or sooner as older analogue cable phones ( yes I still have one available as well as a mobile) can get powered from the exchange. Paranoid belt braces and binder twine!

There is also a convenience aspect such as less concern over when power is used and having the ability to arrive home late in the day and still get some free/cheapcharge into an EV.

These days using solar PV to heat a domestic hot water cylinder is not really worth it of you have to buy/install a diverter.

1961Nick

Have a look at Fogstar batteries if you want the maximum kWh for your buck.

https://www.fogstar.co.uk/collections/solar-battery-storage/products/server-rack-battery-48v-5-12kwh

https://www.fogstar.co.uk/collections/solar-battery-storage/products/fogstar-energy-15-5kwh-48v-battery

I have Pylontechs & rate them highly but if I was starting with battery storage today I would use Fogstar.

thriftytracey

We just had an extra couple of panels fitted.  We have had quite a few bright and sunny days this winter and generated decent levels.  We had 14 kWh generated the other day.  We have a battery and it is programmed to draw from the grid between 2 - 5 am to use the cheaper electricity on Octopus Flex.  We are £800 in credit.  We lost out on the selling back to the grid as we didn't get the MPAN reference until November so looking forward to this Spring and Summer.