Solar - real-life experience of investment vs return

Solarchaser

new_owner said:

I am on the other fence. 

My current batteries without solar, for me they are looking to have a payback of 3 years using an off-peak tariff (at current prices - I suspect this will be even shorter in 2023. I am now looking to add another two inverters and more batteries to run the planned heat pump with the idea of running my heating completely from batteries.

The issue I have found is that solar would only give me a saving of around £60 per month in the middle of summer and the payback would be so long, to not make it worth while. This is because I am using batteries first and so have to base the return off my off-peak rate.

This might change in the future but at this point batteries without solar make perfect sense for me.

I'd be interested to see the figures for a 3 year payback, that sounds very interesting. 
Total usage, battery and inverter type and size, as well as peak and off peak prices would be good to see.
£60 / month in summer, ok but for payback it's more about the shoulder months than mid summer.
In summer we all tend to use less electricity.

Unless you are paying through the nose for an inefficient system (lots of shading and/or poor aspects) solar usually always makes sense before batteries... though the recent price increases have definitely balanced that out somewhat.

For reference as a 8mwh user per year, I was paying more in standing charge than for electricity from beginning of March until almost the end of September. 

JKenH

I don’t have batteries but did have an EV for 11 months and have consumed 62.5% of the PV I generated in 2022.
That is with an East/West roof which performs poorly in winter. My average cost of imported electricity is around 10p/kWh x 3800kWh self consumed = £380 p.a. My system cost me £7k in 2018. 

I have been enjoying FiT payments (which include deemed export) but without FiT I could also earn around £90 in SEG payments from the 1830 kWh I exported. 

Based on the above my set up this year would have generated around £470 p.a. so it would take around 15 years to payback. However from March I am expecting to pay 34p or so for electricity so the payback changes to £1382 p.a. which gives a  period of just over 5 years to cover the cost of installation (if I were starting now). 

Screwdriva

Martyn1981 said:

But I do agree with you that solar investment/encouragement by the Gov should have been much higher, but for the UK it will be a lower source of generation, by far, than wind.

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1128689/mission-zero-independent-review.pdf

I'm not sure who the recently released "Mission Zero" report would side with but it clearly calls for over-indexing in solar (5X current levels), which is good to see. I do not see why the government would advocate this if the demand didn't exist but I am entirely naive to the subtlety of policymaking. 

Martyn1981

Yep, 5x would be lovely. Loads of potential for more PV in the UK. But of course it will stay remain a lower source of generation, by far, than wind, in the UK.

Screwdriva

Martyn1981 said:

Yep, 5x would be lovely. Loads of potential for more PV in the UK. But of course it will stay remain a lower source of generation, by far, than wind, in the UK.

We achieved ~20% of total grid generation in the summer months in '22. At 5X, it would appear the goal is for solar to cover 100% of our consumption during no/ low wind months?

ABrass

Screwdriva said:

Martyn1981 said:

Yep, 5x would be lovely. Loads of potential for more PV in the UK. But of course it will stay remain a lower source of generation, by far, than wind, in the UK.

We achieved ~20% of total grid generation in the summer months in '22. At 5X, it would appear the goal is for solar to cover 100% of our consumption during no/ low wind months?

Which would make export much less valuable 

BTW there is no such thing as no-wind months. Solar varies by something like 6x between peak and low months. Wind only varies by something like 1.5x

Screwdriva

ABrass said:

BTW there is no such thing as no-wind months. Solar varies by something like 6x between peak and low months. Wind only varies by something like 1.5x

Except when the wind doesn't blow (during most of last summer when we the grid was powered by >50% gas). 

I believe solar may become more valuable as a result of the disparity between wind and PV generation. Again, time will tell.