Solar options (mind field)

QrizB

handful said:

I think my main reason for seriously considering solar is to future proof our supply and cost of electricity to some degree and I think a battery helps to do that.

Without a battery, you'll typically be able to replace about a third of your electricity with home-grown solar power and you'll export the rest. With a battery, you'll typically be able to replace two-thirds. (Numbers will vary depending on exactly what proportion of your electricity you use when it's dark, and/or in the winter months when your panels won't generate much).

You're using about 2700kWh/yr (I've rounded to make the sums easier). The size of PV system you're looking at should generate at least 4000kWh/yr. You can currently buy electricity for around 25p/kWh and sell for 15p/kWh.

Without solar, 2700kWh purchased from the grid will cost £675.

With solar, you'll replace 900kWh with yor own solar electricity, leaving you to buy 1800kWh at a cost of £450 (saving £225). You'll sell 3100kWh for £465. Total return £690 per year.

With solar and a basic battery, you'llreplace 1800kWh and need to buy 900kWh at a cost of £225 (saving another £225, total saving £450) and you'll sell 2200kWh for £330 (a reduction of £135). Total return £780, only £90 more than without a battery.

If solar without a battery costs you about £5k, it will pay for itself in a little over seven years.

If you add a basic battery for £2k, the battery will take 22 years to pay for itself (which is longer than it's likely to last).

The advantage of the Powerwall 3 (which Screwdriva will tell you is the best home battery system on the market) is that it lets you get a special electricity tariff that means you're not paying 25p/kWh for the energy you buy from the grid. But your household doesn't currently use enough electricity for those tariff-related savings to justify the ~£6k additional cost of a PW3.

Screwdriva

Well summarized! 

I would add that the PW3 is viewed by some of us as the best in class due to several reasons, including access to Intelligent Octopus Flux which is paying end users roughly 27p per kWh these days. I do often wonder if that positively influences the case for smaller systems but haven't had the chance to run the numbers yet. 

handful

QrizB said:

handful said:

I think my main reason for seriously considering solar is to future proof our supply and cost of electricity to some degree and I think a battery helps to do that.

Without a battery, you'll typically be able to replace about a third of your electricity with home-grown solar power and you'll export the rest. With a battery, you'll typically be able to replace two-thirds. (Numbers will vary depending on exactly what proportion of your electricity you use when it's dark, and/or in the winter months when your panels won't generate much).

You're using about 2700kWh/yr (I've rounded to make the sums easier). The size of PV system you're looking at should generate at least 4000kWh/yr. You can currently buy electricity for around 25p/kWh and sell for 15p/kWh.

Without solar, 2700kWh purchased from the grid will cost £675.

With solar, you'll replace 900kWh with yor own solar electricity, leaving you to buy 1800kWh at a cost of £450 (saving £225). You'll sell 3100kWh for £465. Total return £690 per year.

With solar and a basic battery, you'llreplace 1800kWh and need to buy 900kWh at a cost of £225 (saving another £225, total saving £450) and you'll sell 2200kWh for £330 (a reduction of £135). Total return £780, only £90 more than without a battery.

If solar without a battery costs you about £5k, it will pay for itself in a little over seven years.

If you add a basic battery for £2k, the battery will take 22 years to pay for itself (which is longer than it's likely to last).

The advantage of the Powerwall 3 (which Screwdriva will tell you is the best home battery system on the market) is that it lets you get a special electricity tariff that means you're not paying 25p/kWh for the energy you buy from the grid. But your household doesn't currently use enough electricity for those tariff-related savings to justify the ~£6k additional cost of a PW3.

That's really helpful, thanks QrizB and makes perfect sense

phill2-0-0-3

QrizB said:

OK, I think I've modelled their proposal without their crazy inflation increases - so everything is in today's money.

Here's what I get:

It's a 25-year real return of 4%, which isn't terrible and is better than you'll get with an ISA or gilts. But that assumes that the system continues to work for 25 years without any downtime or (costed) replacement parts.

[That IRR might be slightly off; checking is vs. a compound interest calculator, it should be more like 4.05% but it's close enough.]

Many thanks for giving a more honest response.
Still seems a very viable option .
And if it's eventually only generating a income . Then that's a positive . 

Will look into other panels and see what the options are . 

thegentleway

Screwdriva said:

Well summarized! 

I would add that the PW3 is viewed by some of us as the best in class due to several reasons, including access to Intelligent Octopus Flux which is paying end users roughly 27p per kWh these days. I do often wonder if that positively influences the case for smaller systems but haven't had the chance to run the numbers yet. 

I didn't realise PW3 was compatible with IOF! I've had a PW3 for 8 months. I agree with OP that solar options are a bewildering. There's some useful youtube channels like Gary does Solar that a very helpful for getting your head round the options. 

Screwdriva

thegentleway said:

I didn't realise PW3 was compatible with IOF! I've had a PW3 for 8 months. I agree with OP that solar options are a bewildering. There's some useful youtube channels like Gary does Solar that a very helpful for getting your head round the options. 

Went live a couple months ago. I'd sign up if I were you - it's relatively straightforward now. Personally, no longer a fan of Gary since he tied up with installers on a commercial basis.

thegentleway

Screwdriva said:

thegentleway said:

I didn't realise PW3 was compatible with IOF! I've had a PW3 for 8 months. I agree with OP that solar options are a bewildering. There's some useful youtube channels like Gary does Solar that a very helpful for getting your head round the options. 

Went live a couple months ago. I'd sign up if I were you - it's relatively straightforward now. Personally, no longer a fan of Gary since he tied up with installers on a commercial basis.

Haven't been missing out for too long then. I have signed up. Is there a way to be notified of new tariffs/changes?

I didn't realise that about Gary. I found his videos helpful and don't remember him mentioning, let alone pushing any installers.

Screwdriva

thegentleway said:

Haven't been missing out for too long then. I have signed up. Is there a way to be notified of new tariffs/changes?

I didn't realise that about Gary. I found his videos helpful and don't remember him mentioning, let alone pushing any installers.

None that I know - I suggest people switch away from IOF to Intelligent Go around October. Jury is still out on Gary Does Solar but he does have a recommended installer list, which makes we wonder how unbiased his recommendations are. 

thegentleway

Screwdriva said:

thegentleway said:

Haven't been missing out for too long then. I have signed up. Is there a way to be notified of new tariffs/changes?

I didn't realise that about Gary. I found his videos helpful and don't remember him mentioning, let alone pushing any installers.

None that I know - I suggest people switch away from IOG to Intelligent Go around October. Jury is still out on Gary Does Solar but he does have a recommended installer list, which makes we wonder how unbiased his recommendations are. 

Presumably you mean IOF to Intelligent Go?

October as that's when consumption becomes greater than generation? That makes sense. IOF when consumption < generation to export at best rates and IOGo when consumption > generation to charge battery cheaply at night.

JKenH

thegentleway said:

Screwdriva said:

thegentleway said:

I didn't realise PW3 was compatible with IOF! I've had a PW3 for 8 months. I agree with OP that solar options are a bewildering. There's some useful youtube channels like Gary does Solar that a very helpful for getting your head round the options. 

Went live a couple months ago. I'd sign up if I were you - it's relatively straightforward now. Personally, no longer a fan of Gary since he tied up with installers on a commercial basis.

Haven't been missing out for too long then. I have signed up. Is there a way to be notified of new tariffs/changes?

I didn't realise that about Gary. I found his videos helpful and don't remember him mentioning, let alone pushing any installers.

Gary is very bullish about the financial case for investing in solar panels.



https://youtu.be/XSeiTkwfRTg?si=-9SIQW7Y2Rqj_nmQ