Solar options (mind field)

Magnitio

Martyn1981 said:

prowla said:

A "mind field" - maybe you're over thinking it?

I'd assumed it was deliberate, a great play on words, and planned to steal it alongside my personal approach - "just give me 5 minutes to overthink this'.

It's not as bad as a mined field.

QrizB

phill2-0-0-3 said:

These are the two quotes I have received the rear of my property has 3 seperate pitches.
I have enquired if I could have 4 panels on the rear and then the front done which is more cost efficient 
Does this seem a fair price ? 

Without getting into the details, Option 2 costs less, generates more electricity and pays back sooner. So it seems a much better deal than Option 1 is.

Also if the panels are facing northwest it means you'll get most of your output in the afternoon and evening, when electricity is (currently) more expensive.

If the only choice was those two options, I'd take Option 2.

Now for the details.

If you're using 7000 kWh/yr of electricity, that's an average of 20kWh/day. Where does it all go? Do you have electric heating, hopefully storage heaters and/or a heat pump?

If it doesn't include heating, your house will swallow a 5kWh battery and still be hungry for more. You might want double that, and could even think about a Powerwall 3. If you drop Screwdriva a DM he might know an installer in your area who could quote for one?

zxzxzx

Magnitio said:

Martyn1981 said:

prowla said:

A "mind field" - maybe you're over thinking it?

I'd assumed it was deliberate, a great play on words, and planned to steal it alongside my personal approach - "just give me 5 minutes to overthink this'.

It's not as bad as a mined field.

Your post was opencast to interpretation, I guess my mind fled?

Screwdriva

QrizB said:

Without getting into the details, Option 2 costs less, generates more electricity and pays back sooner. So it seems a much better deal than Option 1 is.

I would be very surprised if a 12 panel 5.5 kWp system will generate 3.9mWh per year facing the North West aspect. Typically, NW aspect installations generate < 60% of the rated system peak generation with pure North often generating < 45% in a full year. I suspect the installer in question is being a bit liberal with their estimates and doesn't want to do the rear roof (Option 1). 

Martyn1981

Screwdriva said:

QrizB said:

Without getting into the details, Option 2 costs less, generates more electricity and pays back sooner. So it seems a much better deal than Option 1 is.

I would be very surprised if a 12 panel 5.5 kWp system will generate 3.9mWh per year facing the North West aspect. Typically, NW aspect installations generate < 60% of the rated system peak generation with pure North often generating < 45% in a full year. I suspect the installer in question is being a bit liberal with their estimates and doesn't want to do the rear roof (Option 1). 

Yes, for reference my WNW install is roughly in line with PVGIS estimates over the last 13yrs. It's better than NW, and at 30d pitch is fairly shallow (compared to some) which will help too. For my location in Cardiff the comparison per kWp is 1,022kWh for S facing and 681kWh for WNW, so ~67%. For NW, PVGIS suggests 604kWh or ~59%.

Also, at the time of install for me, the WNW panels brought a very usefull boost to late afternoon/early evening generation, perfect for cooking tea. But these days, going bigger on the southern aspects (where possible) may be better, as a battery can time shift for you, as and when battery costs are acceptable to the homeowner.

I actually think north roofs are worth considering, at least briefly. But crucially they need to be in addition to a south roof install, as at that point the extra cost could be 50%/kWp of the other install, making up for the lower generation. But even then there are caveats these days, that didn't apply just a few years ago, such as cheap panels being used for fences, maybe a carport, pergola, or even wall mounted, as this is now PD*. Those options if better sited than a northern aspect roof, might fair better, especially again if batts are used. Times they are a changing ....


*Edit - Doh, speaking of permitted development, I missed another 'obvious' option as per my own signature pic, and that's garden structures such as my ladder store, or if under 9m2 a 'normal' ground mount.

prowla

zxzxzx said:

Magnitio said:

Martyn1981 said:

prowla said:

A "mind field" - maybe you're over thinking it?

I'd assumed it was deliberate, a great play on words, and planned to steal it alongside my personal approach - "just give me 5 minutes to overthink this'.

It's not as bad as a mined field.

Your post was opencast to interpretation, I guess my mind fled?

It was the pits!

phill2-0-0-3

have updated there response ..
They have yet to deliver a price . 

Screwdriva

Proceed with caution & ask for details of the panels/ inverter and battery being quoted. 

phill2-0-0-3

This is the inverter and projected returns .
Seems very unlikely.. 
£171'000 after 25 years 

Martyn1981

Pretty silly to use a compounded 8% for fuel savings, especially given the curent starting point where leccy prices are impacted by the gas price and Europe wide shortfall.

I've no idea where things will end up, by prices should decline at least for a while as Europe continues to move away from gas. And whilst the UK grid needs rebuilding, expansion and modernizing for the future, the bulk of RE generation has zero fuel cost, which helps to stabilize their long term cost of generation.