Solar PV - no roof space

[Hotlush]

So we've had some quotes and they've basically knocked the idea of having solar PV on the house roof on the head due to the dormer.

We had already been planning to get a summer house at the bottom of the garden so thinking of accelerating that and use it's roof space.
We're lucky enough have a fair bit of equity and putting it on the mortgage isn't excessive for us.
In theory the savings on electric would be around the same as our predicted increase when the tariff changes in September so we shouldn't be that much worse off and might even reduce our overall bills a bit.
Currently on Octopus Go 13.5p/5p tariff and looking like will be 40p/7.5p+ when we renew going on current offerings.

Have chatted to a local garden buildings company and they seem confident they can build one with sufficient strength to handle some panels on top.
So currently awaiting a quote for the summer house, 18wx10d. It's south facing so we've asked for a slightly unusual pent in that it will slope toward the front of the building.
Cable run would be roughly 23 metres from the building to the electric meter but should be able to run along the boundary wall without needing to dig a trench up to the last 1.5 metres.

Want all the inverter/battery gubbins in the summer house if possible. Loses a bit of floor space but we're limited in where we could put it in the main house without a fair bit of work.

As far as I'm aware it should all come under permitted development so no concerns with planning permission there.

Not sure yet what the pent angle will be and my quick math works out that a 30-40 degree pent would add 5-8 foot to the height so doubt that it is practical.
I assume the solar panel fitters could knock up some kind of riser if need be?

Only concern is if there might be any glare from it being lower than a standard roof install. Not so much for ourselves, thinking of the neighbours.

Another consideration; currently have a 2 year old bp chargemaster chargepoint.
Any value in changing it to, say, a Zappi 2 for the solar integration or will it all work fine?

Also going to get a quote for an air source heat pump and/or thermal solar water but that's a much lower priority. The heating isn't that expensive to run, about £370 a year, and I suspect the payback time would make it uneconomical. The main issue is we'd need a cylinder and I'm struggling to see where we'd put it without a bit of remedial work.

 

[Hairyfool]

I have seen panels mounted on frames at the far end of a north facing garden against the boundary fence mounted on frames on the ground. The fact that there would be a summer house underneath in technical terms would be irrelevant.

The optimum angle depends on latitude but yes, around 30-35 degrees needs to be the target. Being a large flat area the potential wind loading would be quite significant and the angle is not high enough that snow loading cannot be ignored either. This would be a major concern for the structural strength of the summer house.

 

[Hotlush]

Looking like my biggest problem is because it's not a standard install, or particularly large, the installers are busy enough that they can pick and choose jobs.

 

[Hotlush]

So one company has failed to turn up twice so not impressed with them.
A local company did ring and had a good chat but again felt a bit fobbed off. No idea what kwhp panels they use but at 1.9m x 1.2m I'd struggle to get many on the summer house and they won't fit some on the house roof unless they can all slot together and I was looking at 2 either side of the dormer.

Oh well, will keep looking if any installers are a bit more open to a non-standard stick it on the roof and bugger off install.

 

[biffo]

So one company has failed to turn up twice so not impressed with them.
A local company did ring and had a good chat but again felt a bit fobbed off. No idea what kwhp panels they use but at 1.9m x 1.2m I'd struggle to get many on the summer house and they won't fit some on the house roof unless they can all slot together and I was looking at 2 either side of the dormer.

Oh well, will keep looking if any installers are a bit more open to a non-standard stick it on the roof and bugger off install.

There is a YouTube channel I follow which have shown a garden building like this.



Other option is to invest in Ripple and buy a share in a wind farm and the savings it brings

Join Ripple and save on your bills

Sign up to Ripple energy and power your home with cheaper, greener electricity and save on your bills.

rippleenergy.com

 

[Hotlush]

There is a YouTube channel I follow which have shown a garden building like this.



Other option is to invest in Ripple and buy a share in a wind farm and the savings it brings

Join Ripple and save on your bills

Sign up to Ripple energy and power your home with cheaper, greener electricity and save on your bills.

rippleenergy.com

Thanks for that.
They're a fair distance from me but if they don't cover my area it gives me some ideas I can pass on to the company I'm looking at for the garden building.

 

[Les burrows]

Hi biffo like the post above, also like seeing you have updated your Avatar good man.
Les.

 

[ARealHuman]

This has been on the MG Owner's Club website for some time:

Power your EV

You have taken your first step to help mitigate climate change and lower your emissions by opting to drive an electric vehicle. However, if you are charging from the grid, you are quite likely to...

www.mgevownersclub.co.uk

And I came across this on the BBC website a week or so ago:

Solivus Arc Solar energy solution

The Solivus Arc is creating a revolutionary solar energy solution for homeowners

usa.solivus.com

I have no idea how effective they are but thought the links might be helpful.

 

[Hotlush]

There is a YouTube channel I follow which have shown a garden building like this.

Had a chat with them. In the end they didn't go in to production, which is a shame but they were good enough to give me some info.
Over 11 months the 8 panel generated just under 2000kwh.

Tweaked the design to increase the roof space. Still 18'w x 10'd footing but a 20'w x 16'd roof; i.e a 6' canopy at the front.
That gives us a lot more space and should easily fit 12 panels.

Also finally started to get contact with companies willing to quote.
Most are in the region of £10-11k which is around what I was expecting.

Just need to chivvy the building builders to move to a formal quote so I have an idea how much to ask the bank for

 

[Tim Falkiner]

This is a very good Australian video on solar panels though you need to take into account UK conditions of higher latitude and maybe higher prices. I found it particularly interesting dealing with east/west roofs and percentage of solar use during the day versus percentage of grid use during the night.

I had assumed that since the house I live in had an east/west roof it was unsuitable but in fact an east/west roof can be better than a north (south in your case) facing roof.

 

[AK OK]

Had a chat with them. In the end they didn't go in to production, which is a shame but they were good enough to give me some info.
Over 11 months the 8 panel generated just under 2000kwh.

Tweaked the design to increase the roof space. Still 18'w x 10'd footing but a 20'w x 16'd roof; i.e a 6' canopy at the front.
That gives us a lot more space and should easily fit 12 panels.

Also finally started to get contact with companies willing to quote.
Most are in the region of £10-11k which is around what I was expecting.

Just need to chivvy the building builders to move to a formal quote so I have an idea how much to ask the bank for

Thence to the payback calculations?

Sounds like £20k+ investment to partially power your household, but how much power & for how long?

 

[Hairyfool]

And according to the Energy Saving trust the "typical" household could look to save around 20% of their electricity bill.

 

[Hotlush]

Thence to the payback calculations?

Sounds like £20k+ investment to partially power your household, but how much power & for how long?

4000 kWh per year; 16 years but that was based on a 28p tariff and I'm already looking at paying 40p+ when the current tariff ends.
It also doesn't take into account topping up at Octopus Go rates.

I've basically got 2 choices; do nothing and pay 2-3 x as much for electric from September (possibly more after the October cap change kicks in).
Or put that extra money on the mortgage, get a summer house and keep the electric bill around the same level it is now.
Either way I'm paying out more money, with the PV at least I get a summer house for it.

 

[AK OK]

4000 kWh per year; 16 years but that was based on a 28p tariff and I'm already looking at paying 40p+ when the current tariff ends.
It also doesn't take into account topping up at Octopus Go rates.

I've basically got 2 choices; do nothing and pay 2-3 x as much for electric from September (possibly more after the October cap change kicks in).
Or put that extra money on the mortgage, get a summer house and keep the electric bill around the same level it is now.
Either way I'm paying out more money, with the PV at least I get a summer house for it.

There's lots of assumptions in there though isn't there?
Big one being you can't just knock 4000 kWh off your yearly electricity bill - You have to use it as it is generated otherwise you get SFA by selling it to the grid & buying it back (at full price) when you do use it.
Or is there another £15k for a battery knocking about too? & even then....
Inverter lifespans? Panel efficiency degradation? Damages/replacements? Wear & tear?
Not sure myself...

 

[Hotlush]

There's lots of assumptions in there though isn't there?
Big one being you can't just knock 4000 kWh off your yearly electricity bill - You have to use it as it is generated otherwise you get SFA by selling it to the grid & buying it back (at full price) when you do use it.
Or is there another £15k for a battery knocking about too? & even then....
Inverter lifespans? Panel efficiency degradation? Damages/replacements? Wear & tear?
Not sure myself...

£15k for a battery?
I've been quoted significantly less than that for a 4.8kWp PV system with a 10kWh battery.

 

[AK OK]

£15k for a battery?
I've been quoted significantly less than that for a 4.8kWp PV system with a 10kWh battery.

Couple of Tesla powerwalls sure?

 

[Hotlush]

Couple of Tesla powerwalls sure?

On an average day I'll use about 8.5 kWh.
The Huawei battery they're proposing is expandable in 5 kWh increments up to 30 kWh but 10 should cover most days.
Top it up on Octopus Go means I should be able to shift most of my usage on to cheap rate and I'll keep charging the car during that window too.

 

[AK OK]

On an average day I'll use about 8.5 kWh.
The Huawei battery they're proposing is expandable in 5 kWh increments up to 30 kWh but 10 should cover most days.
Top it up on Octopus Go means I should be able to shift most of my usage on to cheap rate and I'll keep charging the car during that window too.

Hmm & presumably at some point the cheapo nighttime "spare" electricity will no longer be given away "for nought" as demand outstrips supply...

 

[bribagz]

So we've had some quotes and they've basically knocked the idea of having solar PV on the house roof on the head due to the dormer.

We had already been planning to get a summer house at the bottom of the garden so thinking of accelerating that and use it's roof space.
We're lucky enough have a fair bit of equity and putting it on the mortgage isn't excessive for us.
In theory the savings on electric would be around the same as our predicted increase when the tariff changes in September so we shouldn't be that much worse off and might even reduce our overall bills a bit.
Currently on Octopus Go 13.5p/5p tariff and looking like will be 40p/7.5p+ when we renew going on current offerings.

Have chatted to a local garden buildings company and they seem confident they can build one with sufficient strength to handle some panels on top.
So currently awaiting a quote for the summer house, 18wx10d. It's south facing so we've asked for a slightly unusual pent in that it will slope toward the front of the building.
Cable run would be roughly 23 metres from the building to the electric meter but should be able to run along the boundary wall without needing to dig a trench up to the last 1.5 metres.

Want all the inverter/battery gubbins in the summer house if possible. Loses a bit of floor space but we're limited in where we could put it in the main house without a fair bit of work.

As far as I'm aware it should all come under permitted development so no concerns with planning permission there.

Not sure yet what the pent angle will be and my quick math works out that a 30-40 degree pent would add 5-8 foot to the height so doubt that it is practical.
I assume the solar panel fitters could knock up some kind of riser if need be?

Only concern is if there might be any glare from it being lower than a standard roof install. Not so much for ourselves, thinking of the neighbours.

Another consideration; currently have a 2 year old bp chargemaster chargepoint.
Any value in changing it to, say, a Zappi 2 for the solar integration or will it all work fine?

Also going to get a quote for an air source heat pump and/or thermal solar water but that's a much lower priority. The heating isn't that expensive to run, about £370 a year, and I suspect the payback time would make it uneconomical. The main issue is we'd need a cylinder and I'm struggling to see where we'd put it without a bit of remedial work.

Friend of mine in a conservation area, put 4kWh solar PV on his summer house lying flat, and produces almost as much power as me. on a pitched S.E. Roof you should be fine,

 

[Gomev]

Hmm & presumably at some point the cheapo nighttime "spare" electricity will no longer be given away "for nought" as demand outstrips supply...

Such an optimist @AK OK
No reason to think overnight cheaper tariffs won't be around for many many years to come. Surplus of generation, with little industry or offices working overnight has to go somewhere. Power generation cannot be switched off and on with a flick of a switch.
Economy rates have been around since the 60s I think and will continue for a long time yet.