Solar ... In the news

ed110220

Martyn1981 wrote: »

Thank you. Now can I be cheeky and ask for your indulgence. In post #572, I suggested socket parity was close, and as an afterthought, mentioned new builds. How does this sound to you (it's more a mental exercise, so just ignore if you want):

For new build, stripping out scaffolding, a small element of roofing costs (being simpler), some economies perhaps from doing 1/2 a dozen properties etc, and less costs as no 'grant scheme/subsidy hoops', I think £4.5k for 4kWp seems reasonable, but will run with £5k, just in case. Then using the same set up as before

"4kWp install, southern UK, £5k, 4,000kWhs of generation pa. To avoid any arguments over financial losses, lets account for the costs via a 5% 25yr repayment mortgage. Adding £1k for a new inverter at yr 12, results in a repayment of £390pa."

£390/4,000 = 9.75p/kWh, which is equivalent to 40% consumption if leccy is 17p import and 5p export.

I appreciate that this is cherry picking, but just looking to see if we've reached (just) a viability point. Am I being reasonable, standing charges and twin tariffs can really much up some of these thought exercises?

Another thought, am I wrong to be aiming for viability in year 1. Would a fairer viability threshold, actually be when the PV breaks even over the whole 25 years, perhaps losing money in the early years, then making it back as inflation pushes leccy prices up. In which case, this example is easily viable, though no easier to 'sell' I suspect?

[Edit: Forgot to say. In reality, and cherry picking aside, I assume we are actually more like 2 years away from really being able to say that socket parity has been reached, and even then, still for only a minority of 'ideal' situations. M.]

Mart.

Hi Mart, good to see you're still so enthusiastic about solar (and with good reason I think). I still am, but need to replace our roof covering before we get any as it's reaching the end of its life.

Your thought experiment sounds about right. I don't see a problem with comparing the savings on electricity bill with interest on a mortgage used to pay for the equipment. I think that's how I'd go about it.

Ed

zeupater

Martyn1981 wrote: »

Thank you. Now can I be cheeky and ask for your indulgence. In post #572, I suggested socket parity was close, and as an afterthought, mentioned new builds. How does this sound to you (it's more a mental exercise, so just ignore if you want):

For new build, stripping out scaffolding, a small element of roofing costs (being simpler), some economies perhaps from doing 1/2 a dozen properties etc, and less costs as no 'grant scheme/subsidy hoops', I think £4.5k for 4kWp seems reasonable, but will run with £5k, just in case. Then using the same set up as before ....

Hi

Going even further, on a newbuild you'd more likely look to build the panels into the roof. The choice of our roof tiles was severely restricted by planning and therefore turned out to be pretty expensive. Overlapping plain tiles by 2/3 results in around 60 tiles/panel, or around 1000 under a 4kWp array, so replacing plain tiles would save around £400-£600, add in reduced timber & labour and you're probably looking at £800 to £1200. Of course, specialised 'in roof' mounting can work out pretty expensive, but it's not beyond the wit of a decent designer to create a much cheaper solution costing no more than the more usual 'on roof' mounting systems .... a nominal ~20% (range ~16% to ~24%) saving on your £5k startpoint makes a significant difference when calculating the parity point ....

HTH
Z

ed110220

zeupater wrote: »

Hi

Going even further, on a newbuild you'd more likely look to build the panels into the roof. The choice of our roof tiles was severely restricted by planning and therefore turned out to be pretty expensive. Overlapping plain tiles by 2/3 results in around 60 tiles/panel, or around 1000 under a 4kWp array, so replacing plain tiles would save around £400-£600, add in reduced timber & labour and you're probably looking at £800 to £1200. Of course, specialised 'in roof' mounting can work out pretty expensive, but it's not beyond the wit of a decent designer to create a much cheaper solution costing no more than the more usual 'on roof' mounting systems .... a nominal ~20% (range ~16% to ~24%) saving on your £5k startpoint makes a significant difference when calculating the parity point ....

HTH
Z

I'm not sure of that as all the new-builds I've seen with solar have the same type of roof mounted systems that are retrofitted. Probably because the industry mainly caters for retrofit.

I think I'd prefer the panels to be on the roof, rather than part of it, as it would make replacement in case of fault or accident easier and also a roof should last longer than solar panels (ours is only reaching the end of its life after 65+ years).

What is disappointing though is newbuilds with solar seldom seem to have been designed with it in mind. Instead of simple pitched roofs with nice simple arrays you get fussy hips and dormers etc with panels scattered about.

zeupater

ed110220 wrote: »

I'm not sure of that as all the new-builds I've seen with solar have the same type of roof mounted systems that are retrofitted. Probably because the industry mainly caters for retrofit.

I think I'd prefer the panels to be on the roof, rather than part of it, as it would make replacement in case of fault or accident easier and also a roof should last longer than solar panels (ours is only reaching the end of its life after 65+ years).

What is disappointing though is newbuilds with solar seldom seem to have been designed with it in mind. Instead of simple pitched roofs with nice simple arrays you get fussy hips and dormers etc with panels scattered about.

Hi

There's a self-build property around here which has gone down the integrated route & I must say that the results are excellent ... nice shiny black panels with dark-grey roof-tiles at the same level, it really looks seamless. I watched the build as it progressed and it seems that the roof below the panels is covered with plywood (could be a synthetic board(?)) then layered rolls of different materials ... I don't know what they were as I only saw from a distance whilst passing, but I'd guess that they were some form of airgap material layer and then a breathable fabric ... then aluminium mountings were fixed directly to the surface (ie no brackets) and the edges of the pv area were lead flashed .....

Personally, although they look really good, if considering FiT payments I'd be a little concerned about restricted airflow beneath the panels affecting the performance, but in a non-subsidised parity scenario I'd rather save the 20% to 25% up-front cost and have a great looking building than 10% extra generation on sunny days when I probably wouldn't need it all.

My guess is that many projects are started without fully considering pv, let alone the integration of the pv, therefore they're added as an afterthought .... hopefully, this will eventually be addressed as architects and builders become more experienced with renewables.

HTH
Z

Martyn1981

ed110220 wrote: »

Hi Mart,
Your thought experiment sounds about right. I don't see a problem with comparing the savings on electricity bill with interest on a mortgage used to pay for the equipment. I think that's how I'd go about it.

Ed

Cheers Ed, I felt as a new-build, the PV cost would probably end up on a mortgage. But if the additional mtg payments were equal to (or less) than the income/savings from the PV, then you have viability.

It'll be interesting to see what happens with general panel pricings. I'd expect the growing demand to prevent any price reductions for a while, and the EU:China agreement is a sticky issue, but does allow for price reductions if EU gets out of step with rest of world. But as and when they come down again, you could see something remarkable.

Try this out for an eye-opener:-
£5k purchase, from 1% current/cash savings account, depreciated over 25 years, means an annual cost of £250. £250/4,000 = 6.25p, equal to about 10-15% consumption (15p import 5p export).

All depends if prices come down, before general inflation pushes all the other costs up, and this is a very, very 'ideal' situation.

@ Zeup. Pics of in-roof PV do look nice. I think the French installs have to be in-roof to qualify for subsidies. There are also PV slates, here's a random link:

http://www.solarslate-ltd.com/product-information/the-innovative-slate.aspx

Could waffle forever (apologies) but did say way back somewhere, that it would be nice to see new estates being built with solar in mind, say 3 storey town houses to the north, houses in the middle, and bungalows to the south.

Also, not far from me, there are a whole load of town houses and flats (3 storeys) all going up with PV (yes, flats with PV ). Sadly, the PV is in bunches of 9 (3x3) with plenty of room to the sides, top and bottom. But maybe there is a max kWp for the estate, as so many PV installs in one place. I'm just about nosey enough to ask why they didn't go 4x4 ...... we shall see!

Mart.

tunnel

Martyn1981 wrote: »

Also, not far from me, there are a whole load of town houses and flats (3 storeys) all going up with PV (yes, flats with PV ). Sadly, the PV is in bunches of 9 (3x3) with plenty of room to the sides, top and bottom. But maybe there is a max kWp for the estate, as so many PV installs in one place. I'm just about nosey enough to ask why they didn't go 4x4 ...... we shall see!

Mart.

Never thought of that with the estate i pass every day i mentioned...everyone with some sort of panels but none with anything over 10 panels.

ed110220

tunnel wrote: »

Never thought of that with the estate i pass every day i mentioned...everyone with some sort of panels but none with anything over 10 panels.

This has been built round the corner from me - no evidence of any limitations in panels per house.

I'm hoping prices will come down enough so we can have a new roof covering and solar PV installation, probably in two years time.

Ed

tunnel

ed110220 wrote: »

This has been built round the corner from me - no evidence of any limitations in panels per house.

I'm hoping prices will come down enough so we can have a new roof covering and solar PV installation, probably in two years time.

Ed

Wow, so many panels. The estate i pass is on its own without any surrounding houses to soak up any excess generation, does beggar the question though doesn't it, that if it is like Mart says, then why didn't someone think to build the infrastructure in before starting the estate(will be over 2000 houses)

Martyn1981

tunnel wrote: »

Wow, so many panels. The estate i pass is on its own without any surrounding houses to soak up any excess generation, does beggar the question though doesn't it, that if it is like Mart says, then why didn't someone think to build the infrastructure in before starting the estate(will be over 2000 houses)

I'll second your wow, and add a strewth!

Sadly, I suspect that the 3x3's are more likely to be a financial decision. "What can we get away with to look green, but cost the minimum?" I hope I'm wrong, as the extra cost of going to 12 panels, would have been minimal at the time, maybe £500 per property. Now it would probably be 3 times that?

I do believe in 'better than nothing', but a shame not to have maxed out the roofing potential. But I don't know the full story and my [STRIKE]nosey[/STRIKE] inquisitive mind is starting to ponder. Hmmm.

Mart.

spgsc531

Pretty sure I've seen before, that there is new legislation coming in that will mean all new homes will have to have PV by 2019(?)

Public buildings before then I think(?)

Can't remember the link.

From what I recall there is two new pieces of legislation, overlapping.

Perhaps someone has more concrete info?