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Integrated Solar PV or not?


ashthekid

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I’ve seen the Viridian Velux Pv panels that are integrated into a slate roof for example and connect very neatly and pretty much flush with the roof tiling. Has anyone any experience with this particular integrated PV panels or any other integrated brands? Good idea or not?
I’m in the middle of a conversion project and not got to the roofing and tiling stage yet so could build them integrated which seems to make a lot of sense.

 

 

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56 minutes ago, Conor said:

I'm doing integrated panels using GSE mounting system. Adds about £1k to the job but I think it looks much better.

Our old mate @Jeremy Harris used the same system and when I first visited his place I did not notice them at all.

I am surprised it is adding so much to the cost.

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I still haven’t worked out the point of PV

On our first build the Sap predicted 

£200 annual saving 

Chatting to our Architect he’s saying perhaps we could get that upto £500 this time 

The  figures don’t stack up 

Perhaps another three years without taking any flights will do our bit for the environment ?

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You can look at it in a couple of ways. There's a lot of unnecessary (but desirable stuff) in most builds that doesn't have any saving. 

 

SAP is a poor way of assessing savings. With PV you probably need to alter how you use a house a bit to maximise self use. SAP has no way of knowing how you actually use your house and therefore the numbers are a bit of a finger in the air.

 

Finally it won't be worth it if the install is expensive. Buy the kit cheap, self install as much as you can and the it starts to look better financially. I suppose it also depends on where electricity prices are going.

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6 minutes ago, jamieled said:

I suppose it also depends on where electricity prices are going.

With the government's price cap, they seem be heading up with inflation.

Odd as wholesale prices have not moved much.

From Ofgem

 

 

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Edited by SteamyTea
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44 minutes ago, jamieled said:

You can look at it in a couple of ways. There's a lot of unnecessary (but desirable stuff) in most builds that doesn't have any saving. 

 

SAP is a poor way of assessing savings. With PV you probably need to alter how you use a house a bit to maximise self use. SAP has no way of knowing how you actually use your house and therefore the numbers are a bit of a finger in the air.

 

Finally it won't be worth it if the install is expensive. Buy the kit cheap, self install as much as you can and the it starts to look better financially. I suppose it also depends on where electricity prices are going.

Our daughter has purchased a Redrow home with PV 

They are the  inset type which don’t look as bad Plus they are on the back of the house So can’t really be seen 

She expected her electricity bills to be less But in reality they about the same 

 

We were required by planning to fit PV But with Heritage insisting on sash windows the type of slate we used There seemed little point spoiling the look of the house 

So we didn’t fit them 


The next two we build we may not have much choice With quotes of 7-9k quoted last time It would have to be a case of buy cheap and self install

Preferably on the back of the garage 

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My PV saves me about £250 per year in electricity.  I could get that up a bit (and gradually will) by thinning the trees that shade it early morning.  I can't do anything about the other tree that shades it in the late afternoon as that is in the neigbours garden.

 

My DIY install cost me about £1500 which means it will pay for itself in 6 years.  I believe it is only financially viable if you can buy the kit cheap and install it yourself.  If you had to pay for an install and the cost was say £4K then the payback time for me would be too long.

 

The developer houses with just a few panels, are probably not put there for planning reasons, but because the developers continue to build poor houses and it would fail the SAP calculations on it's own and they add some "renewable energy" to get just enough points from that to pass.

 

The will save you money if youcan use that electricity but you need something to use it in the daytime like your washing machine, dishwasher etc.  If you are out, set those to run on a timer in the middle of the day and at least some of the power they use will come from the PV.  If you are all out and nothing is on to use the power generated by the panels it will just get exported to the grid for no or little payment.

 

The other way to self use your PV power is a device to divert surplus generation to your immersion heater, but the developer house is likely to have a combi boiler and no hot water tank so that is not possible.

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7 minutes ago, jamieled said:

wonder how the Hinkley C cfd strike price will influence this

Probably going to be renegotiated as it is so delayed. 

Be interesting as the French Government will have to pick up the tab.

https://en.m.wikipedia.org/wiki/Flamanville_Nuclear_Power_Plant is still not producing.

Nor is https://en.m.wikipedia.org/wiki/EPR_(nuclear_reactor) producing on a regular basis. 1

2020 is the estimated date. 17 years after work commenced.

Edited by SteamyTea
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22 minutes ago, ashthekid said:

Could I not keep the electricity rather than giving it to the grid, save it in a Tesla style Powerwall battery and then use it all myself?

That would surely bring the bills down substantially more.

Properly cost the installed cost of the powerwall, the life of the batteries, battery replacement at end of life, and tell us the cost per kWh of your "free" stored energy that you can use.

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24 minutes ago, ashthekid said:

Could I not keep the electricity rather than giving it to the grid, save it in a Tesla style Powerwall battery and then use it all myself?

That would surely bring the bills down substantially more.

 

You can but the batteries are currently quite expensive.

 

We have a PV solar diverter - when it detects that power is about to leave the house it switches it to run two immersion heaters in our UVC so free* hot water. 

 

*free once the cost of the diverter is paid for but it was not that expensive and tells us it has saved 3000 KWh since installation in August 2016 so its paid for itself at least twice over so far.

 

We also both work from home so as well as laptop power etc - dishwasher & laundry all occur in daytime. Not hard on most modern machines to schedule the run time either.

 

We were lucky enough to get on the FIT before it was reduced so that gives us £1.50 benefit a day, that said we needed a MCS approved install to quality.

Edited by Bitpipe
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  • 3 months later...
38 minutes ago, TonyT said:

I’m sure they are less efficient when integrated, in 99.4%  certain I read that the cooling effect behind the panel improves efficiency, but this was 10 years ago when mine were fitted..

 

 

There is a loss of efficiency as temperatures rise, but there is also a rise in power as solar radiation rises.

Part of the reason for this is the standard test measure. Temperature and radiation levels are picked i.e 25⁰C and 1000 W/m². Then efficiencies changes are based around these. We should really use the Kelvin scale for temperature.

In practice, power output is a bit misleading, PV often produces relatively small amounts of power, relative to the input, but does it for a long time. 

Today in Penzance, I will get 16 hours and 21 minutes of 'normal' daylight, but even though it is sunny, very few PV modules are reacting in 2 axis to take full advantage of this. Most will be fixed in altitude and azimuth by the building design and orientation, so may not get as much direct beam sunlight on them as imagined, and because it is a clear day, there will be less diffused light.

This is why optimal yield days are often in the late spring and early autumn, but that is very weather and building orientation dependant. 

This is often used as 'proof' that a rise in temperature is very bad for PV production. Not always the case.

Like a lot of things, it is not as simple as it first seems.

 

Edited by SteamyTea
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3 hours ago, TonyT said:

I’m sure they are less efficient when integrated, in 99.4%  certain I read that the cooling effect behind the panel improves efficiency, but this was 10 years ago when mine were fitted..

 

 

That’s out of date info ;) Modern panel manufacturers are on top of that, plus the in-roof trays allow for quite a bit of convection airflow. They’re open top and bottom / side to side. Very little to argue over there imho and that from being on roofs fitting them 1st hand. 

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5 hours ago, TonyT said:

I’m sure they are less efficient when integrated, in 99.4%  certain I read that the cooling effect behind the panel improves efficiency, but this was 10 years ago when mine were fitted..

 

 

I was told this relatively recently . Built in ones less efficient at heat . Though how much less efficiency I’m not certain ( not a great deal from memory)

PV is ‘ better value ‘ with an EV and a battery . I estimate repayment for us at this point will be around 7 years .

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