PV Installation question

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LUmney

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I'm not an electrician.
I'm looking at getting PV installed at my house but I'm being told a few different things by different people that contradict each other.
First off is the installation of the panels, I know there has to be 300mm from the edge of the roof, etc but is that still the case if your house is a mid-terrace? Since there isn't an updraft, etc, at the join of the properties either side do I still have to leave the 300mm each side?
Second is the G99 approval, I'm potentially looking at 16-18 panels, total rating around 7.2kWh BUT it's split across 2 sides of the roof so it would never produce the full capacity (house is East/West facing). I was looking at a 5kWh inverter but I've been told that most applications in my area are usually either denied OR approved with a limiting devices being required, has anyone heard of something like this (DNO is Western Power).
 

Richard-the-ninth

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Will it be worth it?
As you said, at most only 50% will get sunshine, so how long will pay back be?
(I genuinely have no idea, which is why I am asking, as you have the figures, so you know how much 16-18 panels + installation will cost)
 
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I would start by questioning why you want PV and why you want so much?

You do know there is no feed in tariff any more? So imho any PV install now has to be on the basis that you will be self using as much as you can to reduce your electricity import costs and trying to export as little as possible.

If you take that view it can be viable, as long as you keep the costs down which probably means a good deal of shopping around. For that approach you do NOT need am MCS registered installer. And probably something like 5kW of panels split over your 2 roofs into an dual mppt inverter with an output limit of 3.68 kW under G98 with no prior approval needed.

To go just over that to G99 will likely be a lot of expense and grief for very little extra gain.

And if you are thinking of the "smart export" payment of about 5.5p per unit, do the sums, work out how much you will get paid and how long it will take to repay your costs. TIP it will not be worth it, and it is imho not even worth the extra cost of an MCS installer. (you need am MCS install to claim the smart export payment)

Concentrate on cheap, simple and maximum self use and it is probably viable.
 

LUmney

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Thanks for the reply, I don't care about the FIT, I'm more interested in lowering my electricity bill which, based on current usage over the last 12 months will likely top £3300 per year.
Looking at the Photovoltaic Geographical Information System and using their figures the dual roof array and battery/ies will pay for itself in 7-8 years PROVIDING I have access to cheaper rate overnight electricity, either economy 7 or better still Octopus Go.
Again, same with the SEG, I'm not overly fussed about that, but I'd rather everything be above board with the ability to upload some to the grid in the summer months IF I don't use it in the house.
 

LUmney

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Will it be worth it?
As you said, at most only 50% will get sunshine, so how long will pay back be?
(I genuinely have no idea, which is why I am asking, as you have the figures, so you know how much 16-18 panels + installation will cost)
The panels with a 8.4kWh battery will be about £9.5k all in, if I can charge the battery overnight on cheaper rate electricity then according to the figures produced by the Photovoltaic Geographical Information System (minus 15% of their estimates) the system should pay for itself in 7-8 years.
I've estimated an 8.4kWh battery will cut full rate usage by around 50% but even if it only cuts it by 40% it's still viable due to the overall reduction in my electricity bill.
 

Stuboy1

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Other questions are how high is your roof and what is it made from, will you need a scaffolding erected? If so find out how much that will be and get it done yourself perhaps? Deffo oversize panels go for G98 or G100 ( but from what i have heard Western Power dont understand G100 and add everything together rather than taking the limit device. Maybe someone with more knoledge can confirm or deny this?) Solis do nice inverters with limiting have a look at them ;-)
 

LUmney

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Other questions are how high is your roof and what is it made from, will you need a scaffolding erected? If so find out how much that will be and get it done yourself perhaps? Deffo oversize panels go for G98 or G100 ( but from what i have heard Western Power dont understand G100 and add everything together rather than taking the limit device. Maybe someone with more knoledge can confirm or deny this?) Solis do nice inverters with limiting have a look at them ;-)
One of my neighbours has a son that does scaffolding, I'm planning on asking him for a price since I've done him plenty of favours as he's grown up, mainly keeping things hidden from his dad.
The roof is tiled.
I'd like to use a 5kWh hybrid inverter, simply because it'll allow me to have the separate roof sides on different strings.
I'll take a look at the Solis range, thanks for the information, I had primarily been looking at SolarEdge ones.
 
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Other questions are how high is your roof and what is it made from, will you need a scaffolding erected? If so find out how much that will be and get it done yourself perhaps? Deffo oversize panels go for G98 or G100 ( but from what i have heard Western Power dont understand G100 and add everything together rather than taking the limit device. Maybe someone with more knoledge can confirm or deny this?) Solis do nice inverters with limiting have a look at them ;-)
I've never had any problems with WPD, apart from one predantic fella whose name I won't mention. What they like is notifying in advance before you fit the system for G100 installations. You will almost certainly need the limiting device, although you can ask to backfeed more than 16A - I used ask them how much they will allow for a particular site, but that was when we had the FiT and sending as much as possible back to the grid paid dividends. As Solis have limiting devices built in (you need an amp clamp on the meter tails) and there is no FiT, I no longer worry about that, send WPD the G100 cert and picture of settings from the inverter after fitting if requested.
 
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First off is the installation of the panels, I know there has to be 300mm from the edge of the roof, etc but is that still the case if your house is a mid-terrace? Since there isn't an updraft, etc, at the join of the properties either side do I still have to leave the 300mm each side?
you don't need the 300mm on shared edges, but it's useful to leave a bit of a gap to the neighbours so you aren't interfering with their roof in any size shape or form - saves arguments aabout any potential damage / leaks.
 

LUmney

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you don't need the 300mm on shared edges, but it's useful to leave a bit of a gap to the neighbours so you aren't interfering with their roof in any size shape or form - saves arguments aabout any potential damage / leaks.
Thank you for both posts sir, the information is greatly appreciated.
 

Stuboy1

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A hybrid inverter generally means its got a DC output to feed a battery (be careful that isn't the battery of your choice, its a battery of their choice!) You just need a "multi string" inverter with separate MPPT for each channel. My own inverter is the Solis 5k which can take 5.8KW of panels.
Hope it all goes well.
Cheers
Stu
 
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OP do you have a hot water tank? If so adding a device like the SOLIC 200 means you divert excess production to your immersion heater before you export too.

This is our set up and we rarely use the boiler for hot water in the summer months
 

revor

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An issue is if you charge your battery from the grid at night then following day if you are generating a lot from solar you could then be exporting if you do not use it up. You wont be able to get a cheap rate at night and get a good SEG. You can have octopus go but if you want that you will only get 4 p I think for export. Variable export priced on wholesale price in 1/2 hr slots .
 
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