DIY Grid Tie (On-Grid) Solar setup
Discussion
Just running this by the experts here. New house, going to install 3.6 Kw+ of solar on an outbuilding near-flat roof. Done the measurements for panel spacing etc. looks like 2.7kw will fit on the roof, and then some more on the (south facing) side of the outbuilding.
I won't be selling any back to the grid. I can't. Its DIY.
My understanding is this (I work with solar btw - 12v, so the whole 240v part is new to me)
Panels - no problem - will hook them up in series (totally unobstructed) and parallel to achieve well in excess of the interter "start voltage"
Inverter - Growatt seem to be a good choice for price and features. I believe you get access to your electricity data online - is it cloud hosted? I assume I've got to make sure my Growatt model has wifi or ethernet or is there a seperate module?
Diverter - PVmate seems a good deal and spoken well of on here, that or Eddi. Will divert to water tank and / or hot tub (using submersible heater).
I run a small business from home so use power all day, so hoperfully a chunk of it will get used, and the hot tub will get used in the summer a lot too.
Anything to look out for?
I won't be selling any back to the grid. I can't. Its DIY.
My understanding is this (I work with solar btw - 12v, so the whole 240v part is new to me)
Panels - no problem - will hook them up in series (totally unobstructed) and parallel to achieve well in excess of the interter "start voltage"
Inverter - Growatt seem to be a good choice for price and features. I believe you get access to your electricity data online - is it cloud hosted? I assume I've got to make sure my Growatt model has wifi or ethernet or is there a seperate module?
Diverter - PVmate seems a good deal and spoken well of on here, that or Eddi. Will divert to water tank and / or hot tub (using submersible heater).
I run a small business from home so use power all day, so hoperfully a chunk of it will get used, and the hot tub will get used in the summer a lot too.
Anything to look out for?
Griffith4ever said:
Just running this by the experts here. New house, going to install 3.6 Kw+ of solar on an outbuilding near-flat roof. Done the measurements for panel spacing etc. looks like 2.7kw will fit on the roof, and then some more on the (south facing) side of the outbuilding.
I won't be selling any back to the grid. I can't. Its DIY.
My understanding is this (I work with solar btw - 12v, so the whole 240v part is new to me)
Panels - no problem - will hook them up in series (totally unobstructed) and parallel to achieve well in excess of the interter "start voltage"
Inverter - Growatt seem to be a good choice for price and features. I believe you get access to your electricity data online - is it cloud hosted? I assume I've got to make sure my Growatt model has wifi or ethernet or is there a seperate module?
Diverter - PVmate seems a good deal and spoken well of on here, that or Eddi. Will divert to water tank and / or hot tub (using submersible heater).
I run a small business from home so use power all day, so hoperfully a chunk of it will get used, and the hot tub will get used in the summer a lot too.
Anything to look out for?
Are you going to install PV (no battery) ? I won't be selling any back to the grid. I can't. Its DIY.
My understanding is this (I work with solar btw - 12v, so the whole 240v part is new to me)
Panels - no problem - will hook them up in series (totally unobstructed) and parallel to achieve well in excess of the interter "start voltage"
Inverter - Growatt seem to be a good choice for price and features. I believe you get access to your electricity data online - is it cloud hosted? I assume I've got to make sure my Growatt model has wifi or ethernet or is there a seperate module?
Diverter - PVmate seems a good deal and spoken well of on here, that or Eddi. Will divert to water tank and / or hot tub (using submersible heater).
I run a small business from home so use power all day, so hoperfully a chunk of it will get used, and the hot tub will get used in the summer a lot too.
Anything to look out for?
Growatt is at the junk end of the market IMHO
Do you / will you have an EV?
G98 or G99 application ?
As mentioned above you'll still need to do G98 notification (assuming your inverter is no more than 3.6 kW).
Although you can do most yourself, legally, you need an electrician to make the new circuit and connect to your consumer unit etc...
Connecting panels all on the same string in different orientations is not ideal as neither will operate optimally. You'll need to make sure you use different strings/MPPTs
Octopus do allow for 'DIY' installs to qualify for export payments, but there is an application fee and it is restricted to certain tariffs.
You can get an idea of your output by month by using PVGIS. Guides available on youtube.
Although you can do most yourself, legally, you need an electrician to make the new circuit and connect to your consumer unit etc...
Connecting panels all on the same string in different orientations is not ideal as neither will operate optimally. You'll need to make sure you use different strings/MPPTs
Octopus do allow for 'DIY' installs to qualify for export payments, but there is an application fee and it is restricted to certain tariffs.
You can get an idea of your output by month by using PVGIS. Guides available on youtube.
Cheers all.
Are you going to install PV (no battery) ? - indeed - no battery - the whole point is its ultra cheap (less than £1500 all in - don't care much ast this low investment about ultra efficiency)
Growatt is at the junk end of the market IMHO - well, if it works, but, I'm open to suggestions
Do you / will you have an EV? - Never
G98 or G99 application ? - G98 very likely
Conencting to CU - and I'm plenty experienced in domestic electrics, including installing RCDs in CUs - that's not a worry for me (and no, I'm not a rules and regs kind of guy - always done all my own electrics where necessary).
Panels in strings at different angles etc - I'm fine with that (I know that part well, was just fleshing out details) - they'll all be in the same orientation btw - just the ones on the side will be, well, side mounted.
As I said, just a simple system really
Are you going to install PV (no battery) ? - indeed - no battery - the whole point is its ultra cheap (less than £1500 all in - don't care much ast this low investment about ultra efficiency)
Growatt is at the junk end of the market IMHO - well, if it works, but, I'm open to suggestions
Do you / will you have an EV? - Never
G98 or G99 application ? - G98 very likely
Conencting to CU - and I'm plenty experienced in domestic electrics, including installing RCDs in CUs - that's not a worry for me (and no, I'm not a rules and regs kind of guy - always done all my own electrics where necessary).
Panels in strings at different angles etc - I'm fine with that (I know that part well, was just fleshing out details) - they'll all be in the same orientation btw - just the ones on the side will be, well, side mounted.
As I said, just a simple system really
Edited by Griffith4ever on Wednesday 27th August 11:48
Can you get a G98 without having an MCS approved install?
Do you need a G98/9? Possibly if you don't get caught exporting, you don't?
I suspect there's no grid-tie diverter type solution which will always keep exports to zero, unless you have some big heating element which will always take the excess power?
There are a few requirements which interlink I think.
You have to tick the boxes to get a G98
You have to obey/(not get caught breaking?) building regs.
You have to operate/control the system in a way that doesn't annoy your grid co or electricity retailer.
You may be subject to laws and rules about electrical safety. Some may apply where building regs don't.
I've been thinking more about the off-grid solutions. Like have some loads solar powered off-grid, probably with a battery, and switch them over to grid power whenever there's no solar. Say for instance you had some fridges and a few computers running from a solar/battery/inverter system. It could be only connected to the grid via a battery charger on winter days.
OTOH, someone yesterday pointed out quotes for quite cheap small MCS approved solutions. Get a small system with all the paperwork for export, then connect more panels.
Adding more panels might be to harvest more power in Winter, rather than to boost peak power in Summer.
In the 'fridges and computers' example, you might have a base load averaging 500W 24/7, 52 weeks of the year.
That's about a grand a year in normal rate electricity. If you can feed that from solar 300 days a year, there are real savings to be made.
And the possibility of having 'free' surplus power in the summer to run aircon.
But are we still in the situation where the best way to save money is to wait for MCS installers to cut their prices?
Do you need a G98/9? Possibly if you don't get caught exporting, you don't?
I suspect there's no grid-tie diverter type solution which will always keep exports to zero, unless you have some big heating element which will always take the excess power?
There are a few requirements which interlink I think.
You have to tick the boxes to get a G98
You have to obey/(not get caught breaking?) building regs.
You have to operate/control the system in a way that doesn't annoy your grid co or electricity retailer.
You may be subject to laws and rules about electrical safety. Some may apply where building regs don't.
I've been thinking more about the off-grid solutions. Like have some loads solar powered off-grid, probably with a battery, and switch them over to grid power whenever there's no solar. Say for instance you had some fridges and a few computers running from a solar/battery/inverter system. It could be only connected to the grid via a battery charger on winter days.
OTOH, someone yesterday pointed out quotes for quite cheap small MCS approved solutions. Get a small system with all the paperwork for export, then connect more panels.
Adding more panels might be to harvest more power in Winter, rather than to boost peak power in Summer.
In the 'fridges and computers' example, you might have a base load averaging 500W 24/7, 52 weeks of the year.
That's about a grand a year in normal rate electricity. If you can feed that from solar 300 days a year, there are real savings to be made.
And the possibility of having 'free' surplus power in the summer to run aircon.
But are we still in the situation where the best way to save money is to wait for MCS installers to cut their prices?
OutInTheShed said:
Can you get a G98 without having an MCS approved install?
Yes, as long as the inverter and isolators and wiring meet the requirements, then all you need is a sparky to sign it off (I know two - and they do NOT need to be MCS). Just gotta keep it under 3.68Kw (I've read its the inverter capacity that counts, and I've also read about DNOs approving higher wattage inverters so long as you keep your export capped under 3.68)Edited by Griffith4ever on Wednesday 27th August 13:48
Griffith4ever said:
OutInTheShed said:
Can you get a G98 without having an MCS approved install?
Yes, as long as the inverter and isolators and wiring meet the requirements, then all you need is a sparky to sign it off (I know two - and they do NOT need to be MCS). Just gotta keep it under 3.68Kw (I've read its the inverter capacity that counts, and I've also read about DNOs approving higher wattage inverters so long as you keep your export capped under 3.68)Edited by Griffith4ever on Wednesday 27th August 13:48
It doesn't in itself get you any payment for exports, but it means you can use readily available cheap grid tie inverters and (optionally) keep the system simple.
Personally, apart from aircon for a small number of days in the summer, I can't see great payback without a battery.
I'm not focused on water heating, more 24/7 base loads.
I think my first move might be to buy a single panel and slap it on the roof with some datalogging, because where I am supposed to be moving to might not be the sunniest parish in the kingdom during the Winter months. The sunshine data from places on the coast might be invalid inland, and there's some hills and trees in the mix.
Once I have some data for how many hours equivalent yield for each day over a winter, I'll be able to work out what's worth doing.
In the longer term, re-thinking heating, EV charging and a fair chunk of re-wiring might be required as well.
Also a long hard look at efficiency, it's often better just to not need so much power in the first place.
Griffith4ever said:
OutInTheShed said:
Can you get a G98 without having an MCS approved install?
Yes, as long as the inverter and isolators and wiring meet the requirements, then all you need is a sparky to sign it off (I know two - and they do NOT need to be MCS). Just gotta keep it under 3.68Kw (I've read its the inverter capacity that counts, and I've also read about DNOs approving higher wattage inverters so long as you keep your export capped under 3.68)With an approved inverter - check if it is in the ENA list https://www.ena-eng.org/gen-ttr/
it is a bit long-winded, but perfectly possible without MCS.
I have a self-installed system with an approved inverter.
I got the G99 sign-off from the DNO myself for zero cost. It is a bit of a process and unless you have an electrical background, an end-user would struggle with the forms.
I did get Part P approval for a 'new circuit' via an electrician - but, though it was a usefiul thing to do - I wasn't asked for the cert at any point in the process i.e. I didn't need it for the application. It was still nice to have my work checked.
I got export approval for 4.4kW - but that was the limit in the approval for the inverter and suited by array size. If I had wanted a bigger inverter, I am sure that would have been approved.
The part above about the 3.68kW 'cap' is true too. Oddly when my 4.4kW approval was going through, I was initially given the 3.68kW limit even though the inverter was 4.4kW and it was a G99 application.
On commisioning, I had to submit paperwork and then they told me I could remove the software limit.
I applied for an export MPAN via the DNO, which was issued within about a week.
On applying for an export tariff, the MPAN seemed to be the key to opening the door. The requirements to file certs for the new circuit and the MCS nonsense disappeared and I was put on export payments within two days.
I have written my own control software that minimises import , it analysise historic demand and then 'buys at best price'. It supports 12kWh of battery at present too.
The usual disclaimers. I am not an electrician, but am/was an electronic design engineer before moving more in to control systems and then networks.
An average end user isn't going to be able to manage a self installed system without a lot of learning.
Griffith4ever said:
Growatt is at the junk end of the market IMHO - well, if it works, but, I'm open to suggestions
I went for Victron. They really are designed to allow small systems and seem to encourage user control. Everything is made available.I think they came from the off-grid camper and boat type world.
Their kit seems to 'play nicely' too. You can parallel it up for more power, and duplicate systems for multiphase. All with a common DC system.
No ideas for a name said:
Yes, there is quite a bit of misinformation about.
With an approved inverter - check if it is in the ENA list https://www.ena-eng.org/gen-ttr/
it is a bit long-winded, but perfectly possible without MCS.
I have a self-installed system with an approved inverter.
I got the G99 sign-off from the DNO myself for zero cost. It is a bit of a process and unless you have an electrical background, an end-user would struggle with the forms.
I did get Part P approval for a 'new circuit' via an electrician - but, though it was a usefiul thing to do - I wasn't asked for the cert at any point in the process i.e. I didn't need it for the application. It was still nice to have my work checked.
I got export approval for 4.4kW - but that was the limit in the approval for the inverter and suited by array size. If I had wanted a bigger inverter, I am sure that would have been approved.
The part above about the 3.68kW 'cap' is true too. Oddly when my 4.4kW approval was going through, I was initially given the 3.68kW limit even though the inverter was 4.4kW and it was a G99 application.
On commisioning, I had to submit paperwork and then they told me I could remove the software limit.
I applied for an export MPAN via the DNO, which was issued within about a week.
On applying for an export tariff, the MPAN seemed to be the key to opening the door. The requirements to file certs for the new circuit and the MCS nonsense disappeared and I was put on export payments within two days.
I have written my own control software that minimises import , it analysise historic demand and then 'buys at best price'. It supports 12kWh of battery at present too.
The usual disclaimers. I am not an electrician, but am/was an electronic design engineer before moving more in to control systems and then networks.
An average end user isn't going to be able to manage a self installed system without a lot of learning.
Thanks.With an approved inverter - check if it is in the ENA list https://www.ena-eng.org/gen-ttr/
it is a bit long-winded, but perfectly possible without MCS.
I have a self-installed system with an approved inverter.
I got the G99 sign-off from the DNO myself for zero cost. It is a bit of a process and unless you have an electrical background, an end-user would struggle with the forms.
I did get Part P approval for a 'new circuit' via an electrician - but, though it was a usefiul thing to do - I wasn't asked for the cert at any point in the process i.e. I didn't need it for the application. It was still nice to have my work checked.
I got export approval for 4.4kW - but that was the limit in the approval for the inverter and suited by array size. If I had wanted a bigger inverter, I am sure that would have been approved.
The part above about the 3.68kW 'cap' is true too. Oddly when my 4.4kW approval was going through, I was initially given the 3.68kW limit even though the inverter was 4.4kW and it was a G99 application.
On commisioning, I had to submit paperwork and then they told me I could remove the software limit.
I applied for an export MPAN via the DNO, which was issued within about a week.
On applying for an export tariff, the MPAN seemed to be the key to opening the door. The requirements to file certs for the new circuit and the MCS nonsense disappeared and I was put on export payments within two days.
I have written my own control software that minimises import , it analysise historic demand and then 'buys at best price'. It supports 12kWh of battery at present too.
The usual disclaimers. I am not an electrician, but am/was an electronic design engineer before moving more in to control systems and then networks.
An average end user isn't going to be able to manage a self installed system without a lot of learning.
So you now have two MPAN's, one for import one for export?
Are you with Octopus? do other retailers offer you a SEG tariff?
In the long run minimising import sounds good, particularly peak price import.
It's not trivial to control, but keeping it simple rather than optimising to the nth degree, it doesn't seem that hard.
Some of the misinformation comes right from the top:
https://www.ukpowernetworks.co.uk/low-carbon-techn...
Which says you'll need an MCS cert to get SEG payments.
OutInTheShed said:
Which says you'll need an MCS cert to get SEG payments.
Octopus were the first (and only) provider to break ranksMCS is not an exact requirement - the wording is:
"You need to show that your installation and installer are certified through the microgeneration certification scheme (MCS) or a scheme accredited as equivalent"
OutInTheShed said:
So you now have two MPAN's, one for import one for export?
Are you with Octopus? do other retailers offer you a SEG tariff?
Yes, it is the same physical meter, it gets given two MPANs, one for import one for export which then get separately 'billed'.Are you with Octopus? do other retailers offer you a SEG tariff?
As far as I am aware you can actually have diferent suppliers signed up to each meter.
Yes, with Octopus. I could choose a fixed export or agile export (I thought I could only choose agile export in conjunction with agile import - but I may have got that bit wrong).
dmsims said:
Octopus were the first (and only) provider to break ranks
MCS is not an exact requirement - the wording is:
"You need to show that your installation and installer are certified through the microgeneration certification scheme (MCS) or a scheme accredited as equivalent"
It is an odd one.MCS is not an exact requirement - the wording is:
"You need to show that your installation and installer are certified through the microgeneration certification scheme (MCS) or a scheme accredited as equivalent"
Part of the reason I got my Part P and cert for the new circuit was I thought Octopus would need at least some certification.
They didn't.
They were given my G99 approval letter from the DNO.
Then nothing happened....
I rang up to make sure that they had it and were processing - to be told that they needed to apply for an MPAN and it could take months.
I stated I had one (since I got it direct from the DNO), and they took the number over the phone, asked for a photo of the meter to get an opening reading....
and I was on, supplying within two days (and that over a weekend).
If I short circuited the process by my phone call - I am keeping my head down.
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