Youll need to know how much they paid for their system. Might have overpaid hence the long ROI.
Also don't trust the installer calculation as they are wildly off if you look at the small print.
Solar panels and battery - any real world recommendations?
- Thread starter GinG
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Also don't trust the installer calculation as they are wildly off if you look at the small print.
Soldato
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Yeah my installer ROI was iirc 10 or 11 years, based on my data so far its going to be about 7
My installer seems to have (and i think they all do it) vastly underestimated generation (best not to over state I guess as an industry) plus the assumptions on not using a TOU tariff etc
Add in additional paid export (demand reduction) etc and it all mounts up
It isn't super easy to calculate the real ROI as you have to make some assumptions, eg would you stay on a normal tariff, risk fixing, risk agile or daily flexible etc.
I take my usage as [imported] * 0.95 + [generated] - [exported] = adjusted kWh usage and base my savings on that, I do this as most of my imported goes through AC-DC-AC conversion and I seem to get about 5% loss doing that (based on reported inverter generation and imported energy)
Important to be on good tariff and good export. Good can change so need to keep up with whats going on. Eg for export in 2.75 years I have been paid 4p, 8p and 15p at different times.
My installer seems to have (and i think they all do it) vastly underestimated generation (best not to over state I guess as an industry) plus the assumptions on not using a TOU tariff etc
Add in additional paid export (demand reduction) etc and it all mounts up
It isn't super easy to calculate the real ROI as you have to make some assumptions, eg would you stay on a normal tariff, risk fixing, risk agile or daily flexible etc.
I take my usage as [imported] * 0.95 + [generated] - [exported] = adjusted kWh usage and base my savings on that, I do this as most of my imported goes through AC-DC-AC conversion and I seem to get about 5% loss doing that (based on reported inverter generation and imported energy)
Important to be on good tariff and good export. Good can change so need to keep up with whats going on. Eg for export in 2.75 years I have been paid 4p, 8p and 15p at different times.
Apologies if already mentioned but seems Scottish Power are cutting their export rates from 12p down to 6p.
Thats really anoying.
Will have to try and see if we can export through Octopus (we use for import), although we have flexiorb, I know for a fact at one point they would accept that as father in law has the same an exports through them but I heard recently they might have stopped, Ill have to find out.
Very annoying though absolute mission trying to setup Scottish power. I had a feeling this would come though, it was only a matter of time before export rates started getting cut as more and more people start doing it.
EDIT. oh that was easy, 10 minute phone call to Octopus all sorted, they are going to change it over to them in about a week, they are paying 15p flat rate as well.
**** Scottish Power to be honest, god awful company.
Thats really anoying.
Will have to try and see if we can export through Octopus (we use for import), although we have flexiorb, I know for a fact at one point they would accept that as father in law has the same an exports through them but I heard recently they might have stopped, Ill have to find out.
Very annoying though absolute mission trying to setup Scottish power. I had a feeling this would come though, it was only a matter of time before export rates started getting cut as more and more people start doing it.
EDIT. oh that was easy, 10 minute phone call to Octopus all sorted, they are going to change it over to them in about a week, they are paying 15p flat rate as well.
**** Scottish Power to be honest, god awful company.
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It seems the fall on Scottish power is when you're on export only with them. All of the other SEG rates are unchanged when you're with them for import too. Im surprised the export only rate of 12p/kWh lasted this long actually. They dont like doing it. Even Octopus only offer about 4.1p/kWh for that if I remember correctly.
The MCS or nothing most use is very annoying though, I do agree.
The MCS or nothing most use is very annoying though, I do agree.
Octopus accepted the Flexiorb certification fine, as we already had an export MPAN he says was simple to switch it over.
I don't think that many if them do though.
My switch to octopus export is nearly complete. Currently on FIT and get 7.39p kWh export with it being 50% deemed.
Would definitely be better off with Octopus export at 15p. But if it dropped to half that, then not so much.
Is there a trend that export rates will be slashed like Scottish power soon?
I mean it should only be if import rates dropped a lot which they have not.
Would definitely be better off with Octopus export at 15p. But if it dropped to half that, then not so much.
Is there a trend that export rates will be slashed like Scottish power soon?
I mean it should only be if import rates dropped a lot which they have not.
I think the export rates that SP slashed were the standard SEG rates if you didn't have import with them, if you have import with them nothing changed, so no I don't think there is a trend.
It is unusual to get such a good export rate without import, OE only pays 4.1p unless you have import with them.
It is unusual to get such a good export rate without import, OE only pays 4.1p unless you have import with them.
You guys have any experience with micro inverters?
My parents have had a quote using 8 panels and each with their own micro inverter.
The whole quote seems expensive and I have a few issues on other things I need to research but wondering why anyone would go down this route vs just having a central inverter?
My parents have had a quote using 8 panels and each with their own micro inverter.
The whole quote seems expensive and I have a few issues on other things I need to research but wondering why anyone would go down this route vs just having a central inverter?
Is the quote from Heatable?
You only really need micro inverters or optimisers if you have shading issues, or are concerned about safety, or want panel level monitoring.
If you have nowhere to put a string inverter, then micro inverters can be a way around that.
If none of the above apply, use a string inverter.
You only really need micro inverters or optimisers if you have shading issues, or are concerned about safety, or want panel level monitoring.
If you have nowhere to put a string inverter, then micro inverters can be a way around that.
If none of the above apply, use a string inverter.
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No. It’s a Spanish firm.
There are potentially some shading issues due to a tall pine tree but I wouldn’t have thought enough to justify it given sun exposure in Spain.
My dad was talking about individual monitoring but I don’t really think he’d care about that beyond the first few days.
The quote is around €7k for 8 panels with micro inverters which sounds a lot for the benefit gained. They’re in an affluent area where I think everything gets upsold so just trying to understand whether they’re being sold something they need or just something with high margins for the installer.
My preference would probably be to double the number of panels and use a string inverter. They seem to have specced it based on current usage but my parents are saying it gives them the ability to ramp up usage of pool heater and AC without stressing about costs so feels it’d be quickly overloaded.
There are potentially some shading issues due to a tall pine tree but I wouldn’t have thought enough to justify it given sun exposure in Spain.
My dad was talking about individual monitoring but I don’t really think he’d care about that beyond the first few days.
The quote is around €7k for 8 panels with micro inverters which sounds a lot for the benefit gained. They’re in an affluent area where I think everything gets upsold so just trying to understand whether they’re being sold something they need or just something with high margins for the installer.
My preference would probably be to double the number of panels and use a string inverter. They seem to have specced it based on current usage but my parents are saying it gives them the ability to ramp up usage of pool heater and AC without stressing about costs so feels it’d be quickly overloaded.
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Please leave Scottish Power!
@Martynt74
Individual monitoring is a nice to have, I have it on my original SolarEdge system (I rarely look at), but not on the later systems I have fitted. Installers like it as they can see if there is a problem more easily, and where its located, but I find it hard to believe that installers check all their installed systems all the time, much more likely they will only look if the customer ever reports an issue.
Installers are obsessed with matching generation to past consumption, but as you say people usage patterns change. In the UK we now say fit as many panels as possible, panels are cheap, I've no idea how things stand in Spain. Obviously completely filling the roof may be too much in Spain, but the system needs to cater for future use, as that's likely to change.
Go back to them, ask them to quote for a string inverter, and more panels to allow for the air con and pool heater to be used more, would be worth getting other quotes as well.
Individual monitoring is a nice to have, I have it on my original SolarEdge system (I rarely look at), but not on the later systems I have fitted. Installers like it as they can see if there is a problem more easily, and where its located, but I find it hard to believe that installers check all their installed systems all the time, much more likely they will only look if the customer ever reports an issue.
Installers are obsessed with matching generation to past consumption, but as you say people usage patterns change. In the UK we now say fit as many panels as possible, panels are cheap, I've no idea how things stand in Spain. Obviously completely filling the roof may be too much in Spain, but the system needs to cater for future use, as that's likely to change.
Go back to them, ask them to quote for a string inverter, and more panels to allow for the air con and pool heater to be used more, would be worth getting other quotes as well.
Nice one. They’re a bit rubbish and are that classic case of someone with money just taking what’s been said.
I’ll try and get them to get some more quotes but I think I have a decent list of concerns/questions for them to think about.
If they take that on board it’s then up to them (usually they don’t!)
I’ll try and get them to get some more quotes but I think I have a decent list of concerns/questions for them to think about.
If they take that on board it’s then up to them (usually they don’t!)
Micro inverters have both advantages and disadvantages. The big three disadvantages are:
1. Cost.
2. Usually modern panels are say 470W, but micro inverters are 380W - which means around noon the panels are limited in how much power they can produce by the micro inverters (clipping).
3. If in future your parents add a home battery, there will be a lot of conversion happening wasting energy. Panels produce DC - micro inverter converts DC to AC - feeds AC to battery - battery inverter converts AC to DC - when battery is used to power appliances, battery inverter converts DC back to AC. Essentially one is ending with 3 AC/DC conversion steps, instead of 1 when hybrid inverter is used.
1. Cost.
2. Usually modern panels are say 470W, but micro inverters are 380W - which means around noon the panels are limited in how much power they can produce by the micro inverters (clipping).
3. If in future your parents add a home battery, there will be a lot of conversion happening wasting energy. Panels produce DC - micro inverter converts DC to AC - feeds AC to battery - battery inverter converts AC to DC - when battery is used to power appliances, battery inverter converts DC back to AC. Essentially one is ending with 3 AC/DC conversion steps, instead of 1 when hybrid inverter is used.
Haha done, I was never an import customer, but at the time they were paying the most for export and would also accept our solar certification.
They are absolutely shocking though, it tooke 9 months and a complaint to the energy ombudsman to get it setup, we did get a bit of a payout eventually.
Octopus...... 10 minutes on the phone lol.
took me 3 months before they would let me leave
Had my system installed Friday last week. 31 Aiko gen3 470w panels with two Tesla powerwall 3s and the gateway. The install went relatively smoothly apart from the fact they never cut the tiles to fit the brackets so they came back this week and redid the roof tiles cutting them to fit. Generated 91kw today and not used the grid since Friday apart from charging the wife's car at night. I've been watching it export nearly 10 KW to the grid every afternoon so waiting for my MCS cert now to setup my export with Octopus.
I've got my MCS Cert but still waiting on the DNO Approval which I hope isn't too far away now. Did have to nag a little to get my MCS Certificate as it was supposed to be "on it's way" but that never materialised. Also had to ask the installers to get in touch with the scaffolding company as that's been up 3 week now and the job was done on the 24th June. Hopefully it'll be gone by Thursday next week.