Solar Panels UK - is it worth it?

[phil4]

And then they (well, if not them, then "others like them") exclude battery storage

It's because they see battery output as brown energy. Yes, you may be well intention and only supply solar excess, time shifted using batteries, but the grid can't guarantee that, so no carbon credits, no claiming 100% green energy etc.

We already see Octopus overtly stopping this, by not allowing EV tariffs and enhanced SEG pricing. So it's entirely possible that there's a monetary reason to stop it too.

 

[WannabeOwner]

It's because they see battery output as brown energy. Yes, you may be well intention and only supply solar excess, time shifted using batteries, but the grid can't guarantee that, so no carbon credits, no claiming 100% green energy etc.

Understood, thanks.

But battery that only discharged / exported as an alternative to a Gas Peaker-Plant would be green (i think?)

Presumably no way to know whether punter was providing from PV or Battery, if they have one installed ... proper 1st world teething problem.

But my main thought is "Why pay generously for PV" when that is generated at times when it is sunny and, ergo, UK has plenty of generation choices - and Supplier should be able to shop around, and given they are required to buy all PV that consumer exports ... why pay a decent price?

Perhaps you've hit the nail on the head and that particular Supplier has spotted a Carbon Credits wheeze.

 

[phil4]

I suspect it's 100% about money, nothing to do with common sense. Look at the hurdles placed in your way to getting solar and exporting. You think that's just for safety? it's trying to protect income.

 

[Pink Duck]

Before those hurdles, choose wisely:

• Octopus Energy = Flux (East England) = 19.82 p/kWh, 32.17 p/kWh (16:00–19:00) (any solar, any batteries)
• OVO Energy = OVO SEG Tariff = 20 p/kWh (their solar, their batteries)
• E.ON = NextExportExclusive 16.5 p/kWh (their solar, any batteries)
• Octopus Energy = Outgoing Fixed = 15 p/kWh (any solar, any batteries, not available with IO/Go tariff)
• OVO Energy = OVO SEG Tariff = 15 p/kWh (their solar only)
• Scottish Power = SmartGen+ = 15 p/kWh variable (their solar, their batteries, biannual payment)
• Octopus Energy = Outgoing Agile = 10.79 p/kWh (average, 15–18 p/kWh during peak, not available with IO/Go tariff)
• British Gas = Export and Earn Flex = 6.4 p/kWh (variable, opening read + quarterly auto-read)
• EDF = Export Variable Tariff 5.63 p/kWh (any batteries)
• SSE = Smart Export tariff = 3.5 p/kWh (variable, any solar, storage may affect eligibility

For providers requiring MCS certificate/number, that’s 7–14 days on its own, by post! DNO export MPAN whenever they get around to it.

 

[phil4]

Before those hurdles, choose wisely:

• Octopus Energy = Outgoing Fixed = 15 p/kWh (any solar, any batteries)

Must not be on Go/Intelligent import.

 

[Pink Duck]

Similarly for Outgoing Agile, yes.

 

[phil4]

Similarly for Outgoing Agile, yes.

I didn't know that... was just looking at that and thinking that might be a good idea... but then it's a few pence difference for me, 11p here, 17p there... not worth the hassle.

 

[Pete UK]

Super exited (although not about the recent weather).

Scaffolding went up Weds. Install fully done in 1 day (3 guys) and operational by 5pm on Thursday and all up and running. One guy came back to finish the Bird mesh on Friday morning.

2 x Givenergy Hybrid 5.0 Inverters ~ Gen 3
4 x Givenergy 9.5 Gen 2 Batteries
27 x 420w Trina all black Panels (S,N,W !) on 4 roofs.

Although it’s been almost exclusively overcast and raining or drizzling the first 2 days I’ve been seeing about 2kW generated all day. The ramp up and ramp down was surprisingly very gradual; started at 1w at 0350am and builds up, the same at sunset all the way back down to 1w at 10pm ! I thought these things would get down to like 100w and then just give up !

I saw a peak of 5kW yesterday briefly and 7kW peak today, also very briefly. I have no idea how the north string is performing, or max, as I have 4 strings and it’s hard to tell which is which right now (with 400-600w from each of the 4 strings all with different orientations and number of panels !). Generating 2.4kW right now and it’s overcast. I guess it will become apparent on a fully sunny day. At least I know it seems reasonably balanced in these conditions. Bring on the sun !

Absolutely brilliant to be generating 1-2kW an hour when it’s overcast and raining. Unbelievable.

Generated 16.5kW already today till 3pm and 44kW in under 48 hours with overcast/ drizzly conditions. Batteries at 75%. Zero grid import/export. Now just need to get the scaffold removed so I can get the car on the drive to top it up.

 

[Mrklaw]

how are your two inverters handling batteries? are they 2 batteries per inverter? how do they divvy up any excess?

 

[Pink Duck]

Waiting on MCS certificate myself, having been through a similar process last week. Was told might be up to 14 days at this time of year. 52 kWh generated from last Sunday, car charged to 90% from that at 7.4 kW at times. Then export MPAN via Octopus Energy, then finally some additional payback.

 

[Mrklaw]

some big roofs here!

 

[Pete UK]

how are your two inverters handling batteries? are they 2 batteries per inverter? how do they divvy up any excess?

Yes, it’s 2 batteries per inverter. Right now it looks like this;

Solar at 2.2kW generation currently (7:20am).

String 1: 1,621w
String 2: 109w

String 3: 92w
String 4: 384w

(I guess 2&3 aren’t in the sun yet). This is the biggest difference I’ve seen between strings so far.

Inverter A: Charging at 583w
primary battery: 17%
secondary battery: 29%

Inverter B: Charging at 1.17kW
primary battery: 100%
secondary battery: 91%

They are divvying it up kind of randomly I’d say. One inverter seems to be more dominant. There is some cross charging happening (as expected). Waiting patiently for the EMS balancing solution to come out. There is a battery balancing trial going on at GivEnergy which I found out about on the GE forum. I have asked to go on it. There is one trial with the EMS product and a cloud based trial. I don’t have any more info right now as to which one I’ll get on, or indeed if I’ll even get on one as I’ve only just had my details passed on.
There are two options that can ‘reset’ the amount of charge going out of each inverter:
Option 1: Pause the battery charge/ discharge on the app using the ‘play/pause’ button /
Option 2: Reset one or both inverters in the cloud website using the ‘on/off button’.
There is a short period where you’ll export (between pause/play or inverter reset but both are very fast (fast fingers or fast inverter reset). This isn’t an ideal situation and only fixes the issue until the power flow changes and then they start to increase the cross charging again

I think the state of each set of batteries should eventually balance out the pair on each inverter after a while. I’ve not had a complete full-low cycle yet or grid charge. There is a difference between each battery pair which was there from the start of commissioning after the battery calibration and hasn’t quite evened out yet.

Today is looking like it should be a sunny day, so I’ll be watching it a bit more closely to see what happens.

 

[Pete UK]

…now they are both charging at

Inverter A: 1.2kW
Inverter B: 800w
(No cross charging)

inverter B’s batteries 100% and 94% with charging slowing down now.

When the panels are generating, the cross charging doesn’t seem to be as apparent or isn’t happening mostly. Seems to be more often when generation is low or when power flow changes.

 

[Mrklaw]

are you saying Givenergy are planning a firmware update for the inverters to speak more neatly to each other to allow parallel running without cross charging?

If so will keep an eye out for that - looking to get another 9.5 battery and might be worth the incremental cost to add a second AC3 inverter if they’ll work together well

 

[Pete UK]

are you saying Givenergy are planning a firmware update for the inverters to speak more neatly to each other to allow parallel running without cross charging?

If so will keep an eye out for that - looking to get another 9.5 battery and might be worth the incremental cost to add a second AC3 inverter if they’ll work together well

I don’t know about a firmware upgrade. But that would be logical, as I suppose all the data is available already because people are running Home assistant to fix this issue.

I think they are working on an EMS for the AC inverters currently (and also the hybrids, I believe) and also there is a trial for the physical EMS box and a cloud based trial/fix being worked in for the (hybrid/AC?) inverters. I think that’s the state of play. I’ve seen some reports of the cross charging problem NOT being evident on the Gen 1 inverters also.
So if you have an AC Gen 1 already. Just get another one. All should be good but don’t take my word for it; you’ll need to check.

It’s strange they haven’t fixed this already, seeing as people have tinkered about and fixed it themselves !

Meanwhile both batteries full already and exporting since midday ! Free electricity anyone? Shame it can’t go in the car yet.

Good day today for generation; 27kW and it’s not even 4pm yet.

 

[yessuz]

Can anyone TLDR explain how you use Home Assistant to charge Tesla via normal 7kw charger?

 

[JIBYC]

Can anyone TLDR explain how you use Home Assistant to charge Tesla via normal 7kw charger?

Assuming you have the Tesla plug in there are a number of ways of doing it.

In short you either want to automatically match the cars charging current to the available solar, or just limit it to what batteries can provide.

WHEN solar current updates

IF daytime = true & CarCharging = true

Change or reduce charging current

END

 

[94jdh]

I don’t know about a firmware upgrade. But that would be logical, as I suppose all the data is available already because people are running Home assistant to fix this issue.

I think they are working on an EMS for the AC inverters currently (and also the hybrids, I believe) and also there is a trial for the physical EMS box and a cloud based trial/fix being worked in for the (hybrid/AC?) inverters. I think that’s the state of play. I’ve seen some reports of the cross charging problem NOT being evident on the Gen 1 inverters also.
So if you have an AC Gen 1 already. Just get another one. All should be good but don’t take my word for it; you’ll need to check.

It’s strange they haven’t fixed this already, seeing as people have tinkered about and fixed it themselves !

Meanwhile both batteries full already and exporting since midday ! Free electricity anyone? Shame it can’t go in the car yet.

Good day today for generation; 27kW and it’s not even 4pm yet.

You shouldn't get any noticeable cross charging when generating on both, but you might if the dominant inverter isn't receiving much generation due to your position of the panels.
EMS is a fair way off yet, and the best bet for running it effectively is with GivTCP of which there is ready made software available to download on the Facebook page.
The Cloud based option is likely to be related to this at a guess considering Paul Landregan (Givenergy) previous comments on GivTCP.
Ideally, you should have a go at setting it up as cross charging is putting unnecessary cycling on the batteries back and forth.

 

[yessuz]

Assuming you have the Tesla plug in there are a number of ways of doing it.

In short you either want to automatically match the cars charging current to the available solar, or just limit it to what batteries can provide.

WHEN solar current updates

IF daytime = true & CarCharging = true

Change or reduce charging current

END

well, I have a podpoint charger - so tesla plug does not count.

 

[JIBYC]

well, I have a podpoint charger - so tesla plug does not count.

Doesn't matter really, it's all controlled via the car.

By plug in I meant the bit of software that controls the Tesla car from Home Assistant.