3 phase planning

[AliG]

I have just emailed Octopus to see what the 3-phase SMETS2 meter availability is.

 

A couple of people say that Octopus have installed 3-phase meters for them in the south of England, so you might be OK @Dan F

 

As I have PV and an EV, and use a lot of electricity, I reckon that I could save £4-500 on Octopus Go or Agile.

 

At the moment the Octopus Go tariff is extremely cheap. They are charging 5p/kwh for 4 hours a day and the rest of the day their price is as cheap as the lowest electricity prices available to me on switching sites. The average price across the day of Octopus Agile might be even lower.

 

I reckon that I can get around 1/3-1/2 of my electricity use to be during the night.

 

 

[markc]

Octopus installed my 3 phase smart meter for free in Barnsley - i already had the cable into the cellar but no 2nd or 3rd meters.

[Dan F]

9 hours ago, AliG said:

A couple of people say that Octopus have installed 3-phase meters for them in the south of England, so you might be OK @Dan F

 

Our meter was installed about 6wks ago.  Octupus had been telling us that they had no idea at all regarding lead times and that'd we'd have to wait and see.  The way we got it done is the end was someone on a Tesla user group put me in contact with the meter instalation manager!

 

I haven't looked at the the whole Go vs. Agile vs. Tesla Tarif options yet, unclear which makes most sense.

 

 

[newhome]

10 hours ago, AliG said:

I have just emailed Octopus to see what the 3-phase SMETS2 meter availability is.

I contacted Octopus at the end of Aug to ask for an update on 3 phase meter availability (I have been on their list for nearly a year). I was told:

 

“I’m checking the list and I’m afraid it’s moving very slowly. It will be a long wait unfortunately. 

Thanks, 

Hector ?”

 

I would save ££ on Agile as I can easily push car charging and heating to overnight. In the interim I have today swapped to EDF on a flat rate with no smart meter (Go Electric tariff for EVs). It’s 12.59p as a flat rate and 11.49p for my second meter (used for heating). That’s still likely to save me quite a lot over the tariff I’m on with Scottish Power. 
 

So for the interim I’m sorted until a 3 phase smart meter becomes available on my area (Scottish Borders) through Octopus or otherwise. 
 

[AliG]

Thanks @newhome. Just had a look at it, the electric tariff is good, but the gas tariff is very expensive.

 

I am considering splitting my electric and gas providers to see if I can get a better deal that way.

 

When I get a quote at the moment, electricity is coming in at around 14.4p/kwh whereas EDF is 12.59, so more than 12% cheaper.

 

But EDF's gas price is 2.976/kwh versus the cheapest quotes at around 2.4p so more than 20% more expensive.

 

My current tariff which runs out in December is crazy cheap - 11.98p for electricity and 2.26p for gas. I totally lucked out when I switched to it.It does have a high 42p a day standing charge, so it only works out cheaper if you are a big user.

[newhome]

3 minutes ago, AliG said:

the electric tariff is good, but the gas tariff is very expensive.

I always forget that people get mains gas ?. No such luck here. I’d be on that in a heartbeat if I could. 

[andy]

On 19/05/2020 at 18:45, Dan F said:

Metering is "vector sum" across all three phase

 

Hi Dan

 

I had a 3 phase meter installed by Octopus last year - lots of challenges along the way and suffice to say I still have my old single phase supply as they mixed everything up...

 

However, they don't seem to know about "net metering" so perhaps the key phrase here is "vector sum" instead?  I am still not even on their outgoing tariff but hopefully will sort that soon.

 

The other down side of 3 phase is if I wanted Tesla Powerwall now, I need one per phase, so SSEN now stipulate, I really cannot see how the maths there adds up, alas   I have 6kW of PV, so I don't know how well 2kW/phase (minus active load) would charge the batteries - hell, on the bright side I'd never run out of battery capacity!

[Dan F]

2 hours ago, andy said:

The other down side of 3 phase is if I wanted Tesla Powerwall now, I need one per phase, so SSEN now stipulate

We weren't told we required this, but our permission may expire before we get hold of a powerwall, so this could be a concern if it's a change in policy. Can you share exactly what you were told and by who?

[Nickfromwales]

Why not batteries on the DC side? AC coupled is such a waste. DC also means you use a 3-phase inverter and lose nothing plus you size to what you want instead of the PW ‘one size fits all ( which it doesn’t ). Plus no limited throughput with SolarWatt batteries either. 
DC is a no brainer afaik. No DNO permissions needed either. I’d be surprised if the DNO let you put a PW on each phase!! plus your PV?!?

Edited March 1, 2021 by Nickfromwales

[andy]

1 hour ago, Dan F said:

We weren't told we required this, but our permission may expire before we get hold of a powerwall, so this could be a concern if it's a change in policy. Can you share exactly what you were told and by who?

 

@Dan F That's what I was told by my supplier when I tried to order 1 Powerwall late last year.  Apparently it's a new SSEN G99 regulations where they don't want the phases unbalanced but hey this might be the sort of thing where if you ask again you get a different answer... if you are told something different please do let me know and who you use as my preferred outcome is 1 x Powerwall.

 

@Nickfromwales I have started looking at the DC battery options as I have a 3 phase SolarEdge system but have not opened that conversation yet as I think this might be a different SolarEdge inverter, not sure I can retrofit but as I said I've not looked yet.  Downside of DC coupled is I'd need to put that in my comms room rather than in the garage that I can do for AC coupled Powerwall.

[Nickfromwales]

Power wall will want to charge off grid electricity in the winter, DC won’t. 
There are a few existing threads there for continuation of relative dialogue, so please try and resurrect one of those to keep things current   

[joth]

21 hours ago, andy said:

Downside of DC coupled is I'd need to put that in my comms room rather than in the garage that I can do for AC coupled Powerwall.

Just a note on this, it's likely too late anyway, but inverters generate heat, especially in the middle of summer when the house is already hot, and they work a lot better (and last longer) if kept cool. So putting it inside the thermal envelope, in what may(?) already be a fairly warm room, might not be ideal

[SteamyTea]

On 01/03/2021 at 12:28, andy said:

vector sum

A vector is a quantity and a direction.

[puntloos]

Dredging this topic up one-more-time.. but:

 

Any update on the world here? Octopus Energy rolling out 3phase better now?

 

I'd love to see some list of devices that benefit from 3phase (as a rule of thumb at least)

ASHP? MVHR? Lathe? Death Ray? PhotoPanels? Electric Car Charger? 

[newhome]

1 hour ago, puntloos said:

I'd love to see some list of devices that benefit from 3phase (as a rule of thumb at least)

24kw Electric boiler 

 

1 hour ago, puntloos said:

Any update on the world here? Octopus Energy rolling out 3phase better now?

I’m still ‘on the list’ and have heard nowt. Of course these days covid is the excuse for just about everything. 

[joth]

17 hours ago, puntloos said:

Dredging this topic up one-more-time.. but:

 

Any update on the world here? Octopus Energy rolling out 3phase better now?

 

I'd love to see some list of devices that benefit from 3phase (as a rule of thumb at least)

ASHP? MVHR? Lathe? Death Ray? PhotoPanels? Electric Car Charger? 

Elevator. (Always a good future proofing thought for a "forever home")

 

Car chargerS (plural). e.g. young kids may want their own car one day. If there's parking space for >1 car, think about how to charge them all.

 

 

 

 

[pdf27]

17 hours ago, puntloos said:

Dredging this topic up one-more-time.. but:

 

Any update on the world here? Octopus Energy rolling out 3phase better now?

 

I'd love to see some list of devices that benefit from 3phase (as a rule of thumb at least)

ASHP? MVHR? Lathe? Death Ray? PhotoPanels? Electric Car Charger? 

• Car charging already mentioned - most of Europe uses 3-phase so I think we're highly likely to see the more powerful chargers being 3-phase only. VW are working on an interesting one which is DC-coupled to the car so will be able to do vehicle-to-grid quite easily. I think that's very interesting for people on something like Agile.
• More PV: 8.5 kW in GSE trays to fit our proposed roof is £5700 ex VAT from Midsummer Wholesale. The 4kW equivalent is £3400 and the fixed costs of fitting it should be very similar - plus we save an additional 24m² of tiles - so while the value of electricity from a bigger PV system goes down as you consume less, the cost does too. That's an extra 4200 kWh/year for ~£1600 up front which is probably a bit better than the payback on a 4kW system. Not great as an investment, but if you're doing it I think it works better if you go big.
• Any machine tools. I'm an engineer and when I've mentioned I'd like to get 3-phase everybody immediately starts talking about how they'd love to have a lathe/mill/etc. in their shed but it needs 3-phase. Essentially anything with a cheap-ish electric motor in it benefits massively.

I'm not sure that I'd pay very much to get any of these, but in my case we're going to have to disconnect the supply to allow for demolition and there is 3-phase at the end of my driveway so the marginal cost of upgrading should be comfortably worth it. The key point is that it doesn't add any new limitations beyond possibly the metering technology - the distribution network is all 3-phase, and normally you're just connected up to one of them.

[andy]

On 14/03/2021 at 18:41, puntloos said:

Any update on the world here? Octopus Energy rolling out 3phase better now?

So I've had confirmation today that I am indeed on net metering and apparently that's the default that the Sprint 211 meters are set to.  Now this is indeed good news but my last challenge is to see if I can get just 1 Tesla Powerwall 2 installed (instead of 3...!)...

 

If I can then my plan is back on track as Tesla monitors usage across all 3 phases with CT clamps, where I am feeding back to the grid it draws more power on the phase it is connected to to top up for free.  Powerwall only feeds and protects its phase for the house but that's OK.

[andy]

On 14/03/2021 at 18:41, puntloos said:

I'd love to see some list of devices that benefit from 3phase

My reason for going 3 phase was two-fold:

 

1. Overall usage of the house may have exceeded 100A ultimately and sparky wasn't happy.

2. Future-proof for EV car charging and additional PV (already have 6.1kW so doubt I will add more now).

[puntloos]

On 15/03/2021 at 13:07, pdf27 said:

• More PV: 8.5 kW in GSE trays to fit our proposed roof is £5700 ex VAT from Midsummer Wholesale. The 4kW equivalent is £3400 and the fixed costs of fitting it should be very similar - plus we save an additional 24m² of tiles - so while the value of electricity from a bigger PV system goes down as you consume less, the cost does too. That's an extra 4200 kWh/year for ~£1600 up front which is probably a bit better than the payback on a 4kW system. Not great as an investment, but if you're doing it I think it works better if you go big.

Dumb question but what does 3vs1phase have to do with PV?

 

[TonyT]

You can get 3 times more PV on your roof/ ground mount installation than single phase.

 

[puntloos]

2 hours ago, TonyT said:

You can get 3 times more PV on your roof/ ground mount installation than single phase.

 

Because networks can't accept more than 4Kw "per phase"?

[pdf27]

6 hours ago, puntloos said:

Because networks can't accept more than 4Kw "per phase"?

Pretty much. Essentially the limit comes from the load on the three phases not being balanced, which gives all sorts of issues all the way back through the system. Any 3-phase load or generator will automatically be pretty well balanced.

There are other limits - for instance on how much you can put back into a system designed to deliver power - but the unbalanced load one is typically the one with the most impact on domestic supplies.

[Dan F]

8 hours ago, puntloos said:

Because networks can't accept more than 4Kw "per phase"?

11kW is pretty much garaunteed for 3-phase, where as single phase only 3.68kW can be assumed. But,  it depends on DNO and local network, you can get more on a single phase.

 

Our DNO (SSEN) were happy to allow 10KW + battery all a single phase.  That said in the end we decided to go 3-phase, and have a 12.5kW inverter.

 

[Steve J]

Sorry to post in an old thread.

 

I was wondering if any of the good folks here had any updates on 3 phase meter availability/behaviour from any of the UK suppliers.  I'm looking to get a 3 phase meter installed if I can, and having read a lot on various forums about the setup of 3 phase meters, i'm still unsure about what I might be getting into.  I'm interested to know the experience of anyone who has a 3 phase meter (smart or old school) installed in a domestic setting with PV only on 1 phase with regard to vector summation.  Has anyone got a meter where any power being exported on 1 phase nets off against any imports on the other phases so if my PV is exporting 2KW on one phase, but i'm importing 1KW on each of the other two phases, am I still charged for the imports, or does the meter look at the total summed across all three phases and record 2 -1 -1 =0 as my usage?