Fitting Battery to Solar

QrizB

tamste said:

Just looking at the prices .. I thought batteries were 0 rated for VAT but everybody seems to be pricing them with 20% VAT?

Zero rated when installed by a VAT-registered company, 20% when sold to Joe and Jo Public.

Quote from a supplier's website:

For the zero rate to apply, the supply of the solar panels and their installation must be the responsibility of the same business in the same supply (i.e., a supply and install contract).

Martyn1981

tamste said:

Just looking at the prices .. I thought batteries were 0 rated for VAT but everybody seems to be pricing them with 20% VAT?

Zero rated if installed at a domestic property with PV, or that already has PV. Until early last year, you only got zero rated if installed with (at the same time) PV, so some folk were adding one panel, just to qualify.

Batts alone can help with leccy costs, distribution, and greening grids at peak times, so perhaps batts (without PV) should get zero rating, but I don't think that has happened yet(?)

EricMears

It'll be the old swindle !   VAT free IF a particular firm supplies & fits.  Buying your own or from an 'unregistered' fitter will attract cat

tamste

With respect to the DNO, they have agreed a 10kWh export for the solar system. As the inverter is a hybrid type, would they still need an application as the inverter itself limits the export to 10kWh from what I understand (though might have got this wrong)?

If I go with the Growatt APX option (say 20kWh of battery), any idea what a MCS registered electrician might charge for installation?

Qyburn

tamste said:

With respect to the DNO, they have agreed a 10kWh export for the solar system. As the inverter is a hybrid type, would they still need an application as the inverter itself limits the export to 10kWh from what I understand (though might have got this wrong)?

DNO limit will be either power (normally expressed in kW) or current (Amps).  They won't care about the capacity of the battery, only the rate at which it can discharge.

I have a feeling the odd threshold for G.98 is actually 16A but they quote power assuming 230V to get 3.68kW.

QrizB

Qyburn said:
I have a feeling the odd threshold for G.98 is actually 16A but they quote power assuming 230V to get 3.68kW.

That's my understanding too. IIRC there was some discussion back when G59 (predecessor to G98) was first floated re. what the 16A limit really meant in terms of power, and it was codified as 16A at a nominal 230V.

tamste

So with 10kWh agreed on export with a 3 phase supply fed through the same hybrid 10 kWh inverter, they are likely not to require an application?

G98 specifies maximum demand (without load limiting device) as 18 Amps per phase, not 16A.

Also, the inverter model and capacity is included on the G98, so I presume I would need to make a new application if I changed the inverter?

QrizB

tamste said:

G98 specifies maximum demand (without load limiting device) as 18 Amps per phase, not 16A.

Where's that recorded?

Para 2.3 of the G98 specification says  "16A per phase":

https://www.energynetworks.org/assets/images/Resource library/ENA_EREC_G98_Issue_1_Amendment_5_(2021).pdf

Para 2.6 indicates this to be equivalent to 3.68kW for a single-phase installation, or 11.04kW for thtee-phase.

Notwithstanding that,

tamste said:

So with 10kWh agreed on export with a 3 phase supply fed through the same hybrid 10 kWh inverter, they are likely not to require an application? 

If your DNO notification was for a 10kW three-phase hybrid inverter, I would imagine that you won't need to make another notification if you add batteries to it.

But you should check with your installer (and if they're the ones fitting your batteries, they'll take care of it all in the background for you).

tamste

DNO application, which was approved, states:

Premise Details

Domestic/Non-Domestic?  Domestic

Type of Premise: Residential house/bungalow

Smart Meter installed on site? No  (note there is a 3ph smart meter, but it wasn't on the application?)

Number of Phases: Three Phase

DNO cut-out rating known? Yes

Premises Cut-out Rating: 100Amps per Phase

Final or Proposer Earthing Arrangements? TN-C-S (PME)

Identified as a looped service? No

Demand Details

Maximum Demand (without load limiting device): 18.00 Amps per Phase

Import or load limiting device on premises? No

Agreed export capacity (including G100 devices): 10.00 kW

G100 export limiting scheme on premises? No

and then lists under table 1 - Device(s) to be installed which is Solar PV with the MOD inverter

Qyburn

That looks like G.99, in particular the reference to export limit. In which case there should be an Offer in response, which should be accepted before going ahead. Then when the system's commissioned the details of equipment, test results etc are sent to the DNO, and finally (you hope) DNO responds confirming it's all in order and complies with their offer.

Under G.98 you don't apply, just tell them afterwards.