G99 application for a Solis hybrid inverter in UK

[marky0]

Hi,
I'm trying to get my head around which forms I need to complete for DNO approval in the UK, and quite frankly it seems to be a minefield !!
My set-up is very simple.
16 x 385W panels (east/west facing so ~5kW solar generation max if I'm lucky), Solis 6kW Hybrid Inverter (RHI-6K-48ES-5G), with 3 x 4.8kWh pylontech batteries.
I want to consume all the electrons I cultivate and never want to export power to the grid and will set-up the inverter accordingly.

But it seems that even if there is no export, DNO and G99 approval remains mandatory because I will parallel to the grid, but can't quite get my head around which form is appropriate.
The inverter is fully G99 compliant - ENA Type Test Compliance Number SOLIS/03855/V1
and G100 compliant to limit export to 0kW.

So can I fast track through form A1-2 : Application for connection of Fully Type Tested Integrated Micro Generation and Storage installations
But I struggle to answer the question :

The total aggregate capacity of the Power Generating Modules that are Electricity Storage devices do not exceed 16 A per phase and the total aggregate capacity of the Power Generating Modules that are not Electricity Storage devices do not exceed 16 A per phase.

for a 6kW inverter, or is it compliant to this question if export is set to 0kW ???

Or do I need to go through a protracted G99 application with form A1-1 : Application for connection of Power Generating Module(s) with Total Aggregate Capacity <50 kW 3-phase or 17 kW single phase
Which seems barmy for such a simple configuration with no export !

Any advice greatly appreciated for me and any others from the UK on the forum !

 

[Hartswood]

Hi, I need exactly the same help, I spoke to my DNO for guidance and he had no idea. I am going to install batteries with no solar and no export. I think anyone who manages to understand and complete the G99 forms should be awarded a doctorate, I'm going to attempt it today. I am ordering batteries from Alibaba and making a final decision on the inverter. My plan is to try to get approval for an 8kW Voltronic inverter and for island mode. I may not install an 8kW inverter, but if they approve 8kW I should be safe if I submit an amendment request for a smaller inverter. I can live without island mode, but it would be nice to have. If all fails I will install a Victron Multiplus 3000, which means I can complete a G98 after install. Later I think I can parallel it with another, which works out the same price as the Victron Multiplus 5000. I think I will fill in as best as I can, submit it and see what other info the DNO's project team want. I'm just going to give them basic information for the first attempt, inverter model number, any G98, G99, G100 certification it has. A schematic and a description of my setup. I am going to put not applicable for installer and tell them all AC connection will be made by an approved electrician.

 

[Ron-ski]

I guess I need to be awarded my doctorate, as I recently submitted and had approved a further circa 10kwh of export with UK Power Networks.

If they are your DNO I can certainly help.

PS For G99 you have specify the total possible export of all systems, if you want a limited export it may G100 but not sure on that as I got approved for what I required. I think even if you don't plan on exporting still get the full approval if you can, and then if exporting becomes profitable you can, leave it to later and the grid may not have capacity.

 

[SeaGal]

The simpler G98 procedure (i.e. install first then inform the DNO) only applies to devices that can export a max of 16A - i.e. 3680W at the nominal 230V.

As your inverter (RHI-6K-48ES-5G) has the _capability_ of exporting more than 16A you will need to go through a G99 approval, which requires acceptance from the DNO before installation. I'd recommend you do that before buying the inverter as the DNO could say they require £££ to upgrade the network before such a device is attached to it.

As far as I'm aware, the fact that you _could_ limit the export power to a value lower than 3680W on that inverter does not exempt from G99 approval as the DNO doesn't have control over what you set your inverter to actually do.

 

[Hartswood]

Well done doctor, just reading the G100 procedure. Looks like I've got to go G99, it limits storage to 16A per phase, storage and PV can go up to 32A, max 16A each storage and PV. So if battery only then limited to 16A, same as G98. No islanding, 16A export limit.

Do inverters need G99 certification to be fitted? I can't see anything about certification required for batteries.


Has anyone had islanding permitted on. G99? Power sector strikes and gas shortages could be a concern this winter

 

[Hartswood]

G99 A1.1 looks OK, but what additional sections do I have to fill in for a 5kW G99 approved inverter connected to a 15kW battery bank? If I want islanding is ther more to do?

Well done doctor, just reading the G100 procedure. Looks like I've got to go G99, it limits storage to 16A per phase, storage and PV can go up to 32A, max 16A each storage and PV. So if battery only then limited to 16A, same as G98. No islanding, 16A export limit.

Do inverters need G99 certification to be fitted? I can't see anything about certification required for batteries.


Has anyone had islanding permitted on. G99? Power sector strikes and gas shortages could be a concern this winter

 

[marky0]

@Ron-ski what form did you complete for you G99 application ? Was it A1-1 and how long did it take ?

 

[Ron-ski]

I'll did out the details when I get home.

Regarding batteries, if they are DC connected to the PV inverter, then it's just the PV inverter that you need to declare.

If the batteries are AC connected, and therefore have an inbuilt inverter then you need to declare both.

 

[Hartswood]

What does this bit mean on G99 A1-1"I confirm that the design of the Generator's installation has been carried out to limit output power imbalance to below 16A per phase"? Does this restrict the total A being pushed out by the inverter? Will a 10kW inverter be allowed to provide 10kW to the home load?

 

[Hartswood]

Looks like must be G99 certified Inverter. The forms for non G99 inverters are designed for manufacturers seeking type approval. Lucky,I came close to buying one of the cheap Chinese Victronic models knocking about.

 

[SeaGal]

Looks like must be G99 certified Inverter...

Yes, search for your _exact_ inverter at https://www.ena-eng.org/gen-ttr/

Make sure you find the GB version, not the NI one and then enter the "device reference" on your G98 / G99 form

 

[marky0]

After further reading of the G99 fast track process it seems very restricted to the definition of an Integrated Micro Generation and Storage installation. Page 26 of G99Amd8 states

Integrated Micro Generation and Storage : Power Generating Modules that are Electricity Storage devices and Power Generating Modules that are not Electricity Storage devices that form part of a Generator’s Installation. This is illustrated in Figure 4.7

What a definition ! Fortunately Figure 4.7 is a little more helpful


Even though this is provided as an "example" it is hardwired into G99 fast track form A1-2 with the criteria

The total aggregate capacity of the Power Generating Modules that are Electricity Storage devices do not exceed 16 A per phase and the total aggregate capacity of the Power Generating Modules that are not Electricity Storage devices do not exceed 16 A per phase.

which matches the definition in figure 4.7.

So even though my configuration

would look identical to the DNO it doesn't appear to meet the fast track definition for an Integrated Micro Generation and Storage installation

So unless anyone has any other ideas it appears that G99 form A1-1 is the only way to go for anything different from Figure 4.7.
Does anyone have an experience of how long the process takes for form A1-1 approval ?

 

[Ron-ski]

Back home now, so I used G99-form-a1.1 which I've attached a PDF version of it, pretty sure I downloaded the docx version from UK Power Networks website.

I sent in the application on 31 May, approval was received on 21 July, I already have 3.68kw system and applied for an additional 9.4kw, which was approved.


The "I confirm that the design of the Generator's installation has been carried out to limit output power imbalance to below 16A per phase" is for three phase systems, so if only a single phase system you can ignore that section completely - that had me stumped at first, but another forum answered that question.

For Power factor I just entered 1, which apparently most are.

Just noticed I never altered the DNO's details, it as per the attached PDF.

 

[Hartswood]

Back home now, so I used G99-form-a1.1 which I've attached a PDF version of it, pretty sure I downloaded the docx version from UK Power Networks website.

I sent in the application on 31 May, approval was received on 21 July, I already have 3.68kw system and applied for an additional 9.4kw, which was approved.


The "I confirm that the design of the Generator's installation has been carried out to limit output power imbalance to below 16A per phase" is for three phase systems, so if only a single phase system you can ignore that section completely - that had me stumped at first, but another forum answered that question.

For Power factor I just entered 1, which apparently most are.

Just noticed I never altered the DNO's details, it as per the attached PDF.

That's so handy, not as frightening as I originally thought. Checked through the list of G99 approved inverters. You can filter it for energy storage and capacity. Deye / Sunsynk appear to meet most of my requirements and have been recommended to me in another thread. I get the impression that all G99 compatible inverters are out of stock in the UK.

 

[SeaGal]

So even though my configuration
View attachment 107468
would look identical to the DNO it doesn't appear to meet the fast track definition for an Integrated Micro Generation and Storage installation

TBH, that makes sense from the DNO point of view. If your battery is fully charged and you have lots of light, you could export up to 5kWh (less your house load), which exceeds 16A. Whereas with the AC-coupled battery configuration, you are unlikely to want to export to the grid with your battery stored energy.

An alternative would be to go for the Solis RHI-3.6K-48ES-5G, which only requires G98 approval - i.e. install, commission and then tell the DNO. With 16 * 385W panels E-W facing, you'll only clip at the peak of the day in summer - and any excess (up to the 7kW max input to the Solis) will be directed to your PylonTechs.

 

[marky0]

TBH, that makes sense from the DNO point of view. If your battery is fully charged and you have lots of light, you could export up to 5kWh (less your house load), which exceeds 16A. Whereas with the AC-coupled battery configuration, you are unlikely to want to export to the grid with your battery stored energy.

Sorry, I don't agree. The entire point of the fast track G99 is that it has an export limitation scheme (as shown in the figures) so that the inverter is configured never to export more than 16A no matter what. It also needs G100 certification to prove that the export is not even exceeded under failure cases. My inverter would meet both these criteria, but still does not appear to eligible for fast track

 

[Hartswood]

Just stuck in my G99 A1-A following your guidance, only took me ten minutes to fill in. I had two inverters in mind either a Sunsynk 5kW and 8kW, couldn't make up my mind so just put both down on the form. They are both G99 certified. If they approve both then great, if not I'll just amend and resubmit. Didn't stick a plan in. If they want one I will. I made no comment about export limitations.

 

[Ron-ski]

You don't need a plan at this stage, you've applied for 13kW export, you can alter your kit after approval, you just need to send in a new application with the appropriate details, so long as it doesn't exceed what they approved previously it will be fine. My original application was for two additional inverters, that's now changed to one with a combined output almost equal to what they've approved.

 

[Hartswood]

Will I need a plan at any stage?

 

[Ron-ski]

Yes, this is what it says on my approval letter

On completion of your on-site installation

On completion of your on-site installation and commissioning please send me:​

a. the completed G99 Form A3​

b. an electrical schematic of the installation​

c. a site layout showing location of the generating plant and isolator​

d. the type verification test sheet for each relevant item of plant in accordance with G99 A2-3 / A2-4​